You may want to get a different lens cap. I had a similar problem with my SLR. I have a lens hood on my SLR and filter. The Nikon lens cap works just fine, but I wanted a newer one. So I went and bought a new one, and it wouldn't fit! The little levers that you press stick out and touch the rubber lens hood. So, I took the new cap back and stuck my old cap back on. Perhaps go to a good camera shop, and try a few different brands of lens caps. (Personally, I prefer the slim line of filters, though the regular type probably offers more protection for the lens, for som cams anyway---especially if it's got a big lip like with the regular size B+W filters.)