In yesterday’s post, I downsampled images successively, a factor of two at each step, in an attempt to get averaging at the same time. I was working with the images today, and it didn’t look like I was getting the desired effect. Then it hit me. I was doing exactly the wrong thing. Downsamping by… [Read More]

As many of you know, I’ve been doing slit scans of plants, and I’ve been struggling with image artifacts due to subject motion. In the past few days I’ve been working on a Matlab program to deal with the artifacts and at the same time assemble several images into a complete, visually seamless composite. In… [Read More]

Yesterday’s experiments with the D810 dark-field noise, which showed that Nikon employs some low-pass filtering when long exposure noise reduction is turned on, made me wonder if there was any similar filtering at high ISO settings, a la the Sony a7S. I looked at one of the green channels of exposures made at ISO 64… [Read More]

Yesterday I reported on some of the processing the D810 does to raw files, apparently in an attempt to reduce noise. A few weeks ago, I published these curves which look at dark-field noise vs shutter speed with the in-camera long exposure noise reduction on and off. You will note that there is some processing… [Read More]