Originally posted by swanlefitte Good links. I find it funny how he uses both metric and imperial in the same sentence. 8x10 viewed at 25cm. Why not viewed at 10?
What's weirder to me is how popular 8x10 still is as a format. I usually have to go to a crop I don't particularly like to put an image in an 8x10 frame. Even in film my preference was 8x12. But these things no longer refer to the actual measurements, they refer to ratios as well.
The lack of other than 4x5, 8x10, 16x20 frames (4:5 ratio) got me into custom mats back when I was printing. I just couldn't find what I wanted off the shelf.
The 25mm close focusing distance is not a ratio, so CM makes more sense (or at least if does if you're from a metric country.)
That's my take.