Sony A77 Review: Disappointing A77 Sensor

Started Aug 26, 2011 | Discussions thread
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Sony A77 Review: Disappointing A77 Sensor
Aug 26, 2011

Sony A77 Review: Disappointing A77 Sensor

I have been a Minolta/Sony supporter for 40 years and have awaited the A77 for a long time, as all alpha fans have.

I was delighted with the initial announcement of the A77 yesterday (8/24/2011). The camera had absolutely everything that I wanted for the A700 replacement. I sought out internet sights where they had test photos as well as incidental photo images made with the A77 so I could close inspect the images. I became quite upset with the extreme loss of detail, mildly observed first at iso 100 and then becoming intense even at iso 800.

I have included some side by side photos which are labeled as to which camera and iso setting are represented. Look at these photos below and see what I am disturbed about and see if you agree? There is no processing or resizing of any kind.

The first photo is a side by side of the iso 100 and iso 800 images from the A77.

The second is a side by side of the A77 at iso 800 and the Nikon D3x at iso 800.

These photos are jpeg types but looking at the raw images shows the same loss of detail.

Why these two comparisons. Well the first shows the extreme loss of fine detail when changing from iso 100 to iso 800 in the A77. The second shows the preservation of that detail at iso 800 in the Nikon D3X. However, I could have used almost any other APC or FF sensor camera as none loose detail like the A77. Granted the A77 is not an $8,000 camera but then again neither is the 21 MP Canon Eos 5D Mk II or the 16MP Pentax K5 in comparison to the 24MP, $1400 Sony a77.

We all want low noise. But here the algorhythms used by Sony are smashing and smearing fine detail and redrawing lines so that resolution figures and noise figures look OK but detail is destroyed. Perhaps that detail is what some call the IQ of a sensor. Those algorhythms makes the test results for resolution figures, as published by our testing institutions, look fair as well as make noise figures look good. But that does not tell the tale about preservation of fine detail - which is what resolution figures are supposed to be about in the first place. There is no test for that – only direct view in side by side images. What gain is there in lowering noise but destroying detail? We could as well do that in Photoshop or many other programs and do a better job, and all the while permitting us to dial in the amount of noise reduction we might want as well as have the option of no noise reduction. Here detail is lost and not recoverable even at iso 100 and easily seen at iso 200 and above as in this site’s published sample photos.

Why go to a 24 MP sensor in the first place - unless you want detail in your photos so you can make enlargements (not the major reason) or crop to a high degree and still get a retina sharp 8 x 10 print (major reason).

I first noticed the problem when looking at sample photos from this site “DPREVIEW” for the A77. Most are shot at iso 200 but looking at those at full size shows all kinds of distressing aberrations resulting from overprocessing of the noise.

I am not a physicist but I believe the problem is how small they have made the pixel sites to cram 24 million of them into a half sized sensor (re: 36 by 24mm as full size). The laws of physics reveal that light can only be focused and magnified so many times. That is why electron microscopes can achieve magnification ratios of 100,000 times and light microscopes only come in at 1,000 times. The images from this A77 sensor look reminiscent of those from small sensors in point and shoot cameras – and likely for the same reason. Those have the smearing and texture changes and distortions and straight lines looking like they were drawn by hand and with detail pinched off. This mirage like effect and redrawing efforts, maintain good test results but are destructive of image quality. This is very different that the usual loss of detail that occurs with the types of processing used in other APS or FF sensors to date. Those usually look like an out of focus image but are not smeared and distorted as with the A77.

I personally believe that within the current limits of the best glass to resolve fine detail and have fairly low noise on images, the best pixel density ratios are those of the A900 and D3X. Those are 24 MP but in a 36 by 24 mm sensor not an APS size. 24 MP in an APS yields pixels that are just too small and noise processing has to cut too much detail.

So I was ready to run out and buy the A77 yesterday. Now all I can do is wait for a FF sensor and hope it is not 48 MP sized as that leads to pixels that are just too tiny.

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