I know this has been discussed before and I did try to find the various threads without success. I'm picking a secondhand 57 tomorrow after years of waiting. For some reason I've been fixated on it. Question is Sigma lens compatibility. I've got a 70/300mm APO Macro a 170-500mm non digital version and a 14mm 3.5. Now I know there's the chewing of the gears thing on some lenses but are there any other issues.