Lens-to-GG distance?

[Cableaddict]

I recently bought a used Letus, which came with a Nikon mount. My best lenses are all EF mount, so as a temporary fix I duct-taped a 58/1.2 to an old macro extension tube & mounted it to the Letus.

This seems to work pretty well, but I know that the lens is maybe 10mm farther away from the GG than it should be. I can still focus within the range that I need to (MFD is maybe 3' further away) and it seems like I can get a sharp focus.

Is there something I should be concerned about? - enough to spend $95 onan EOS mount? (money is VERY tight right now)

 

[Ryan Patrick O'Hara]

If your flange to GG distance if off, you will be able to get sharp focus, however your focal marks on the lens will be off, causing you to either not be able to focus all the way to infinity, or you'll be able to go past infinity.

You can always look up what your flange depth is supposed to be and measure it out. But if you don't have the exact tools, I'd measure on the long side, because if I were to not care about the markings on the barrel, I'd rather pass infinity than not be able to reach it!