Anyone interested in looking at boring ISO crops? well, there's a lot
of chatter in various Sony forums about the ISO performance of the new A580, so I thought I'd provide some side-by-side ISO
comparisons of Sony's flagship A900, the old and outdated A700, and last, but not least A580. The A580 received rave
reviews about its high ISO performance when it was introduced, so how does it stack up to the older Sony cameras from the
last decade? Read on to find out!
There are three sets of ISO comps below. The top set
shows ISO center crops from the A580 and A700, with the current Ver. 4 firmware. The second set has the same A580 crops
on the left, but with the A900 crops now in the right column. The last set has the A700 with Ver. 3 on the left, and
the most current Ver. 4 on the right (as of this review, 2/11).
All three cameras have different megapixel
sensors, so that's why the crops don't cover the same area. I didn't try to resize the image area in each crop because
I wanted you to see the resolution differences also. All images were shot in RAW at an aperture of F/8, white balance
set to 2900k and trimmed to magenta 3. A tripod was used, with the two second timer, and focusing was done manually.
The CZ 24-70mm F/2.8 was used at 24mm for the A900, and the Sigma 10-20mm F/4-5.6 for the A700 and A580, set to 16mm.
Images were prepared using Adobe camera raw 6.3, there were no image
adjustments made of any kind, except cropping and converting to Jpeg for the site. Crops are from the dead center of
the image.
The higher resolution of the A580 in noticeable here, but the noise pattern is very similar until you
creep up around ISO 3200, where the A700 starts going bad, and ISO 6400 is obviously far better on the A580.
Here the A900 shows the quality of its 24mp full frame sensor, with higher resolution clearly visible
from ISO 200-1600 to almost 3200. However, the A580 starts to really shine at very high sensitivities, and appears to
out-resolve the A900 at ISO 6400, while holding better color, that's somewhat surprising, but shows how noise reduction and
sensor technology have progressed in two plus years since the A900 was introduced. A few people claim Sony added better
noise reduction to the A900 with the new firmware update. Consequently, I updated the A900 to ver. 2.00, and noticed
no difference at all. Sony says there was no modification to noise reduction in this firmware (Ver. 2.00) and I can
confirm that.
The only noticeable thing here is the smearing luminance noise reduction in the Ver. 3 firmware (left
crops), fortunately the new Ver. 4 update eliminated that, and makes the noise pattern look more like the newer Sony cameras.
In reality, it doesn't offer any improvements in my opinion.
That's it, go back home.
