So I just started playing with some reversing rings. I am wondering about the effects of the amount of space between both lenses through either adapter ring thickness, or using lenses with their front element recessed vs non-recessed? Does the space between the optical elements make a huge difference?
Right now I'm not sure if I should ebay reversing rings with 2 male threads, or get step down/up rings + couplers. Same for reverse EF mounts. You can get a mount per filter size, or just get one filter size and use step up/down rings to adapt it to your other lenses.