From megapixels to viewfinders to sensors, size matters.
Imaging: 24.6MP, effective, fullframe CMOS sensor captures images at 6048x4032 pixels with 14 bits/colorin RAW mode.
Storage: Dual slots: CompactFlash Type I/II, including UDMA and microdrives; Memory Stick PRO Duo. Stores JPEG, RAW, RAW + JPEG.
Burst rate: Full-sized JPEGs (Extrafine mode), up to 11 shots at 5 fps; RAW,up to 12 shots at 5 fps.
AF system: TTL phase detection with 9 illuminated selectable focus points and 10 nonselectable assist points. Single-shot and continuous AF. Tested sensitivity down to EV -2 (at ISO 100, f/1.4).
Shutter speeds: 1/8000 to 30 sec plus B (1/3-EV increments).100,000-cycle rating.
Metering: TTL metering with 40-zone evaluative, centerweighted, and spotmetering (percentage of viewfinder not disclosed).EV 0-20 (at ISO 100).
ISO range: ISO 100-6400 (in 1/3-EV increments).
Flash: Supports ADI and TTL autoflash with Alpha flashes; X-sync at 1/250 sec, at 1/200 sec with Super SteadyShot Inside engaged.
Viewfinder: Fixed eye-level pentaprism.
LCD: 3-in. TFT with 921,600-dot resolution.
Output: Hi-Speed USB 2.0, HDMI (mini-type) video, 3-pin remote. PictBridge and PIM III compatible.
Battery: Rechargeable NP-FM500H Li-ion, CIPA rating, 1,000 shots.
Size/weight: 6.3 x 3.3 x 4.6 in., 2.14 lb with card and battery.
Street price: $3,000, body only.
Accuracy: 100% (Excellent)
Magnification: 0.74X (Very Good)
• Nikon D700 ($2,700, street, body only; $3,375 with 24- 120mm f/3.5-5.6G ED -IF AF-S VR lens) While the Nikon doesn't match the A900's resolution, it has the edge in color accuracy and focuses faster in extremely low light. Its biggest edge is in noise -- or, more important, lack of it. The D700 reaches 2 full stops further in sensitivity than the A900, with a top ISO of 25,600; at ISO 6400, it produces noise equal to the Sony's at ISO 1600. So lowlight shooters should look to Nikon. In most other ways, the two cameras are on par, although Nikon's 3D Matrix Metering beats Sony's Multisegment for those shooters who don't use spot- or centerweighted metering. A major advantage of the A900: in-body image stabilization. Nikon makes you buy stabilizedlenses to combat shake.
• Canon EOS 5D Mark II ($2,700, street, body only; $3,500 with 24- 105mm f/4L EF IS lens) Canon keeps the resolution war alive with its new 21.1MP DSLR. But the big story is the Canon's 1080p HD movie mode, which neither the Sony nor the Nikon D700 offers. Canon also keeps up with Nikon by providing a top ISO of 25,600, as well as more versatility in brighter light, with a low of ISO 50. Both the A900 and D700 bottom out at ISO 100. This Canon lags slightly with its 3.9 frame-persecond burst rate, compared with 5 fps on both the Sony and the Nikon. We haven't yet tested the 5D Mark II, but we're eager to see how it doesin the Pop Photo Lab.