Mamiya 7 - shot a roll of 120 with the pressure plate in the wrong position

[mitch]

As the title says, after unloading a roll of 220 from the Mamiya I forgot to rotate the plate to the 120 setting a shot a roll of 120. There were no issues, I just shot a few extra "frames" at the end until I knew the film was completely wound onto the take-up spool, and opened the back. What I'm worried about is a loss of sharpness in the shots from that roll because the plate was in the wrong position and I assume therefore at the wrong height. But then I figured that since I had it set for 220, which I figured would set the plate slightly higher due to there being no backing paper, but used 120 film, that the film should still have been in the correct plane of focus. If it were the other way around, and I'd used 220 film with the plate in the 120 position, then I'd be seriously worried (in addition to having ended up only being able to shoot half the roll).

Anyway, should I be okay? There wasn't anything important on the roll, I was just testing out the new Portra 400, and I guess I'll know for sure when it's developed.

 

[atlcruiser]

Hi,
I do it all the time

never had any issue that i could see

david

 

[Jamie123]

Either way (120 on 220 plate or vice versa) it wouldn't really matter that much. Think about it. Backing paper is how thick? Half a millimeter at most. So it's like you're misfocusing the lens by half a mm in relation to the focusing plane. The rangefinder's probably not that accurate anyways. I think the only situation in which you might see a slight softness is if you focused anything at infinity at maximum aperture.

 

[oftheherd]

The 220 position is to move the pressure plate closer the film to keep it flat and tensioned properly. With 120, it will just hold it tighter. It will not move the film closer to the lens, or shouldn't. The rails/rollers are what determine where the film is located, regardless of whether it is 120 or 220. At least that is how it works on my Mamiya holders.

 

[johannielscom]

Interesting.

Could I subsequently also load 120 in a 220 Film holder for my Horseman?
My order of 220 hasn't arrived yet and I'd like to try the camera...

 

[sevo]

Could I subsequently also load 120 in a 220 Film holder for my Horseman?

Maybe. That is, on some cameras or magazines it can strain and wear out (or even immediately damage) the transport.

The difference between 120 and 220 is a bit bigger than length and the presence or absence of backing paper. Roll film is a bit narrower than the backing (or leader/trailer) paper, the latter being fractions of a millimetre wider than the reel so that it seals off the light at the butt ends. To make up for that width difference, 120 needs a flat pressure plate and stepped film gate (with the film path cut a bit deeper than the paper path) or vice versa. 220 needs either both flat, or a stepped pressure plate that fills the void left in the 120-stepped film gate by the missing paper.

In general, 220 in 120 magazines (or with 120 pressure plate) is more harmless than vice versa. It will be slightly loose, but that will usually only be visible with lenses that are rather unusually fast for medium format. 120 in 220 magazines on the other hand is a tight fit - sometimes tight enough to harm the transport mechanism.