I've got a 300mm f2.8L IS lens and it came with a drop in gel filter holder. I'd like to replace it with a drop in holder that takes 52mm glass filters. That's no problem. I'm looking at the B&W filters and they come in slim (UV Haze 010 (MRC) Multi-Resistant Coating Glass Filter Slim) and regular width (UV Haze 010 (MRC) Multi-Resistant Coating Glass Filter) versions, with the slim being more expensive. Now I'll buy the slim version if I have to but I'd like to ask if anyone has used the regular thickness filter in the drop in holder?