I'm trying to reverse mount a 50mm lens to a 70-300 for some macro shots. Looks like in order to do this correctly I'm going to have to manually go wide open on the aperture on the 50mm. Is there something (equipment) I should use that is dedicated to doing this or can I just try to stick a small piece of cardboard or something to wedge it open?
[attachment 16942 PICT0102.jpg]
[attachment 16942 PICT0102.jpg]