I did this in reverse with my M4-P and 35 'cron. It may sound silly, but the week it took my camera to get to me gave me plenty of time to get acquainted with the lens. I sat watching TV with it to learn the aperture ring by heart, get a good feel of the focusing throw and all other minor intricacies associated with a lens. After that week of practice I can set the aperture correctly with my eyes closed, thinking of lending the lens to someone so I can have a week of fondling the M4-P to learn how to change shutter speeds without looking as well.