I've used this for years – Lens•Lab Review

As a photographer and trainer, I'm often asked about lenses and how they work. Sometimes people get it, with just a few sentences. Sometimes it helps to show them instead. This is what I use to show them. Whenever I show the other trainers, they end up getting this too. I don't use it all the time, but when I do, I'm glad that I have it.
Review by Duzzenmatta on Lens•Lab.