Sony A900: A Closer Look at 24.6MP Resolution and Noise
by Wesley Fink on October 27, 2008 2:00 AM EST- Posted in
- Digital Camera
Looking Forward
The Sony A900 is a truly revolutionary camera. As the highest resolution full-frame DSLR you can currently buy it distinguishes itself with astonishing resolution. As discussed in our preview it is also the first full-frame with body-integrated Image Stabilization (add 2 to 4 stops to hand held shooting) and the viewfinder is the best, brightest, sharpest that we have ever seen in a DSLR - or perhaps in any camera.
It is important to keep those huge pluses in perspective because image noise at extended ISOs, while just one factor in the total image quality equation, is definitely not a strength of the A900. Compared to the Nikon D700, noise in the A900 is about two stops worse. That means the D700 at ISO 6400 exhibits about the same noise as the A900 at ISO 1600. In the case of the D700 that applies to both the actual pixel comparisons as well as the double pixel samples downsized to reflect the same image view in both crops. Despite the huge noise advantage, the D700 outputs nothing near the resolution and detail of the A900, which should not come as a surprise.
The Canon 5D is now three years old, but noise control is still about a stop or two better than the A900. However, we noticed for the first time how much Canon softens images at higher ISOs in an effort to control noise. Looking at the pixel level, high ISO Canon images are extremely soft at higher ISO settings, though they are quite sharp in the lower ISOs most sites use in evaluating the 5D output. Taken in total the A900 is again a clear leader in detail compared to the 5D. The 5D has perhaps a one stop advantage in noise when the A900 and 5D are equalized for sharpness.
Finally we come to the biggest surprise of all, which is our comparison of the A900 noise to the APS-C sensor in the A700. This is the same sensor used in the Nikon D300 and the most recent Nikon D90. When the A700 was first released, some in the press trashed it because of its heavy-handed noise reduction techniques. Sony has worked hard to answer those complaints, and most users were pleased with the v3 firmware fixes. With the release of the A900 Sony also released a v4 firmware for the A700, which allows complete disabling of NR plus a range of adjustments in noise reduction. V4 incorporates in the A700 all Sony had learned in developing the A900.
With sensor density of the A900 less than the A900 (2.9 vs. 3.3) we really thought the A900 would shine compared to the A700. In fact the A700 is about two stops better in noise control looking at actual pixel crops and one to two stops better looking at crops equalized for image view (A900 down-sampled to equivalent 12MP). This performance difference is a complete surprise and it is either good news or bad news depending on your perspective. The bad news version is that the A900 sensor is inherently a high-noise sensor and the high ISO noise performance is as good as we will see. The good news version is that the A900 was just released and, like the A700, Sony will continue to improve the noise performance in future firmware/software releases. We certainly saw that in the A700, but we did have the Nikon D300 as the constant reminder of what that sensor was capable of.
Our hands-on test of the A900 reveals a mixed bag of performance. At Lower ISOs, 100-400, nothing on the market comes close to the Sony. A little is given up at 800-1600 and if that were as bad as it got the A900 would be something of a Holy Grail. However, noise at ISO 3200 and 6400 are truly not competitive. High detail is still there but it is seriously marred by high noise. In the end our expectation is that professionals will stick to ISO 100-400 for the highest resolution shots you can get from a camera in this class. Action shooters and the rest of us will also be happy with ISO 800 and 1600. However, dial in above ISO 1600 only if you will be happy with stunning detail in smaller prints.
The last page contains a few sample images taken in the couple of weeks the Sony A900 has been in the office. As always, we chose the images to show both the strengths and weaknesses of the camera we are testing. The A900 is capable of capturing amazing detail and if you do a lot of pixel-peeping on these images you will see exactly what we mean. There are also a couple of shots that show the potential impact of poor noise performance at higher ISO, which is not always as bad as it sounds.
The Sony A900 will likely be long remembered for its record-setting resolution and its utility as a camera that is a true working tool instead of an amalgam of gadgets. The stunning 100% viewfinder is one example of that, but so is the logical and simple control that is a part of every aspect of the A900. It is not without its flaws but in total the A900 is definitely greater than the sum of its parts or any one area of measured performance.
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CEO Ballmer - Monday, October 27, 2008 - link
These things are very nice, but the ZuneCam will prove they are waaaaay over-priced!http://fakesteveballmer.blogspot.com">http://fakesteveballmer.blogspot.com
strikeback03 - Monday, October 27, 2008 - link
I'm guessing default settings in JPEG. Which is a valid baseline, but given different manufacturers different philosophies on JPEG processing, makes commenting on apparent sharpness of the image somewhat difficult. Also, was any form of dynamic range expansion turned on? I'm surprised at how much color noise is already appearing in the A900 shots at ISO 400, wonder if it is a result of boosting some shadows?As you guys are buying your test bodies, I can understand not having a 1DIII, but making statements such as "At Lower ISOs, 100-400, nothing on the market comes close to the Sony." seems a bit odd without at least trying it against a body with 86% of the pixel count. And obviously if those in the market have the means to get a medium-format back and associated gear, you are far beyond the capabilities of the A900.
Wesley Fink - Monday, October 27, 2008 - link
Yes, default settings were used in all parameters, including dynamic range expansion. We tried to be careful to say compared to others in its class, which is obviously full-frame 35mm-size sensors. We have not compared any of the full-frame cameras to medium forma or anything like the new Leica medium format that uses the Kodak sensor, nor do we plan to.As for comparisons to the 1Ds Mark III, the comments were based on conversations we had with Pros who have shot both the Sony A900 and the Canon 1Ds III. We also looked at images shared with us by a couple of them. We would be more comfortable with our own hands-on with the $8000 1Ds III but that will be a moot point once we have the 5D Mark II. Canon claims the 5D II sensor, with the same resolution, is superior to the 1Ds III so we will soon get our first hand look.
melgross - Monday, October 27, 2008 - link
Some odd conclusions both here and DPR.One thing that stands out here though, is the strange notion that with all the noise, the higher resolution is of any use.
I don't know of anyone who wouldn't control noise with noise reduction once it reaches the levels of the a900 at ISO 800. Even 400 isn't great, just ok.
Once that is done, the higher resolution will be no better than anywhere else. The more noise, the more noise reduction, the less detail.
It would have been more interesting if noise reduction was applied to see the effects of bringing it in line with the other cameras. Where would the detail have gone?
In addition, if noise is so high at higher ISO's, as it is, making smaller prints so as to not see it, would also mean making smaller prints than would allow you to see the higher resolution as well. No gain, no pain.
I also find it interesting that field reports about this camera from both DPR and the Luminous Landscape have agreed that real-world pictures show less detail that the Canon 1Ds mkIII. The high detail is smeared because of the non removable noise reduction done before the A/D converter (as opposed to the noise reduction that can be turned off after the A/D converter.
The subject used for the comparisons is also pretty bad. I'm sure something more suitable that that could be found.
JarredWalton - Monday, October 27, 2008 - link
I shoot plenty of objects at ISO 100-400, sometimes using a tripod. In such cases, the differences between 12MP and 26MP will definitely be apparent. That said, I don't do print work and will just end up cropping and resizing down to a manageable resolution. Still, for details of a motherboard as an example, that increased resolution could be very handy.As for the subject matter of the ISO comparisons, I'm of the opinion that as long as it's static (i.e. the same in each review) it serves its purpose. We've all seen the various chart photographs (which are widely available elsewhere), but I suppose Wes can reproduce those if necessary. I just don't see how it makes much of a difference one way or the other; the sample images at the end do a good job of showing other possibilities with the camera, and personally I think some of the images look very nice indeed. Just stay away from ISO 800 or higher if possible.
strikeback03 - Monday, October 27, 2008 - link
My complaint with the ISO image subject is a lack of anything to help differentiate between good NR software and a low-noise sensor. With a test image composed almost entirely of smooth single-color areas, good NR software could make those pretty smooth while maintaining the borders between colors. A subject with more detail makes it harder to just blur noise away without seeing the results in detail captured.haplo602 - Monday, October 27, 2008 - link
and on a color checker chart you can evaluate sensor performance in high ISO for colo/saturation drifts ... this cannot be seen on the current simple 3 color test target ...LTG - Monday, October 27, 2008 - link
This review kept reminding me of the DPReview.com review of the same camera.It's definitely different works, but the emphasized points are very similar like choosing to commend sony for lack of gadgetry.
I guess that fine we all build thoughts from some starting point - but I'll eat my left shoe if the author didn't read the dpreview article before writing this.
yyrkoon - Monday, October 27, 2008 - link
You know, you could have just as easily not left a comment at all.No one really cares what your thoughts are on web plagiarism . . .
Wesley Fink - Monday, October 27, 2008 - link
Plese read my Sony A900 Preview where I praise the same points long before dpreview published their review of the Sony A900. We all read other reviews but I have no problem reaching my own conclusions.