In my last post I wrote about my attempts to measure vignetting in the lenses I use with my DSLR camera. Another lens problem that the camera can correct (but only for Canon lenses) is lateral chromatic aberration. To determine the amount of correction my lenses need I printed out a simple test chart and … Read more
A few years ago I wrote about some experiments I’d done with measuring and correcting vignetting in digital photographs. (Some cameras have such correction built in, called “peripheral illumination correction” or similar.) I recently purchased a second-hand 10-18 mm wide angle lens for my DSLR. Measuring its vignetting using my previous method is difficult as … Read more
In a previous blog post I outlined how I correct vignetting in digital photographs. In this post I will describe in more detail the software I’ve written to do this. The corrector is part of my Pyctools project and you can download example scripts that use it from my Pyctools-demo project. The picture below shows … Read more
I recently purchased a budget telephoto lens for my Canon EOS 100D DSLR camera. It’s a 500mm f/6.3 mirror lens, essentially a small Cassegrain telescope. Like many budget lenses it suffers from “vignetting”, i.e. the edges of a photograph are darker than the centre. The EOS 100D camera has built in vignette correction (called peripheral … Read more