N Ng Yu Lun New Member Mar 21, 2015 #1 Hi, I just brought a 17-40mm L f4 USM and realize when I look thru the lens (not the viewfinder) the hole doesn't seem very round {circular} in shape. May I know is it normal.
Hi, I just brought a 17-40mm L f4 USM and realize when I look thru the lens (not the viewfinder) the hole doesn't seem very round {circular} in shape. May I know is it normal.
catchlights Moderator Staff member Mar 21, 2015 #2 You are looking at the aperture diaphragm, if it is a bit lopsided, is normal.
