I have made a couple of attempts to shoot an ultra-wide angle shot with lots of front rise. My first attempt was wildly underexposed -- perhaps by 2-3 stops. This wasnít a metering error. On the second attempt, I bracketed +1 stop, +2 stops, and +2.5 stops. I got the shot with the +2.5 exposure, but donít understand the reasons.
The lens is a Schneider 38XL using roughly a 6x9 crop out of a 6x12 frame. I used a centre filter. The lens just ran out of image circle at the top of the photograph.
I suspect the cause must be some exposure compensation requirement for rise-type movement, perhaps exacerbated by the extreme hot-spot characteristics of the 38mm and the use of the image circle extremity. Iíve never seen any details of such compensation though, while there is plenty of mention of bellows-extension-related compensation.
Can anyone shed any light on the cause? If it helps, the shot is here.