The Sony
A850 and
A900
are full frame cameras that pack in 24.6-megapixels on that big
sensor. The cameras appear at the top-end of the Alpha system line up.
At first blush, the A850 appears almost identical to the pricier Sony
A900. After delving deeper into the A850, you’ll discover that there’s
really not a whole lot of difference between it and the A900.
Because of the similarities between these two cameras and the fact
that I reviewed them simultaneous, I decided to publish one review for
both cameras rather than than two separate reviews with only minor
changes in the text.
Sony A850 and A900 Key Differences
The differences between the A850 and A900 are so minor that it seems
hard to justify the purchase of an A900 over the A850, given the $700
price discrepancy. The A850′s frame rate covers 3 fps, compared to 5
fps on the A900. Additionally, the A850 viewfinder coverage is 98% of
the frame, compared to 100% coverage from the A900. Finally, the A900
includes a wireless remote, which is an excellent option; however, those
who opt for the A850 can take some of that $700 they save to purchase
the
same remote for $30.
Auto-focus
The A850 and A900 have a great auto-focus system inside. You get 9 AF
points, which can be selected by the user. The center AF point is
center dual cross type for extra sensitivity. There are also 10 assist
AF points.
The focus speed is quick and accurate on both cameras – even in low
light. If you’ve read Photography Bay for a while, then you know that I
like to use a single focus point, selecting individual points as
necessary depending on the composition. Adjusting focus points is
straightforward and easy with the joystick. As noted earlier though, if
you like to change focus areas (
e.g., Wide AF area, Spot AF area, etc.), then you’ll have to jump back to the quick menu.
My main gripe with the AF system is frame coverage. Nothing in this
class of cameras stacks up to the frame coverage on the Nikon D700.
While I’ll equate the speed of the AF system of the Sony cameras to the
D700, the frame coverage and focus point options just don’t stack up for
the A850 and A900. As a result, I end up with a lot of “focus and
recompose” shooting.
Image Quality
With 24.6-megapixel, the A850 and A900 deliver in the resolution
department. Files from the Alpha cameras are 6048 x 4032 pixels in
size. With resolution like that, you can take advantage of the cropping
space.
The color reproduction is solid straight out of the camera. I really like the results from the A850 and A900 – in good light.
In lower light, if you bump the ISO speed, then you can get in
trouble pretty quick. The 5D Mark II and D700 easily have a stop or two
advantage over the A900 and A850. Shooting over ISO 1600 would be
ill-advised for the Sony DSLRs.
Previously, I published an ISO comparison for the A850 and A900,
along with the 5D Mark II and 7D. Below is a short sample taken from a
100% crop of the test scene.