Saturday, January 30, 2010

Sony Alpha A900





Sony Alpha DSLR-A900 Digital SLR Camera


The Sony Alpha DSLR-A900 is a powerful digital SLR camera aimed squarely at professionals and enthusiasts who covet a full-frame sensor--and who can afford the investment. This camera costs $3000 for the body only, and $5250 with a 24mm-to-70mm f/2.8 lens and the HVL-F58am flash (prices as of 12/10/08).

This model packs a whopping 24.6-megapixel, full-frame CMOS sensor. "Full-frame" means the sensor's size is the same as a 35mm film frame; this is a boon for landscape shooters, who want to achieve wide angles using lenses that were originally designed for 35mm SLRs. With a full-frame digital sensor, head-scratchers such as focal length multiplication, field of view, and crop factor are eliminated because the sensor size matches the circle of light that the lens casts, thus picking up all the detail that the lens has to offer. A larger sensor will also offer a greater range in depth of field.

The A900's potential for producing a high degree of detail created buzz in the photo community--for good reason. What about the noise that usually accompanies such high pixel density? Is it worth trading in your kit if you've been loyal to another brand?

The answer is "maybe." Former Minolta users can pair their lenses with the A900. However, the noise issues introduced by a chip as pixel-dense as the A900's somewhat mitigate the benefits of a higher resolution.

The A900 looks and feels like a serious camera to be reckoned with, and it is. With a body built entirely of magnesium alloy, this battleship is also environmentally sealed. It has a 3-inch, 922,000-pixel TFT screen that's sharp and bright, and can only be called awesome.

The camera's well-articulated menus are reasonably intuitive to navigate, and in keeping with the style found on other Sony DSLRs. Included are a number of dedicated menu buttons, as well. The A900's viewfinder was wonderful to shoot with; I found that it provided a 100 percent field of view. The large pentaprism behind that adds a little bulk, but the camera is still comparable in size and weight to the Sony Alpha DSLR-A700 and to higher-end Canons and Nikons. I used the Sony 24mm-to-70mm f/2.8 lens, with glass by Zeiss. The camera's built-in, in-body image stabilization helped quite a bit while I was shooting handheld.

The A900 has some great features, including dual processors to handle all that megapixel data (and the camera is fast and responsive), a small LCD on top that displays very basic information, additional noise-reduction modes, and an expanded array of dynamic range options.

Scene modes are accessible through the menu and are easy to find, although the process is admittedly less simple than selecting them on a dial, as you could do on the A700. Three custom modes have replaced the scene modes on the dial (as on the A700); some photographers might prefer this new option, as it is quick, convenient, and personalized.

The camera has incorporated something that Sony calls Intelligent Preview. It isn't the same as live view, though, and in my opinion it isn't all that useful given the extra time it takes, considering all the post-processing that high-level photographers generally will do later on a computer (especially if you are shooting RAW).

The A900 takes a preview shot, shows it to you on the TFT screen, and allows you to apply various settings to it, such as white-balance or exposure adjustments. You then take the "real" shot (where your subjects would still be in the same place), and the A900 applies your chosen settings to the photo. The A900's expanded dynamic range options are extensive; they mainly added shadow detail to my images, and didn't really affect the highlights. Generally, I found that the camera had a very respectable dynamic range even without my using the setting. If you're in a tough spot with a lot of contrast, however, the dynamic-range options can help brighten up the dark areas of a photo, quite dramatically.

Overall the A900 outperformed the other two Sony models--the A700 and the A300K--we've evaluated in the PC World Test Center's digital camera tests. This model earned an image-quality score of Very Good, as its predecessors did, but it was at the high end of the spectrum and ranked seventh overall.

My pictures in the field shot at ISOs below 800 looked great and sharp, and had minimal noise. But when I switched to photographing indoors and on my street corner, I cranked it up to ISOs 1600 through 6400--and I saw a lot of chromatic noise in my field shots.

I saw the chromatic noise when I shot in both RAW and JPEG. The A900 does offer the option of turning noise reduction off when shooting RAW, but even with post-processing most of the results were not viable--shooting with high-speed film would have been preferable. When shooting JPEGs, the A900 always applies some degree of noise reduction, softening noise at high sensitivities but producing an unfortunate smeary look. Luckily, you can dial the noise-reduction settings up and down using the camera's many levels of noise control.

The A900 has no built-in flash (as the A700 does). You''ll need to add one for indoor flash shooting (Sony sent us the $500 HVL-F58am for use in our review). Part of the package, though, is a remote control, a fairly unusual extra. Another option is a vertical grip that has capacity for two more batteries and adds more buttons to the equation, offering control over function, focus, metering options, and AE compensation settings.

Overall I enjoyed using the Sony Alpha DSLR-A900, and for the most part I was very happy with its image quality. A full-frame 35mm sensor is indeed exciting, but I'm not convinced of this model's value. It may be a good value to you, if you crave the wide-angle capabilities that full-frame offers. Nevertheless, I've seen equal or superior results from 12-megapixel DSLRs, for less dough.

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