Medium Format Film

[480sparky]

When Kodak's data sheet says that T-max size 120 is thicker than other roll films, they are saying it is thicker than Ilford 120 and thicker than Foma 120 and thicker than Adox 120. They are not saying it is thicker than Kodak 220 T-max which they did not make.

Seems strange that the thickness would vary. Maybe the variations are minute enough to not matter, but I'd think focus could be an issue when shooting with fast lenses wide-open.

Surely we focus onto the surface of the film which is always (dangerous word!) held against the film gate in the same position regardless of the emulsion thickness or substrate thickness?

Yes, but the film gate only touches the film at the edges. Lacking a film gate everywhere else on the film, if the pressure plate is too far back, the curl of the film could cause the film to 'pull back' from the actual focus plane.

Again, maybe such differences are minute enough to matter in the dangerous world we live in. I don't know. Nor do I care to know. I haven't shot 220 film since, oh,......... 1985. I don't have any 220 backs for my Boat Anchor. So it's all academic to me.