The recent post by Kerry Thalmann prompted me to a question I have been wanting to ask for a while: why 7x17? What's so different compared to 8x20? Give or take, the aspect ratio is very similar. I can imagine less weight, easier lens coverage, maybe less cumbersome film development, but could some knowledgeable soul out there (Kerry?...) articulate for me the benefits of this format? From my ignorant point of view that 17in looks like a really bizarre size, and the film can't be cut without waste...not?

(And of all the ULF formats one can choose from, Shen-Hao comes out first with a 7x17: I'm missing something, clearly...)

Thanks!