Any thoughts on the following would really be appreciated as I a pulling my hair out ( Whats left of it !! ). I am using a 90D with the 300mm IS F4 lens that has the built in Macro. Had it set to Automatic and has been working for a couple of months then all of a sudden yesterday I started getting dark pictures when used close up ( towards and in macro mode ) but further away they are not dark. So tried a 100-400mm MK II with the 90D no problem at all. So tried the 300mm lens on a 800D and again works perfectly. Looked through the settings and cannot find anything obvious. Any thoughts would be really appreciated.