When I post flat-as-Kansas corrected SNR vs ISO curves like I did yesterday, I often get emails saying, “That can’t be right. Show me some pictures.” I always oblige. I put a Zeiss 35m mf/2 Biogon ZM on the Sony a7S, using a Novoflex adapter. I put the camera on a big RRS carbon fiber… [Read More]

Measuring read noise is fine, but by the time you can see the read noise, the photon noise is usually pretty bad. In fact, for me, the photon noise is more important as a measure of practical image quality. Here’s a test that shows the combined effects of photon and read noise as a function of… [Read More]

I need a break from the lens cap pictures. Let’s see how legacy glass does on the a7S. The Zeiss 35mm Biogon in the Leica M-series mount is a delightful little lens. Small, and with nice controls, it seems like it was made for cameras like the alpha 7 series. However, it is the toughest… [Read More]

There’s a way to look at read noise vs ISO setting that’s different than the curves I presented in yesterday’s post. It’s a bit less intuitive, but, if you can get your head around it, it can give useful insight into how the sensor works. Rather than presenting the standard deviation of the noise in the raw… [Read More]