12-08-2018 11:38 AM
Recently purchased a used ef 400l f/2.8 IS USM. Just got it yesterday, haven't used it yet. When I was inspecting it I noticed there was a slight booger of some sort on the drop in filter holder, towards the top off to the left side. Did the obvious, tried to clean it with 0 luck. Just wondering if the filter holder from a second generation lens will work?