This question already has an answer here:

So recently I bought a used lens - Canon ef 28-80mm f/3.5-5.6 usm with the metal mount but it came with no lens cap and I want to buy one now but I can't see the diameter of the lens on it anywhere which I need to buy a lens cap, do any of you guys have this lens or happen to know the diameter of it?


marked as duplicate by chuqui, TFuto, AJ Henderson, Hugo, mattdm Dec 31 '14 at 18:58

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


A quick search on the internet suggests it is 58mm. It is often referred to as the 'filter diameter'. Also, as a general rule, on the lens somewhere, maybe around the front optic, there is usually a little 'o' with a line through it like this ø followed by a number of mm. That should be the size to look for. Also, if you have a camera shop nearby you can take the lens in with you, they will probably have various sizes in stock, and will find one to fit it.

Not the answer you're looking for? Browse other questions tagged or ask your own question.