tldr; 2008 flagship full-frame A-mount. 24.6MP, huge OVF, pro build. Sony's first FF DSLR. Historical significance.
$11.99 on AmazonScores based on sentiment analysis of topic-related comments
Best praise vs top criticism for Sony Alpha a900
“Omg finally someone with an a900, my white whale. How is this camera doing for you? I’ve been looking for one for ages.”
“There is 1-1.5 stops of difference. That is, not only in "crop factor" but in everything -- in noise performance, DOF, DR, the lot. This is not the complete truth though, as generational differences will be more important -- my a6600 absolutely smokes my a900 in noise performance, for example. But generally for the same amount of pixels in FF/APS sensors of the same generation, the difference will be 1-1.5 stops. Now it can be argued that this isn't much, that this is uninteresting provided light is good, and that slightly better DOF is a pro. But there is a difference, and minute differences can certainly trigger purchase impulses. ;-) Also, 35mm in film didn't win the format wars because it was "the best", but because it was a reasonable compromise; good quality in a very portable (even pocketable) package. A smaller sensor can mean a smaller camera, but "too small" is a thing (I have 3D printed an extension to the grip of my a6600), and diffraction will get you if the sensor gets too small as the 4/3 systems have belatedly discovered. Lastly, innovations have arrived at the FF cameras first, just watch how long it took IBIS to arrive in the Sony APS-C models! It was the a6500, even though the full-frame a7ii had it two years before, the APS line was leading the FF line by several years, and almost all Sony APS SLRs had it.”
9 Reddit opinions analyzed • Last updated 4/4/2026