I'm pretty comfortable on set but after directing a handful of shorts as well as some TV commercials, etc, I realized that I didn't actually know anything about cameras. I'd find myself saying things like, "Can we move closer?" or, "Can we be wider?".
Sure, you can get by like that if you are working with great DPs (and a lot of great directors do) but for me to feel like I really know what I'm talking about, I felt it necessary to buy a camera and really learn how capturing light works. So I bought a camera and some old-school manual lenses and started figuring out / experimenting with shutter speed, aperture, composition, exposure, field of view, depth of field, etc..
I think it's fascinating and although I'm far for from considering myself an actual photographer, I am happy to share the pictures I've been taking while on this journey. Here's a sample but please visit my 500px page to check out more!