Archives for August 2015

There have been reports of strong self-heating effects at long exposures with the Sony alpha 7R Mark II (a7RII). I mentally discounted them, because I didn’t know of a mechanism that would preferentially heat the sensor with the shutter open and the photodiodes sitting there back-biased and waiting to snag a passing photon. But the… [Read More]

A participant in the DPR Photographic Science and Technology forum challenged my — admittedly based on gut feel and experience — contention that, for critical focusing, it was more accurate to do it manually than with autofocus. I thought about it, and decided that I wanted to see some real data. I took a Sony… [Read More]

A few days ago, I determined that shutter speeds over 1/1000 second using electronic first curtain shutter (EFCS) on the Sony a7RII with a Zeiss 100mm f/2 Makro-Planar ZF lens showed some exposure unevenness, and shots over 1/2000 second showed a lot. Sony warns in the a7RII manual that exposures using EFCS made with non-native… [Read More]

In this post, I’ll present pairs of images made with the a7RII on both sides of the conversion gain transition, corrected in post as explained here. The base ISO is 12800. The difference in noise level is apparent.  

In the previous post we looked at color shifts in pushed Sony a7RII images, with push amounts from nothing to +5 stops, which is all you can get with the Lightroom Exposure control. See that post for the details of the conditions under which the images were captured. Now, I’d like to present blowups to… [Read More]