Tuesday, October 21, 2008
Choose your ideal camera for photographing birds and other wildlife
The Samsung GX-20 is essentially the same camera as the Pentax K20D, so it can be expected to perform similarly for wildlife photography. Samsung manufactures the 14.6-megapixel CMOS sensor used in both cameras, which was developed by Samsung and Pentax.
Major differences are cosmetic (shapes of buttons, menu layout and the like), and the fact that the K20D gives you a choice of two RAW formats, Pentax’s own PEF and Adobe’s DNG, while the GX-20 provides only DNG (plus JPEG, of course). As on the K20D, a handy RAW button lets you quickly switch from JPEG to RAW recording.
Useful wildlife features include quick autofocus that can handle birds in flight, sensor-shift Optical Image Stabilization that works with all lenses, a sensor-dust remover, excellent weather resistance and dustproofing, thanks to 72 seals, and a 1.5x focal-length factor that effectively increases the focal length of any lens by 50% over its length on a 35mm camera.
Like the K20D, the GX-20 can use virtually all Pentax lenses. Samsung also offers its own lenses and Schneider lenses developed specifically for the camera. As with the K20D, the best wildlife lenses are the Pentax DA* 200mm ƒ/2.8 and 300mm ƒ/4 SDM, and the Sigma 300mm ƒ/2.8, 500mm ƒ/4.5 and 800mm ƒ/5.6 super-telephotos in Pentax mounts.
While it’s not the quickest D-SLR (others are better choices if your wildlife specialty is fleeting bird-in-flight moments), the SD14’s unique Foveon X3 full-color-capture image sensor, 1.7x focal-length factor, excellent lens selection and surprisingly low price make it a fine camera for less-frenetic wildlife subjects.
Conventional Bayer-array image sensors record just one primary color at each pixel site, then re-create the missing colors by interpolating data from adjacent pixels using complex algorithms. An image-softening, anti-aliasing, low-pass filter is needed over the sensor to minimize color artifacts and moiré patterns. The Foveon X3 sensor takes advantage of the fact that different light wavelengths penetrate silicon to different levels, in effect, stacking three layers of pixels. The top layer records blue, the middle layer green, and the bottom layer red, much as color film works. Thus, the X3 sensor records all three primary colors at every pixel site. There’s no need for the Bayer colored-filter array over the pixels, interpolation and image-softening, and anti-aliasing filter required by conventional sensors. The result is the potential for sharper, more accurate RAW images.
Aside from its unique image sensor, the SD14 offers a solid, no-nonsense camera that’s easy to use. It offers a quick mirror-lockup function (handy for high-magnification photography) and a sensor-dust protector that can be removed readily for infrared photography.
Sigma offers more than 40 lenses for the SD14, including a 4.5mm circular fisheye. The best for wildlife include the 300mm ƒ/2.8, 500mm ƒ/4.5 and 800mm ƒ/5.6 EX pro prime lenses and the 120-300mm ƒ/2.8, 300-800mm ƒ/5.6 and 200-500mm ƒ/2.8 zooms. The 200-500mm’s ƒ/2.8 aperture makes it the fastest 500mm lens on the market, and it comes with a 2x converter that turns it into a 400-1000mm ƒ/5.6. Sigma also offers more cost-friendly 120-400mm and 150-500mm OS zooms, plus 1.4x and 2x converters for its tele lenses.
Predecessors: SD10, SD9
Cool Factor: Unique Foveon X3 full-color-capture image sensor
Sensor: 4.7x3-megapixel Foveon X3, 1.7x
Stabilization: OS lenses
Max. Shooting Rate: 3 fps
ISO Range: 100-1600
Longest Current Lens: 800mm
Estimated Street Price: $800
With 24.6 megapixels on a full-frame sensor, the A900 has enough resolution to let you crop down to APS-C format (1.5x focal-length factor) and still have 10-megapixel images. We haven’t had a chance to test this new model (samples weren’t available at press time), but a 24-megapixel, full-frame D-SLR for $3,000 sounds promising. Highlights include that new Sony 24.6-megapixel CMOS sensor, dual Bionz image processors, 5 fps shooting, a 3.0-inch, 921,000-pixel LCD monitor, intelligent preview function and ISOs from 200-3200 (expandable to 100 and 6400)—all in a body weighing about 30 ounces.
Sony’s DRO (Dynamic Range Optimizer) in the A700 model we tested was effective in retaining highlight and shadow detail in harsh sunlit scenes; presumably the feature will do likewise for the A900. While we haven’t had a chance to try any Sony D-SLR with a really long lens, autofocus performance was very good with shorter focal lengths. The A900 features a new 9-point AF system with 10 assist points and a center dual-cross-type sensor for added performance with lenses of ƒ/2.8 or faster. The Super SteadyShot sensor-shift image stabilization in our A700 test camera proved effective; the A900 will be the first full-frame D-SLR to offer this feature. All Sony D-SLRs have built-in sensor-dust removers; it will be interesting to see how effective it will be with the big full-frame sensor.
Sony D-SLRs accept Sony and legacy Minolta Maxxum lenses, plus Zeiss T* lenses designed for the cameras. The best wildlife lenses include the Sony 300mm ƒ/2.8, 500mm ƒ/8 mirror and 70-300mm ƒ/4.5-5.6. Sigma offers 500mm ƒ/4.5 and 800mm ƒ/5.6 super-teles in Sony mount, and Tamron offers a 200-500mm ƒ/5-6.3. All three offer 1.4x and 2x teleconverters.
Predecessors: DSLR-A700, DSLR-A100
Cool Factor: 24 megapixels for $3,000
Sensor: 24.6-megapixel CMOS, 1.5x
Max. Shooting Rate: 5 fps
Anti-Dust: High-frequency vibrations
ISO Range: 100-6400
Longest Current Lens: 800mm
Estimated Street Price: $3,000
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