This is a continuation in a discussion of spatial frequency response (SFR) and modulation transfer function (MTF) testing reproduciblity. The series starts here: Towards a reproducible MTF testing protocol The basic lighting technique that I’ve been using for my razor blade MTF testing has been to backlight a piece of white paper with two LED… [Read More]

There has been a little interest in developing a protocol for slanted edge modulation transfer function (MTF) testing that is sufficiently standardized and reproducible that the results from various amateur practitioners can be compared fairly. There are several things that conspire to make slanted edge MTF testing irreproducible: Alignment errors Field curvature Target differences Lighting… [Read More]

After seeing the aliasing and false color with the Otus 85 wide open on the Sony a7RII in yesterday’s post, it’s reasonable to ask how much the lens aberrations at f/1.4 are reducing aliasing and false color, even if it’s obvious that they are not eliminating them. To do that, we can look at a… [Read More]

I’ve had a request for an additional function on this blog: the ability to be notified via email when someone replies to your comment. I think I’ve added that function. When you comment now, you should see something like this at the bottom of the commenting page: You’ll have several choices from the drop down… [Read More]