Well, I usually shoot medium format on vaction, and with these negative I regularly correct keystoning in the darkroom. Luckily my negative and lens stages are very easy to tilt. It's not that hard, but as pointed out above, the amount of adjustment is not as great as with a view camera, and you end up enlarging part of the negative more than the other, which can look odd if enlarged too much. I used this technique here: http://www.apug.org/gallery/showphot...00&ppuser=2946