I managed to get full coverage on a 4x5" sheet with my 105/5.6 componon, should that be possible? I thought the practical limit would be 135? This was with my D3 with the variable condensor taken out, as you would do with a 150 mm lens. The focusing image was sharp in my focuscope, and I can't see any issues (e.g. uneven exposure) on the prints. Is there any downsides to using a 'too short' enlarging lens?