Archives for August 25, 2017

This is a continuation of this post: Off-axis aberration testing — Sony 12-24/4 on a7RII If you got here without reading the previous post, you should go back and do so now. Here is the full frame at 18 mm:   Here’s our magnified tight crop of the center, with the same pixel dimensions as before:… [Read More]

This is a continuation of the development of a simple, relatively foolproof, astigmatism, field curvature, and field tilt test for lens screening. The first post is here. I’m trying to refine my off-axis test procedures with the idea of getting them posted in a single document and inviting users to try them out. I’m sure… [Read More]