Hello Apug, I have a Nikon body and some Rollei 6008 lenses and accessories. I wanted to put the lenses on my Nikon body and I purchased an adaptor from Fotodiox, which has an incorporated mechanical aperture ring. The best way I can do macro is to put my 80mm Planar, then my 34mm extension tube and then a 2x teleconverter. This setup gives me a coin occupying most of the size of a 35mm frame. However, whenever I use the integrated aperture ring with the teleconverter, the whole system becomes useless (like a tiny circle of image that gets smaller every stop). I thought that the best solution would be to purchase lens caps to match my lens and cut some holes right in the middle of them with the precision of a laser cutter, but I need some help calculating the diameters of such holes. Any suggestions? I need to use this system in a 35mm body because it offers me compatibility with my digital camera. Thank you for your time!!