help me understand camera lenses.thanks!

[kimxii86]

Hi! i'm a novice here and was interested in buying the Canon EF 50mm f/1.8 lenses for my canon t2i with a 52mm filter size, does that mean i have to buy a step down ring for it to fit to my camera? i'm looking on bhphotovideo.com for step down rings they have a 58-55 ring, and a 55-52 ring. Do i buy two rings for the lenses to fit?

thanks in advance!

[WVCoalMiner]

Filter size is the size of a filter you will need if you buy one for your lens. ex: UV, Polarized
It has nothing to do with the mount on your lens

[Sterling]

^^Yes. It is just coincidence that the 50mm focal length is close to the 52mm filter size. They are two totally different things. The 52mm filter size is just the diameter of the threads on the front of the lens so you'll know what size of filters will screw on. Step up or down rings are made so that you can fit filter sizes not originally designed to fit.

The 50mm focal length is a little more difficult to explain but in simple terms it is the property of the lens that makes a lens a wide angle, a telephoto, or something in between. As long as the lens is made for your Canon camera, it will fit no matter what the focal length or filter size is.