Hi All Hoping someone might have some practical advice. I shoot a fair amount of architecture, and have started using a baby large format camera (Toyo 23G with bag bellows) and 6x7 rollfilm back. (Hopefully I'm welcome here rather than the medium format thread) I've got a super angulon 90mm f8 lens (Rather than the 5.6 as I'm told the light falloff is less dramatic) I'm starting to get to grips, but i suspect it'll be a time before I start to do much more than shift. All is going well except when I do larger shifts. The super anglon clearly has the coverage, but I can see from the screen the image is nowhere near as bright (at f8 anyway). My exposures are way under, despite me thinking "Oh well, give it an extra stop" So my question is, does anybody have a decent rule of thumb to calculate the compensation for light falloff in the area I've chosen to "crop" from the image circle? Everything else seems to me a case of practice practice practice, although I've stuffed up remarkably few frames so far.