And as for filters for protection, I'm of the crowd that thinks it's kinda pointless. Any whack good enough to actually fubar the lens will fubar it right through a filter. And it will take a lot of years of lesser nicks to degrade the end to a point it really really matters. All the while you have stuck a flat piece of glass on the end happily ready to at least offer no help to quality. Other than a seal if you plan to use it in a hurricane or sand storm, for protection, kinda pointless. And say you nick the crap out of the end over the years, I can't see it being extremely costly to send it to canon to have that piece swapped out anyway. I use my 10-22 all the time, never ever use a lens cover cause I'll just lose them anyway. Always yanking it in and out of the car and all over. I've managed two little nicks. Little nicks vs a big(relative to the nicks) piece of flat glass. And that's not really ever even trying to be real careful. I do wish I had a filter on after shooting around some sand dunes a bit though. But that is it.