Archives for August 2015

From the mailbag: My question is: the new Sony seems to be the ideal camera for my work as a movie unit stills photographer. It is silent and full frame which are two of my main concerns. However, I’m concerned about low light shooting. Will this camera give acceptable images for reproduction at high ISO?… [Read More]

The mechanical shutter on the Sony a7RII is supposed to be better damped. It also has electronic first-curtain shutter (EFCS). How do those things make moderate telephoto pictures sharper? The protocol: The cameras: the Sony a7RII and Sony a7R. The lens: the Leica 180mm f/3.4 Apo-Telyt-R The filter: Heliopan 77mm variable neutral density. The lighting: a… [Read More]

I was asked if the spatial filtering mentioned in the previous post that takes place in bulb mode at ISO 6400 also happens at other ISOs. I tested three of them. It looks like the filtering is nonlinear, since it has different effects at the different read noise levels of different ISOs. I assume, but… [Read More]

The other alpha 7 cameras switch from 13-bit to 12-bit precision when the shutter is set to bulb, even if the shutter mode is single shot. Is that the case with the a7RII? Yes, indeed. Here’s the histogram of a 6-second single shot, ISO 6400, dark-field exposure made using the camera’s shutter timing mechanism: Every… [Read More]

Earlier, we saw indications that the Sony a7RII was doing spatial filtering of raw images at ISO 32000 and above. In such situations, I find it instructive to look at spatial frequency graphs. Assuming that some of you do as well, here is a graph of the horizontal and vertical spectra of a 1000×1000 pixel… [Read More]