This post will probably upset a few of you. Don’t care. Lens compression is a myth, I’ve been saying it for years, but when I try to explain why, peoples’ eyes start to glaze over. This video from Dave McKeegan, however, explains and demonstrates the principle wonderfully. Although, as Dave says, it really doesn’t matter.
Dave does go very in-depth into explaining the technical side of why lens compression doesn’t really exist, and if you’re not technically minded in the least, you’ll probably want to watch some parts of the video two or three times to fully understand what the demonstrations… uh, demonstrate. But it’s worth sticking with it. The better you know the principles, the better you’ll be able to use your gear.