Sunday 20 November 2011
Saturday 20 August 2011
digital camera info.....
"Digicam" redirects here. For the military camouflauge method using micropatterns, see Military camouflage#Digital camouflauge.
A digital camera (or digicam) is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography. Most 21st century cameras are digital.[1]
The optical system works the same as in film cameras, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, just as with film but the image pickup device is electronic rather than chemical. Most digicams, apart from camera phones and a few specialized types, have a standard tripod screw.
Digital cameras are incorporated into many devices ranging from PDAs and mobile phones (called camera phones) to vehicles. The Hubble Space Telescope and other astronomical devices are essentially specialized digital cameras
Types of digital cameras
Digital cameras are made in a wide range of sizes, prices and capabilities. The majority are camera phones, operated as a mobile application through the cellphone menu. Professional photographers and many amateurs use larger, more expensive digital single-lens reflex cameras (DSLR) for their greater versatility. Between these extremes lie digital compact cameras and bridge digital cameras that "bridge" the gap between amateur and professional cameras. Specialized cameras including multispectral imaging equipment and astrographs continue to serve the scientific, military, medical and other special purposes for which digital photography was invented.Compact digital cameras
Most, apart from ruggedized or water-resistant models, incorporate a retractable lens assembly allowing a thin camera to have a moderately long focal length and thus fully exploit an image sensor larger than that on a camera phone, and a mechanized lens cap to cover the lens when retracted. The retracted and capped lens is protected from keys, coins and other hard objects, thus making it a thin, pocketable package. Subcompacts commonly have one lug and a short wrist strap which aids extraction from a pocket, while thicker compacts may have two lugs for attaching a neck strap.
Compact cameras are usually designed to be easy to use, sacrificing advanced features and picture quality for compactness and simplicity; images can usually only be stored using lossy compression (JPEG). Most have a built-in flash usually of low power, sufficient for nearby subjects. Live preview is almost always used to frame the photo. Most have limited motion picture capability. Compacts often have macro capability and zoom lenses but the zoom range is usually less than for bridge and DSLR cameras. Generally a contrast-detect autofocus system, using the image data from the live preview feed of the main imager, focuses the lens.
Typically, these cameras incorporate a nearly-silent leaf shutter into their lenses.
For lower cost and smaller size, these cameras typically use image sensors with a diagonal of approximately 6 mm, corresponding to a crop factor around 6. This gives them weaker low-light performance, greater depth of field, generally closer focusing ability, and smaller components than cameras using larger sensors.
Starting in 2011, some compact digital cameras can take 3D still photos. These 3D compact stereo cameras can capture 3D panoramic photos for play back on a 3D TV.[3] Some of these are rugged and waterproof, and some have GPS, compass, barometer and altimeter. [4]
Bridge cameras
Main article: Bridge camera
Bridge are higher-end digital cameras that physically and ergonomically resemble DSLRs and share with them some advanced features, but share with compacts the use of a fixed lens and a small sensor. Like compacts, most use live preview to frame the image. Their autofocus uses the same contrast-detect mechanism, but many bridge cameras have a manual focus mode, in some cases using a separate focus ring, for greater control. They originally "bridged" the gap between affordable point-and-shoot cameras and the then unaffordable earlier digital SLRs.Due to the combination of big physical size but a small sensor, many of these cameras have very highly specified lenses with large zoom range and fast aperture, partially compensating for the inability to change lenses. On some, the lens qualifies as superzoom. To compensate for the lesser sensitivity of their small sensors, these cameras almost always include an image stabilization system to enable longer handheld exposures.
These cameras are sometimes marketed as and confused with digital SLR cameras since the appearance is similar. Bridge cameras lack the reflex viewing system of DSLRs, are usually fitted with fixed (non-interchangeable) lenses (although some have a lens thread to attach accessory wide-angle or telephoto converters), and can usually take movies with sound. The scene is composed by viewing either the liquid crystal display or the electronic viewfinder (EVF). Most have a longer shutter lag than a true dSLR, but they are capable of good image quality (with sufficient light) while being more compact and lighter than DSLRs. High-end models of this type have comparable resolutions to low and mid-range DSLRs. Many of these cameras can store images in a Raw image format, or processed and JPEG compressed, or both. The majority have a built-in flash similar to those found in DSLRs.
In bright sun, the quality difference between a good compact camera and a digital SLR is minimal but bridgecams are more portable, cost less and have a similar zoom ability to dSLR. Thus a Bridge camera may better suit outdoor daytime activities, except when seeking professional-quality photos.[5]
In low light conditions and/or at ISO equivalents above 800, most bridge cameras (or megazooms) lack in image quality when compared to even entry level DSLRs. However, they do have one major advantage, often not appreciated:- their much larger depth of field due to the small sensor as compared to a DSLR, allowing larger apertures with shorter exposure times.
A 3D Photo Mode was introduced in 2011, whereby the camera automatically takes a second image from a slightly different perspective and provides a standard .MPO file for stereo display. [6]
Mirrorless interchangeable-lens camera
Main article: Mirrorless interchangeable-lens camera
In late 2008, a new type of camera emerged, combining the larger sensors and interchangeable lenses of DSLRs with the live-preview viewing system of compact cameras, either through an electronic viewfinder or on the rear LCD. These are simpler and more compact than DSLRs due to the removal of the mirror box, and typically emulate the handling and ergonomics of either DSLRs or compacts. The system is used by Micro Four Thirds, borrowing components from the Four Thirds DSLR system. The Ricoh GXR of 2009 puts the sensor and other electronic components in the interchangeable sensor–lens assembly or "camera unit," rather than in the camera body.[7]The Lumix G 12.5mm/F12 (H-FT012) is "3D" lens, using two lenses quite close together in one lens-module adaptor, compatible with the interchangeable-lens Panasonic Lumix DMC-GH2.[8]
Digital single lens reflex cameras
Main article: Digital single-lens reflex camera
Digital single-lens reflex cameras (DSLRs) are digital cameras based on film single-lens reflex cameras (SLRs). They take their name from their unique viewing system, in which a mirror reflects light from the lens through a separate optical viewfinder. In order to capture an image the mirror is flipped out of the way, allowing light to fall on the imager. Since no light reaches the imager during framing, autofocus is accomplished using specialized sensors in the mirror box itself. Most 21st century DSLRs also have a "live view" mode that emulates the live preview system of compact cameras, when selected.These cameras have much larger sensors than the other types, typically 18 mm to 36 mm on the diagonal (crop factor 2, 1.6, or 1). This gives them superior low-light performance, less depth of field at a given aperture, and a larger size.
They make use of interchangeable lenses; each major DSLR manufacturer also sells a line of lenses specifically intended to be used on their cameras. This allows the user to select a lens designed for the application at hand: wide-angle, telephoto, low-light, etc. So each lens does not require its own shutter, DSLRs use a focal-plane shutter in front of the imager, behind the mirror.
The mirror flipping out of the way at the moment of exposure makes a distinctive "clack" sound.
Digital rangefinders
Main article: Rangefinder camera#Digital rangefinder
A rangefinder is a user-operated optical mechanism to measure subject distance once widely used on film cameras. Most digital cameras measure subject distance automatically using electro-optical techniques, but it is not customary to say that they have a rangefinder.Line-scan camera systems
A line-scan camera is a camera device containing a line-scan image sensor chip, and a focusing mechanism. These cameras are almost solely used in industrial settings to capture an image of a constant stream of moving material. Unlike video cameras, line-scan cameras use a single array of pixel sensors, instead of a matrix of them. Data coming from the line-scan camera has a frequency, where the camera scans a line, waits, and repeats. The data coming from the line-scan camera is commonly processed by a computer, to collect the one-dimensional line data and to create a two-dimensional image. The collected two-dimensional image data is then processed by image-processing methods for industrial purposes.Line-scan technology is capable of capturing data extremely fast, and at very high image resolutions. Usually under these conditions, resulting collected image data can quickly exceed 100 MB in a fraction of a second. Line-scan-camera–based integrated systems, therefore are usually designed to streamline the camera's output in order to meet the system's objective, using computer technology which is also affordable.
Line-scan cameras intended for the parcel handling industry can integrate adaptive focusing mechanisms to scan six sides of any rectangular parcel in focus, regardless of angle, and size. The resulting 2-D captured images could contain, but are not limited to 1D and 2D barcodes, address information, and any pattern that can be processed via image processing methods. Since the images are 2-D, they are also human-readable and can be viewable on a computer screen. Advanced integrated systems include video coding, optical character recognition (OCR) and finish-line cameras for high speed sports.
Further information: Rotating line camera
Integration
Many devices include digital cameras built into or integrated into them. For example, mobile phones often include digital cameras; those that do are known as camera phones. Other small electronic devices (especially those used for communication) such as PDAs, laptops and BlackBerry devices often contain an integral digital camera, and most 21st century camcorders can also make still pictures.Due to the limited storage capacity and general emphasis on convenience rather than image quality, the vast majority of these integrated or converged devices store images in the lossy but compact JPEG file format.
Mobile phones incorporating digital cameras were introduced in Japan in 2001 by J-Phone. In 2003 camera phones outsold stand-alone digital cameras, and in 2006 they outsold all film-based cameras and digital cameras combined. These camera phones reached a billion devices sold in only five years, and by 2007 more than half of the installed base of all mobile phones were camera phones. Sales of separate cameras peaked in 2008. [9]
Integrated cameras tend to be at the very lowest end of the scale of digital cameras in technical specifications, such as resolution, optical quality, and ability to use accessories. With rapid development, however, the gap between mainstream compact digital cameras and camera phones is closing, and high-end camera phones are competitive with low-end stand-alone digital cameras of the same generation.
Conversion of film cameras to digital
When digital cameras became common, a question many photographers asked was whether their film cameras could be converted to digital. The answer was yes and no. For the majority of 35 mm film cameras the answer is no, the reworking and cost would be too great, especially as lenses have been evolving as well as cameras. For most a conversion to digital, to give enough space for the electronics and allow a liquid crystal display to preview, would require removing the back of the camera and replacing it with a custom built digital unit.
The major reason why affordable Digital camera backs never became available was that the manufacturers of sensors were identical or associated with camera manufacturers that were interested in selling new, rather than extending the life of old equipment. In fact, the coming of digital cameras was a very beneficial to the Japanese camera industry, which showed signs of stagnation in the late 80s due to market saturation. The new digital SLRs were for the main part purposely made not to be downward-compatible in accepting the world's vast inventory of momentarily near-useless high-quality SLR lenses even if of the same bayonet. This in spite of the fact that one major high-end manufacturer used to advertise his pre-digital optics as being "like money in the bank". As of 2011, no DSLR has appeared to take the very common M42-Lenses. Russian and Chinese manufacturers have not been able to make a DSLR of any sort: it remains to be seen if they will, with the availability of the new 16MP APS-C size sensor MT9H004 from the US-manufacturer Aptina.[citation needed]
Many early professional SLR cameras, such as the Kodak DCS series, were developed from 35 mm film cameras. The technology of the time, however, meant that rather than being digital "backs" the bodies of these cameras were mounted on large, bulky digital units, often bigger than the camera portion itself. These were factory built cameras, however, not aftermarket conversions.
A notable exception is the Nikon E2, followed by Nikon E3, using additional optics to convert the 35mm format to a 2/3 CCD-sensor.
A few 35 mm cameras have had digital camera backs made by their manufacturer, Leica being a notable example. Medium format and large format cameras (those using film stock greater than 35 mm), have a low unit production, and typical digital backs for them cost over $10,000. These cameras also tend to be highly modular, with handgrips, film backs, winders, and lenses available separately to fit various needs.
The very large sensor these backs use leads to enormous image sizes. For example Phase One's P45 39 MP image back creates a single TIFF image of size up to 224.6 MB, and even greater pixel counts are available. Medium format digitals such as this are geared more towards studio and portrait photography than their smaller DSLR counterparts; the ISO speed in particular tends to have a maximum of 400, versus 6400 for some DSLR cameras. (Canon EOS-1D Mark IV and Nikon D3S have ISO 12800 plus Hi-3 ISO 102400)
History
Main article: History of the camera#Digital Cameras
Steven Sasson as an engineer at Eastman Kodak invented and built the first digital camera using a charge-coupled device image sensor in 1975.[10][11]Image sensors
Further information: Image sensor
Image resolution
The resolution of a digital camera is often limited by the image sensor (typically a CCD or CMOS sensor chip) that turns light into discrete signals, replacing the job of film in traditional photography. The sensor is made up of millions of "buckets" that essentially count the number of photons that strike the sensor. This means that the brighter the image at a given point on the sensor, the larger the value that is read for that pixel. Depending on the physical structure of the sensor, a color filter array may be used which requires a demosaicing/interpolation algorithm. The number of resulting pixels in the image determines its "pixel count". For example, a 640x480 image would have 307,200 pixels, or approximately 307 kilopixels; a 3872x2592 image would have 10,036,224 pixels, or approximately 10 megapixels.
Image at left has a higher pixel count than the one to the right, but is still of worse spatial resolution.
Where such other factors limit the resolution, a greater pixel count does not improve it, but may rather make the digital images inconveniently large and/or exacerbate image noise. Many digital compact cameras are criticized for having excessive pixels. Sensors can be so small that their 'buckets' can easily overfill; again, resolution of a sensor can become greater than the camera lens could possibly deliver.
Demanding high quality and resolution (e.g. for use in professional photography), this count is an object of manufacturer competion. As of August 2011, the highest resolution available on the market is 80.1 MP.[12]
Since only a few aspect ratios are commonly used (mainly 4:3 and 3:2), the number of sensor sizes that are useful is limited. Furthermore, sensor manufacturers do not produce every possible sensor size, but take incremental steps in sizes. For example, in 2007 the three largest sensors (in terms of pixel count) used by Canon were the 21.1, 17.9, and 16.6 megapixel CMOS sensors.
Methods of image capture
The first method is often called single-shot, in reference to the number of times the camera's sensor is exposed to the light passing through the camera lens. Single-shot capture systems use either one CCD with a Bayer filter mosaic, or three separate image sensors (one each for the primary additive colors red, green, and blue) which are exposed to the same image via a beam splitter.
The second method is referred to as multi-shot because the sensor is exposed to the image in a sequence of three or more openings of the lens aperture. There are several methods of application of the multi-shot technique. The most common originally was to use a single image sensor with three filters (once again red, green and blue) passed in front of the sensor in sequence to obtain the additive color information. Another multiple shot method is called Microscanning. This technique utilizes a single CCD with a Bayer filter but actually moved the physical location of the sensor chip on the focus plane of the lens to "stitch" together a higher resolution image than the CCD would allow otherwise. A third version combined the two methods without a Bayer filter on the chip.
The third method is called scanning because the sensor moves across the focal plane much like the sensor of a desktop scanner. Their linear or tri-linear sensors utilize only a single line of photosensors, or three lines for the three colors. In some cases, scanning is accomplished by moving the sensor e.g. when using Color co-site sampling or rotate the whole camera; a digital rotating line camera offers images of very high total resolution.
The choice of method for a given capture is determined largely by the subject matter. It is usually inappropriate to attempt to capture a subject that moves with anything but a single-shot system. However, the higher color fidelity and larger file sizes and resolutions available with multi-shot and scanning backs make them attractive for commercial photographers working with stationary subjects and large-format photographs.
Dramatic improvements in single-shot cameras and raw image file processing at the beginning of the 21st century made single shot, CCD-based cameras almost completely dominant, even in high-end commercial photography. CMOS-based single shot cameras remained somewhat common.
Filter mosaics, interpolation, and aliasing
Cameras that use a beam-splitter single-shot 3CCD approach, three-filter multi-shot approach, Color co-site sampling or Foveon X3 sensor do not use anti-aliasing filters, nor demosaicing.
Firmware in the camera, or a software in a raw converter program such as Adobe Camera Raw, interprets the raw data from the sensor to obtain a full color image, because the RGB color model requires three intensity values for each pixel: one each for the red, green, and blue (other color models, when used, also require three or more values per pixel). A single sensor element cannot simultaneously record these three intensities, and so a color filter array (CFA) must be used to selectively filter a particular color for each pixel.
The Bayer filter pattern is a repeating 2×2 mosaic pattern of light filters, with green ones at opposite corners and red and blue in the other two positions. The high proportion of green takes advantage of properties of the human visual system, which determines brightness mostly from green and is far more sensitive to brightness than to hue or saturation. Sometimes a 4-color filter pattern is used, often involving two different hues of green. This provides potentially more accurate color, but requires a slightly more complicated interpolation process.
The color intensity values not captured for each pixel can be interpolated (or guessed) from the values of adjacent pixels which represent the color being calculated.
Sensor size and angle of view
Cameras with digital image sensors that are smaller than the typical 35mm film size has a smaller field or angle of view when used with a lens of the same focal length. This is because angle of view is a function of both focal length and the sensor or film size used.
If the digital sensor has approximately the same resolution (effective pixels per unit area) as the 35mm film surface (24 x 36 mm), then the result is similar to taking the image from the film camera and cutting it down (cropping) to the size of the sensor. For an APS-C size sensor, this would be a reduction to the center 62.5% of the image. The cheaper, non-SLR models of digital cameras typically use much smaller sensor sizes and the reduction would be greater.
If the digital sensor has a higher or lower density of pixels per unit area than the film equivalent, then the amount of information captured differs correspondingly. While resolution can be estimated in pixels per unit area, the comparison is complex since most types of digital sensor record only a single colour at each pixel location, and different types of film have different effective resolutions. There are various trade-offs involved, since larger sensors are more expensive to manufacture and require larger lenses, while sensors with higher numbers of pixels per unit area are likely to suffer higher noise levels.
For these reasons, it is possible to obtain cheap digital cameras with sensor sizes much smaller than 35mm film, but with high pixel counts, that can still produce high-resolution images. Such cameras are usually supplied with lenses that would be classed as extremely wide angle on a 35mm camera, and that can also be smaller size and less expensive, since there is a smaller sensor to illuminate. For example, a camera with a 1/1.8" sensor has a 5.0x field of view crop, and so a hypothetical 5-50mm zoom lens produces images that look similar (again the differences mentioned above are important) to those produced by a 35mm film camera with a 25–250mm lens, while being much more compact than such a lens for a 35mm camera since the imaging circle is much smaller.
This can be useful if extra telephoto reach is desired, as a certain lens on an APS sensor produces an image equivalent to a significantly longer lens on a 35mm film camera shot at the same distance from the subject, the equivalent length of which depends on the camera's field of view crop. This is sometimes referred to as the focal length multiplier, but the focal length is a physical attribute of the lens and not the camera system itself. The disadvantage of this is that wide angle photography is made somewhat more difficult, as the smaller sensor effectively and undesirably reduces the captured field of view. Some methods of compensating for this or otherwise producing much wider digital photographs involve using a fisheye lens and "defishing" the image in post processing to simulate a rectilinear wide angle lens.
Full-frame digital SLRs, that is, those with sensor size matching a frame of 35mm film, include Canon 1Ds and 5D series, Kodak Pro DCS-14n, Nikon D3 line and Contax N Digital. There are very few digital cameras with sensors that can approach the resolution of larger-format film cameras, with the possible exception of the Mamiya ZD (22MP) and the Hasselblad H3D series of DSLRs (22 to 39 MP).
Common values for field of view crop in DSLRs include 1.3x for some Canon (APS-H) sensors, 1.5x for Sony APS-C sensors used by Nikon, Pentax and Konica Minolta and for Fujifilm sensors, 1.6 (APS-C) for most Canon sensors, ~1.7x for Sigma's Foveon sensors and 2x for Kodak and Panasonic 4/3" sensors currently used by Olympus and Panasonic. Crop factors for non-SLR consumer compact and bridge cameras are larger, frequently 4x or more
Further information: Image sensor format
| Table of sensor sizes [14] | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type | Width (mm) | Height (mm) | Size (mm²) | |||||||||||
| 1/3.6" | 4.00 | 3.00 | 12.0 | |||||||||||
| 1/3.2" | 4.54 | 3.42 | 15.5 | |||||||||||
| 1/3" | 4.80 | 3.60 | 17.3 | |||||||||||
| 1/2.7" | 5.37 | 4.04 | 21.7 | |||||||||||
| 1/2.5" | 5.76 | 4.29 | 24.7 | |||||||||||
| 1/2.3" | 6.16 | 4.62 | 28.5 | |||||||||||
| 1/2" | 6.40 | 4.80 | 30.7 | |||||||||||
| 1/1.8" | 7.18 | 5.32 | 38.2 | |||||||||||
| 1/1.7" | 7.60 | 5.70 | 43.3 | |||||||||||
| 2/3" | 8.80 | 6.60 | 58.1 | |||||||||||
| 1" | 12.8 | 9.6 | 123 | |||||||||||
| 4/3" | 18.0 | 13.5 | 243 | |||||||||||
| APS-C | 25.1 | 16.7 | 419 | |||||||||||
| 35 mm | 36 | 24 | 864 | |||||||||||
| Back | 48 | 36 | 1728 | |||||||||||
Connectivity
Transferring photos
Many digital cameras can connect directly to a computer to transfer data:- Early cameras used the PC serial port. USB is now the most widely used method (most cameras are viewable as USB mass storage), though some have a FireWire port. Some cameras use USB PTP mode for connection instead of USB MSC; some offer both modes.
- Other cameras use wireless connections, via Bluetooth or IEEE 802.11 Wi-Fi, such as the Kodak EasyShare One.
- Cameraphones and some high-end stand-alone digital cameras also use cellular networks to connect for sharing images. The most common standard on cellular networks is the MMS Multimedia Messaging Service, commonly called "picture messaging". The second method with smartphones is to send a picture as an email attachment. Many cameraphones do not support email, so this is less common.
Printing photos
Many modern cameras support the PictBridge standard, which allows them to send data directly to a PictBridge-capable computer printer without the need for a computer.Wireless connectivity can also provide for printing photos without a cable connection.
Polaroid has introduced a printer integrated into its digital camera which creates a small, printed copy of a photo. This is reminiscent of the original instant camera, popularized by Polaroid in 1975.[15]
Displaying photos
Many digital cameras include a video output port. Usually sVideo, it sends a standard-definition video signal to a television, allowing the user to show one picture at a time. Buttons or menus on the camera allow the user to select the photo, advance from one to another, or automatically send a "slide show" to the TV.HDMI has been adopted by many high-end digital camera makers, to show photos in their high-resolution quality on an HDTV.
In January 2008, Silicon Image announced a new technology for sending video from mobile devices to a television in digital form. MHL sends pictures as a video stream, up to 1080p resolution, and is compatible with HDMI.[16]
Some DVD recorders and television sets can read memory cards used in cameras; alternatively several types of flash card readers have TV output capability.
Modes
Many digital cameras have preset modes for different applications. Within the constraints of correct exposure various parameters can be changed, including exposure, aperture, focusing, light metering, white balance, and equivalent sensitivity. For example a portrait might use a wider aperture to render the background out of focus, and would seek out and focus on a human face rather than other image content.Image data storage
Digital cameras have computers inside, hence have internal memory, and many cameras can use some of this internal memory for a limited capacity for pictures that can be transferred to or from the card or through the camera's connections.
A few cameras use some other form of removable storage such as Microdrives (very small hard disk drives), CD single (185 MB), and 3.5" floppy disks. Other unusual formats include:
- Onboard flash memory — Cheap cameras and cameras secondary to the device's main use (such as a camera phone)
- PC Card hard drives — early professional cameras (discontinued)
- Thermal printer — known only in one model of camera that printed images immediately rather than storing
- Mini CD (left)
- Microdrive (CF-II)
File formats
Main article: Image file formats
The Joint Photography Experts Group standard (JPEG) is the most common file format for storing image data. Other file types include Tagged Image File Format (TIFF) and various Raw image formats.Many cameras, especially professional or DSLR cameras, support a Raw image format. A raw image is the unprocessed set of pixel data directly from the camera's sensor. They are often saved in formats proprietary to each manufacturer, such as NEF for Nikon, CRW or CR2 for Canon, and MRW for Minolta. Adobe Systems has released the DNG format, a royalty free raw image format which has been adopted by at least 10 camera manufacturers.
Raw files initially had to be processed in specialized image editing programs, but over time many mainstream editing programs, such as Google's Picasa, have added support for raw images. Editing raw format images allows more flexibility in settings such as white balance, exposure compensation, color temperature, and so on. In essence raw format allows the photographer to make major adjustments without losing image quality that would otherwise require retaking the picture.
Formats for movies are AVI, DV, MPEG, MOV (often containing motion JPEG), WMV, and ASF (basically the same as WMV). Recent formats include MP4, which is based on the QuickTime format and uses newer compression algorithms to allow longer recording times in the same space.
Other formats that are used in cameras but not for pictures are the Design Rule for Camera Format (DCF), an ISO specification for the camera's internal file structure and naming, and Digital Print Order Format (DPOF), which dictates what order images are to be printed in and how many copies.
Most cameras include Exif data that provides metadata about the picture. Exif data may include aperture, exposure time, focal length, date and time taken, and location.
Batteries
Two broad types of batteries are in use for digital cameras.
Off-the-shelf
The first type of battery for digital cameras conform to an established off-the-shelf form factor, most commonly AA, CR2, or CR-V3 batteries, with AAA batteries in a handful of cameras. The CR2 and CR-V3 batteries are lithium based, and intended for single use. They are also commonly seen in camcorders. AA batteries are the most common; however, the non-rechargeable alkaline batteries supplied with low-end cameras are capable of providing enough power for only a very short time in most cameras. They may serve satisfactorily in cameras that are only occasionally used.Consumers with more than an occasional need use AA Nickel metal hydride batteries (NiMH) instead, which provide an adequate amount of power and are rechargeable. NIMH batteries do not provide as much power per volume as lithium ion batteries, and they also tend to discharge when not used. To get same power, NiMH Rechargeable battery takes up to two times in volume compare to Li-on Rechargeable Battery, by weight NiMH Rechargeable Battery is three to five times heavier, but by price NiMH Rechargeable Battery is only a half compare to Li-on Rechargeable Battery. Please see Wikipedia: Table of rechargeable battery technologies in Rechargeable battery. They are available in various ampere-hour (Ah) or milli-ampere-hour (mAh) ratings, which affects how long they last in use. Typically mid-range consumer models and some low end cameras use off-the-shelf batteries; only a very few DSLR cameras accept them (for example, Sigma SD10). Rechargeable RCR-V3 lithium-ion batteries are also available as an alternative to non-rechargeable CR-V3 batteries. Cameras, especially earlier ones made for AA-size batteries assumed that these would be of the non-rechargeable, preferably alkaline manganese type delivering 1.5 volts per cell. Rechargeable NiCd or NiMH cells only deliver 1.2 volts, which means that many such cameras will only operate for a short time or not at all even with new and newly charged 1.2 volt units. A portable ultra-high-endurance external power-supply for the shoulder bag to operate older 6 volt cameras can be made up of five 1.2 volt C-size cells which can be either NiCd or NiMH, with a cable and 4mm DC-plug.
Proprietary
The second type of battery for digital cameras is proprietary battery formats. These are built to a manufacturer's custom specifications, and can be either aftermarket replacement parts or OEM. Almost all proprietary batteries are lithium ion. While they only accept a certain number of recharges before the battery life begins degrading (typically up to 500 cycles), they provide considerable performance for their size. A result is that at the two ends of the spectrum both high end professional cameras and low end consumer models tend to use lithium ion batteries.Digital camera backs
Main article: digital camera back
In the industrial and high-end professional photography market, some camera systems utilize modular (removable) image sensors. For example, some medium format SLR cameras, such as the Mamiya 645D series, allow installation of either a digital camera back or a traditional photographic film back.- Area array
- CCD
- CMOS
- Linear array
- CCD (monochrome)
- 3-strip CCD with color filters
- Single-shot
- Multi-shot (three-shot, usually)
Some other camera backs use CCD arrays similar to typical cameras. These are called single-shot backs.
Since it is much easier to manufacture a high-quality linear CCD array with only thousands of pixels than a CCD matrix with millions, very high resolution linear CCD camera backs were available much earlier than their CCD matrix counterparts. For example, you could buy an (albeit expensive) camera back with over 7,000 pixel horizontal resolution in the mid-1990s. However, as of 2004, it is still difficult to buy a comparable CCD matrix camera of the same resolution. Rotating line cameras, with about 10,000 color pixels in its sensor line, are able, as of 2005, to capture about 120,000 lines during one full 360 degree rotation, thereby creating a single digital image of 1,200 Megapixels.
Most modern digital camera backs use CCD or CMOS matrix sensors. The matrix sensor captures the entire image frame at once, instead of incrementing scanning the frame area through the prolonged exposure. For example, Phase One produces a 39 million pixel digital camera back with a 49.1 x 36.8 mm CCD in 2008. This CCD array is a little smaller than a frame of 120 film and much larger than a 35 mm frame (36 x 24 mm). In comparison, consumer digital cameras use arrays ranging from 36 x 24 mm (full frame on high end consumer DSLRs) to 7.2 x 5.3 mm (on point and shoot cameras) CMOS sensor.
At present, there are relatively few complete digital SLR cameras with sensors large enough to compete with the image detail offered by medium to large format film cameras. Phase One, Mamiya, and Hasselblad in 2011 manufacture medium format digital devices that can capture 30MP up to 80MP. The units tend to be quite large and expensive. Additionally, because of their high build quality and lack of moving parts, they tend to be quite long lasting and are prominent on the used market.[17]
See also
digital camera
Rivaling not only the new Sony NEX-C3, but also Panasonic's own deluxe digicam the LX5, the Panasonic GF3 brings the Micro Four Thirds camp a new definition of small. As did Sony, to achieve this size, Panasonic had to rethink much of the control system, as shrinking bodies leave little room for luxuries like mode dials, switches, and buttons. As a result, there's a learning curve to using the GF3, but for those seeking a very small compact system camera, the Lumix GF3 has a lot to offer in a very small body.
Along with the step-down in size, Panasonic saw fit to keep the resolution of the GF3's sensor to 12-megapixels, yet they're quick to add that the same sensor improvements that impressed us in the 16-megapixel G3 are included in the GF3. Also of note, the GF3 supports Full HD video, that's 1,920 x 1,080 in AVCHD format.
The main first impression one gets from the Lumix GF3 is that it's tiny. Especially with the 14mm f/2.5 lens attached, it really does dip down into digicam territory. It's a little taller than an LX5, but less wide; thickness of course varies with the lens mounted, but it's not far off, either. We have a few comparison shots below, pitting the GF3 against the Sony NEX-C3 and Lumix G3. It's a close call with the Sony, but the GF3 makes the small, feature-rich G3 look big again. The Canon G12 and Nikon P7000, already larger than the GF2, can consider the gauntlet thrown down.
Compared to the GF2, the GF3 is smaller in width and height, but not thickness. The Panasonic GF3 measures 4.2 x 2.6 x 1.3 inches (108 x 67 x 33mm), versus 4.4 x 2.7 x 1.3 inches (113 x 68 x 33mm) on the GF2, and weight is also reduced to 9.3 ounces (264g), from the GF2's 11.3 ounces (319g). Put another way, the GF3 is 16.7 percent smaller and 16.2 percent lighter than the GF2, according to Panasonic.
The Panasonic GF3 is indeed light, but still feels solid, and a little better balanced than the NEX-C3, with the lens positioned just a tad closer to the center. The grip is scanty, at best only supporting a two finger hold. Similar to the grip on the G3 in shape, it's smaller, and requires extra care to avoid dropping the tiny GF3. It might be a little better as a grip than the one on the GF2, though. I recommend at least a wrist strap with the Panasonic GF3, if not use of the included neckstrap. I'm thankful they went with metal loop mounts for that strap, by the way, as the cloth-to-metal interface is prone to less noise than the metal-to-metal D-ring approach.
Best described as clean and simple, the GF3's front is a contrast to the more boxy GF2, with sloping shoulders and more gradual curves. A bright chrome ring surrounds the lens mount, adding the unusual effect of making the lenses look even smaller, like they are smaller than the mount itself. An AF-assist lamp (which doubles as a self-timer indicator) peeks out from the upper right of the lens mount, something too many SLRs lack.
From left to right, the top features a monaural microphone, a speaker, a small pop-up flash, the Intelligent Auto button, Shutter button, Record button, and a sliding Power switch. The mono mic is a step down from the GF2 for video, and the lack of a hot shoe in addition to a pop-up flash is also a change from the last generation. At this size, Panasonic said they didn't see a lot of people adopting external flashes, so they were content to delete the hot shoe for lower weight and smaller size. That still leaves out the option of an optical or electronic accessory viewfinder, for whatever it's worth.
While the GF2 had a total of 11 control buttons (not counting the flash pop-up button), the GF3 reduces the count to 10: Intelligent Auto, Shutter, Record, Playback, EV, White Balance, AF-point, Drive, Menu/Set, and Quick Menu/Function (the thumb-operated rear dial also served as a button on the GF2). You can set the Function button to activate 15 different things, but then you lose the Quick Menu: AF/AE Lock, Preview, Photo Style, Aspect Ratio, Quality, Focus mode, Metering mode, Flash, ISO Sensitivity, ISO Limit Set, Ex. Tele Conv., Burst Rate, Auto Bracket, Guide Line, and Record Area. Mode and Display settings are made via the LCD's touchscreen overlay. Pressing the onscreen Display button, which appears in the lower right corner, cycles through available modes, and pressing the Mode icon in the upper left corner brings up a circular display of nine bubbles, each with a mode. Turning the physical rotary dial surrounding the navigation disk moves from bubble to bubble, or you can simply press one of the bubbles with your finger.
The 3-inch LCD has a 460,000-dot display that's sharp and vibrant. Unlike the G3 and Sony NEX-C3, the display does not articulate (tilt or swivel), but integrated touch focus features somewhat make up for that omission.
Since a big part of the Panasonic GF3 is its small size, we'll go straight into two of the more interesting side-by-side comparisons.
Sensor and processor. The Panasonic GF3 features a 12.1 megapixel Micro Four Thirds-format image sensor whose output is handled by a Venus Engine FHD image processor. It's said to have the same image processing capabilities as the recently-announced Lumix G3, although the GF3's Live MOS image sensor has a total resolution of 13.06 megapixels, in place of the 16.68 megapixel chip used in the G3. Base sensitivity for the GF3's imager is ISO 160 equivalent, while maximum sensitivity is unchanged from that of the GF2, at ISO 6,400 equivalent.
Panasonic's full range of advanced features is supported by the processor, including Intelligent Auto, Intelligent Resolution, and Intelligent Dynamic Range Control. (See the Image Quality page to see how these features work.)
Performance. The GF3 bests its predecessor by quite some margin in terms of burst shooting performance, and given the earlier camera's relatively sedate performance, that would be a very welcome change. Panasonic rates the GF3 as capable of shooting some 3.8 frames per second, some 19% faster than the company-supplied 3.2 fps figure for the GF2. In our own lab testing, the GF3 proved capable of 3.5 fps in High Speed mode. JPEG shooters will be happy to see that burst depth is still restricted only by available space and battery life when shooting typical subjects, given a fast enough flash card. We managed 20 JPEGs in a high-speed burst with our difficult-to-compress target. For Raw shooters, though, burst depth is unfortunately still quite abbreviated, at just seven frames. In our testing, we got at most five Raw frames before the GF3 slowed down.
Optics. Around twenty lens models are now available for Micro Four Thirds format cameras, and Panasonic itself offers a healthy selection of both prime and zoom lenses, as well as its unusual 3D lens, all compatible with the GF3. As you'd expect, a Supersonic Wave Filter dust reduction system is included, to minimize the effects of dust ingested during operation.
Touch-panel display. An important difference between the GF3 and its predecessor is the lack of any provision for an external viewfinder. With no accessory port on the GF3's body, all interaction is handled through its 3.0-inch touch panel LCD display, which appears to be unchanged from that featured in the GF2. The Lumix GF3's LCD has a total resolution of 460,000 dots, which equates to somewhere in the region of 153,600 pixels, commonly known as HVGA (Half-size VGA). Each pixel comprises adjacent red, green, and blue-colored dots. The panel has a 3:2 aspect ratio, approximately 100% coverage, seven-step brightness / color adjustment, and a wide viewing angle (although Panasonic doesn't specify the actual horizontal / vertical viewing range).
Focusing. Like the GF2 before it, the GF3 offers up a 23-point TTL contrast detection autofocusing system, as well as an autofocus assist lamp that helps when focusing in low ambient lighting conditions. As well as multi-point focusing, the GF3 also provides single, pinpoint, tracking, and face detection autofocus modes. In single-point mode, the focus point can be placed anywhere within the image frame, by simply dragging it on the touch-panel display. Autofocus speed is said to be similar to that of the Lumix G3 and GH2 models, and our test results agree.
Of course, you can also focus manually, and the GF3 offers a manual focus assist zoom that enlarges the display around the focus point, allowing precise focus tuning. Three zoom levels are available -- either 4x, 5x, or 10x. As in the G3, the lowest zoom level shows an enlargement only at the center of the screen, overlaid on the full image, providing a reasonably intuitive way to focus while retaining your desired framing.
Exposure. The Lumix GF3 offers still image shutter speeds ranging from 1/4,000 to 60 seconds. Images are metered with the Live MOS image sensor, using a 144-segment multi-pattern metering system, and the GF3 also provides both center-weighted and spot metering modes. +/-3.0 EV of exposure compensation is available, set in 1/3 EV steps, and the metering system has a working range of EV 0-18 (with an f/2.0 lens at ISO 100 equivalent.)
Flash. Like the GF2 before it, the Panasonic GF3 is said to be the smallest interchangeable-lens camera yet announced that includes a built-in flash strobe. The GF3's built-in popup flash has been relocated directly above the central axis of the lens, a position previously occupied by the hot shoe on the GF2, and this hints at an important omission. Unlike its predecessor, the Panasonic GF3 has no provision for external flash strobes. There's no hot shoe, and since the external accessory connector has also been removed, there's no possibility of a proprietary flash accessory being offered, either.
This change makes the built-in flash doubly important, and unfortunately, it still has a rather modest guide number of just 6.3 meters at ISO 160 equivalent. With that said, being a relatively compact camera, it's likely that an external flash would get left at home anyway, so perhaps the lack of external flash connectivity won't prove much of an issue.
Creative controls. As in the G3, Panasonic has retained its two main creative control function groups from the earlier GF2 model in the GF3, but with new names for each.
The earlier My Color mode is now known as Creative Control, and provides access to six effects, one more than in the G3 but two less than the GF2. Choices are Expressive (pop-art style), Retro (soft, tarnished effect), High Key (brighter image), Sepia, High Dynamic (localized color and contrast enhancement), and Miniature Effect (linear graduated blur towards the edges of the image).
The Film Mode function has also been renamed to Photo Style. This offers a selection of six presets, plus a custom mode, each of which can be tweaked in terms of contrast, sharpness, saturation (except in Monochrome mode, where it is replaced with a color tone adjustment), and noise reduction. Presets include Standard, Vivid, Natural, Monochrome, Scenery, and Portrait.
There are also 17 Scene modes that help amateurs get the results they're looking for without the need to understand shutter speeds, apertures, and the like, as well as Intelligent Auto and Intelligent Auto+ modes that both offer maximum ease of use, but differ in their level of control over the look of images.
Video. The GF3's movie capture capabilities are very similar to those of the GF2, but with a number of important changes. The GF3 still provides for Full HD (1,080i / 1,920 x 1,080 pixel) or 720p (1,280 x 720 pixel) video capture at 17Mbps in AVCHD format, as well as for Motion JPEG capture at 720p resolution or below. Recording rates are likewise unchanged -- NTSC models offer either 30 frames per second for Motion JPEG, 60 frames per second for 720p AVCHD, or 60 fields per second for 1080i AVCHD, all captured from 30 frames per second sensor data. PAL models are 50i for 1080i AVCHD and 50p for 720p AVCHD, from 25 frames per second sensor data.
The differences are threefold. Panasonic has dropped the 13Mbps "FH" and "F" options for AVCHD format, dropped the non-standard 848 x 480 pixel WVGA video capture mode, and replaced the GF2's stereo internal microphone with a monaural mic.
Exposure during video recording is fully automatic, though aperture can be adjusted while recording using the Defocus Control slider in either Intelligent Auto mode, and a flicker reduction feature lets you force the shutter speed to 1/50, 1/60, 1/100, or 1/120 second. Exposure compensation and white balance can be adjusted before recording starts in Intelligent Auto+ mode. Creative Control effects, Photo Styles, and 11 scene modes are also available for videos.
Of course, continuous autofocus is available during movies, complete with Touch AF. Other video recording features include a wind cut filter with four settings, and the mic's sensitivity can be adjusted to four levels. See the Motion Picture menu animation above right for additional features and settings.
Connectivity. The Lumix GF3 includes a mini HDMI Type C high-definition video output with VIERA Link compatibility, which allows the camera to be controlled by the remote control of a Panasonic VIERA Link-enabled HDTV. (VIERA Link is Panasonic's brandname for the HDMI Consumer Electronics Control standard, although compatibility with devices made by other companies is not guaranteed.)
The GF3 also includes a proprietary connector that provides for both USB 2.0 High Speed data transfer, and standard definition NTSC composite video output with monaural audio output. The USB port has PTP (for PictBridge compatible printers) and Mass Storage modes.
Storage. The Panasonic GF3 stores its data on Secure Digital cards, including the latest generation SDHC and SDXC types. As well as storing still images in JPEG compressed format, the G3 can also write RAW files, either alone or alongside a JPEG copy of each image. When using Panasonic's unusual 3D lens, the GF3 saves images in MPO (Multi Picture Object) format, with each MPO file containing two JPEG images with differing perspective. As noted previously, movies can be stored with either AVCHD or Motion JPEG compression, depending on the resolution.
Power. The Panasonic GF3 draws power from a proprietary 7.2V, 940mAh battery pack rated as good for 320 shots on a charge when using the 14-42mm lens, based on CIPA testing standards. With the 14mm lens, this climbs just slightly, to 340 images, as the 14mm lens lacks optical image stabilization. That's a slight improvement compared to the GF2's 300 and 320 shots with the same lenses. Maximum battery life during video capture has also improved, up from 120 minutes with the company's 14-42mm lens, to 130 minutes with the same lens. The Lumix GF3's battery/card door features a covered pass-through, for use with optional DC coupler and AC adapter.
Along with the step-down in size, Panasonic saw fit to keep the resolution of the GF3's sensor to 12-megapixels, yet they're quick to add that the same sensor improvements that impressed us in the 16-megapixel G3 are included in the GF3. Also of note, the GF3 supports Full HD video, that's 1,920 x 1,080 in AVCHD format.The main first impression one gets from the Lumix GF3 is that it's tiny. Especially with the 14mm f/2.5 lens attached, it really does dip down into digicam territory. It's a little taller than an LX5, but less wide; thickness of course varies with the lens mounted, but it's not far off, either. We have a few comparison shots below, pitting the GF3 against the Sony NEX-C3 and Lumix G3. It's a close call with the Sony, but the GF3 makes the small, feature-rich G3 look big again. The Canon G12 and Nikon P7000, already larger than the GF2, can consider the gauntlet thrown down.
Compared to the GF2, the GF3 is smaller in width and height, but not thickness. The Panasonic GF3 measures 4.2 x 2.6 x 1.3 inches (108 x 67 x 33mm), versus 4.4 x 2.7 x 1.3 inches (113 x 68 x 33mm) on the GF2, and weight is also reduced to 9.3 ounces (264g), from the GF2's 11.3 ounces (319g). Put another way, the GF3 is 16.7 percent smaller and 16.2 percent lighter than the GF2, according to Panasonic.
The Panasonic GF3 is indeed light, but still feels solid, and a little better balanced than the NEX-C3, with the lens positioned just a tad closer to the center. The grip is scanty, at best only supporting a two finger hold. Similar to the grip on the G3 in shape, it's smaller, and requires extra care to avoid dropping the tiny GF3. It might be a little better as a grip than the one on the GF2, though. I recommend at least a wrist strap with the Panasonic GF3, if not use of the included neckstrap. I'm thankful they went with metal loop mounts for that strap, by the way, as the cloth-to-metal interface is prone to less noise than the metal-to-metal D-ring approach.
Best described as clean and simple, the GF3's front is a contrast to the more boxy GF2, with sloping shoulders and more gradual curves. A bright chrome ring surrounds the lens mount, adding the unusual effect of making the lenses look even smaller, like they are smaller than the mount itself. An AF-assist lamp (which doubles as a self-timer indicator) peeks out from the upper right of the lens mount, something too many SLRs lack.
From left to right, the top features a monaural microphone, a speaker, a small pop-up flash, the Intelligent Auto button, Shutter button, Record button, and a sliding Power switch. The mono mic is a step down from the GF2 for video, and the lack of a hot shoe in addition to a pop-up flash is also a change from the last generation. At this size, Panasonic said they didn't see a lot of people adopting external flashes, so they were content to delete the hot shoe for lower weight and smaller size. That still leaves out the option of an optical or electronic accessory viewfinder, for whatever it's worth.
While the GF2 had a total of 11 control buttons (not counting the flash pop-up button), the GF3 reduces the count to 10: Intelligent Auto, Shutter, Record, Playback, EV, White Balance, AF-point, Drive, Menu/Set, and Quick Menu/Function (the thumb-operated rear dial also served as a button on the GF2). You can set the Function button to activate 15 different things, but then you lose the Quick Menu: AF/AE Lock, Preview, Photo Style, Aspect Ratio, Quality, Focus mode, Metering mode, Flash, ISO Sensitivity, ISO Limit Set, Ex. Tele Conv., Burst Rate, Auto Bracket, Guide Line, and Record Area. Mode and Display settings are made via the LCD's touchscreen overlay. Pressing the onscreen Display button, which appears in the lower right corner, cycles through available modes, and pressing the Mode icon in the upper left corner brings up a circular display of nine bubbles, each with a mode. Turning the physical rotary dial surrounding the navigation disk moves from bubble to bubble, or you can simply press one of the bubbles with your finger.
The 3-inch LCD has a 460,000-dot display that's sharp and vibrant. Unlike the G3 and Sony NEX-C3, the display does not articulate (tilt or swivel), but integrated touch focus features somewhat make up for that omission.
Since a big part of the Panasonic GF3 is its small size, we'll go straight into two of the more interesting side-by-side comparisons.
Panasonic GF3 size comparisons
Panasonic GF3 vs Sony NEX-C3
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| Panasonic was clearly aiming for the NEX-5 when they spec'd the GF3's dimensions, which explains Sony's move to a smaller 3-series body with the NEX-C3. The hump on top of the GF3 boasts of its small size, just as the hump on the bottom of the NEX-5 did, even if it does make the GF3 a little taller. Sony's design offers a grip for at least one more finger than the GF3's provides. |
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| Panasonic's choice of a smaller body for their kit lens helps the GF3 look a lot smaller. The 14mm lens provides a view equivalent to a 28mm lens, while the Sony's 16mm kit equates to about 24mm, a good deal wider. The NEX-C3 includes front-facing stereo speakers, while the GF3's is mono, but the GF3 also has a pop-up flash, an included, but not integrated accessory on the NEX-C3. Both feature simple power switches and easy access to dedicated Movie Record buttons. |
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| Since both are offered in two kit configurations, we included the zooms as well. Panasonic's design is equivalent to 28-84mm, while the Sony covers 27-82.5mm. Both are optically stabilized. |
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| Sony's control layout is even more simple than the GF3's, but both rely heavily on the LCD to drive the interface. The NEX-C3 has the advantage of a tilting LCD, while the GF3 is slightly less wide. Of course, there's also the resolution difference of 12 versus 16 megapixels. It's not really so important to most, but it's worth mentioning just in case. |
Panasonic GF3 vs Panasonic G3
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| We thought the Lumix G3 quite small until the GF3 arrived just a few weeks later. Both have their place in this market, to be sure. From the front the major differences are a considerably smaller grip on one than the other, and a whole lot more flash potential on the G3, as it still includes a hot shoe. |
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| The Mode dial, stereo speakers, and hot shoe again stand out as major advantages on the G3, but that huge protruding EVF is both a benefit and a hindrance, making the G3 noticeably thicker, and thus harder to put in a pocket or camera bag. |
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| It's tempting to call the Panasonic GF3 "the G3 stripped down to essentials," and we could were it not for the difference in sensor resolution (again, 12 versus 16 megapixels). The tilt/swivel LCD is the obvious major difference on the back, and there's only one additional button on the G3, namely the DISP/Fn1 button on the back. The LVF/LCD button and Record button are also present, but the former isn't needed on the GF3 and the latter is on the top deck. Both have touchscreen interfaces, but the GF3 relies on it more heavily than the G3. |
Panasonic GF3 Technical Info
Panasonic's full range of advanced features is supported by the processor, including Intelligent Auto, Intelligent Resolution, and Intelligent Dynamic Range Control. (See the Image Quality page to see how these features work.)
Performance. The GF3 bests its predecessor by quite some margin in terms of burst shooting performance, and given the earlier camera's relatively sedate performance, that would be a very welcome change. Panasonic rates the GF3 as capable of shooting some 3.8 frames per second, some 19% faster than the company-supplied 3.2 fps figure for the GF2. In our own lab testing, the GF3 proved capable of 3.5 fps in High Speed mode. JPEG shooters will be happy to see that burst depth is still restricted only by available space and battery life when shooting typical subjects, given a fast enough flash card. We managed 20 JPEGs in a high-speed burst with our difficult-to-compress target. For Raw shooters, though, burst depth is unfortunately still quite abbreviated, at just seven frames. In our testing, we got at most five Raw frames before the GF3 slowed down.
Optics. Around twenty lens models are now available for Micro Four Thirds format cameras, and Panasonic itself offers a healthy selection of both prime and zoom lenses, as well as its unusual 3D lens, all compatible with the GF3. As you'd expect, a Supersonic Wave Filter dust reduction system is included, to minimize the effects of dust ingested during operation.
Touch-panel display. An important difference between the GF3 and its predecessor is the lack of any provision for an external viewfinder. With no accessory port on the GF3's body, all interaction is handled through its 3.0-inch touch panel LCD display, which appears to be unchanged from that featured in the GF2. The Lumix GF3's LCD has a total resolution of 460,000 dots, which equates to somewhere in the region of 153,600 pixels, commonly known as HVGA (Half-size VGA). Each pixel comprises adjacent red, green, and blue-colored dots. The panel has a 3:2 aspect ratio, approximately 100% coverage, seven-step brightness / color adjustment, and a wide viewing angle (although Panasonic doesn't specify the actual horizontal / vertical viewing range).
Focusing. Like the GF2 before it, the GF3 offers up a 23-point TTL contrast detection autofocusing system, as well as an autofocus assist lamp that helps when focusing in low ambient lighting conditions. As well as multi-point focusing, the GF3 also provides single, pinpoint, tracking, and face detection autofocus modes. In single-point mode, the focus point can be placed anywhere within the image frame, by simply dragging it on the touch-panel display. Autofocus speed is said to be similar to that of the Lumix G3 and GH2 models, and our test results agree.
Of course, you can also focus manually, and the GF3 offers a manual focus assist zoom that enlarges the display around the focus point, allowing precise focus tuning. Three zoom levels are available -- either 4x, 5x, or 10x. As in the G3, the lowest zoom level shows an enlargement only at the center of the screen, overlaid on the full image, providing a reasonably intuitive way to focus while retaining your desired framing.
Exposure. The Lumix GF3 offers still image shutter speeds ranging from 1/4,000 to 60 seconds. Images are metered with the Live MOS image sensor, using a 144-segment multi-pattern metering system, and the GF3 also provides both center-weighted and spot metering modes. +/-3.0 EV of exposure compensation is available, set in 1/3 EV steps, and the metering system has a working range of EV 0-18 (with an f/2.0 lens at ISO 100 equivalent.)
This change makes the built-in flash doubly important, and unfortunately, it still has a rather modest guide number of just 6.3 meters at ISO 160 equivalent. With that said, being a relatively compact camera, it's likely that an external flash would get left at home anyway, so perhaps the lack of external flash connectivity won't prove much of an issue.
Creative controls. As in the G3, Panasonic has retained its two main creative control function groups from the earlier GF2 model in the GF3, but with new names for each.
The earlier My Color mode is now known as Creative Control, and provides access to six effects, one more than in the G3 but two less than the GF2. Choices are Expressive (pop-art style), Retro (soft, tarnished effect), High Key (brighter image), Sepia, High Dynamic (localized color and contrast enhancement), and Miniature Effect (linear graduated blur towards the edges of the image).
The Film Mode function has also been renamed to Photo Style. This offers a selection of six presets, plus a custom mode, each of which can be tweaked in terms of contrast, sharpness, saturation (except in Monochrome mode, where it is replaced with a color tone adjustment), and noise reduction. Presets include Standard, Vivid, Natural, Monochrome, Scenery, and Portrait.
There are also 17 Scene modes that help amateurs get the results they're looking for without the need to understand shutter speeds, apertures, and the like, as well as Intelligent Auto and Intelligent Auto+ modes that both offer maximum ease of use, but differ in their level of control over the look of images.
The differences are threefold. Panasonic has dropped the 13Mbps "FH" and "F" options for AVCHD format, dropped the non-standard 848 x 480 pixel WVGA video capture mode, and replaced the GF2's stereo internal microphone with a monaural mic.
Exposure during video recording is fully automatic, though aperture can be adjusted while recording using the Defocus Control slider in either Intelligent Auto mode, and a flicker reduction feature lets you force the shutter speed to 1/50, 1/60, 1/100, or 1/120 second. Exposure compensation and white balance can be adjusted before recording starts in Intelligent Auto+ mode. Creative Control effects, Photo Styles, and 11 scene modes are also available for videos.
Of course, continuous autofocus is available during movies, complete with Touch AF. Other video recording features include a wind cut filter with four settings, and the mic's sensitivity can be adjusted to four levels. See the Motion Picture menu animation above right for additional features and settings.
The GF3 also includes a proprietary connector that provides for both USB 2.0 High Speed data transfer, and standard definition NTSC composite video output with monaural audio output. The USB port has PTP (for PictBridge compatible printers) and Mass Storage modes.
Storage. The Panasonic GF3 stores its data on Secure Digital cards, including the latest generation SDHC and SDXC types. As well as storing still images in JPEG compressed format, the G3 can also write RAW files, either alone or alongside a JPEG copy of each image. When using Panasonic's unusual 3D lens, the GF3 saves images in MPO (Multi Picture Object) format, with each MPO file containing two JPEG images with differing perspective. As noted previously, movies can be stored with either AVCHD or Motion JPEG compression, depending on the resolution.
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