M645 Users: How many frames do you get on 120 film?

<p>I have a basic question for you Mamiya M645 users. When I get my 120 film scanned, there appear to be at least 2-3 empty frames at the beginning of the roll. I got 14 frames on my last roll, by the way. I am wondering if I am pre-winding too much when I load the film?? After I get the film leader into the take-up spool (wrong term?), I wind the film by hand until the "start" line on the film lines up with the arrow on my 120 cartridge. Then, once I insert the cartridge, there is some additional winding to get the frame counter to #1. Any feedback as to whether I am wasting film?</p>

<p>You're doing everything right. You're supposed to get 15 frames on a 120 back. Check the negatives and see if the spacing between negs is consistent. If it's not, you need to have the insert repaired.</p>

<p>Thanks, appreciate your response :)</p>

<p>Older Mamiya 645 bodies are notorious for developing erratic frame spacing. You can try another film insert to see if that corrects it, but I suspect the camera itself needs servicing. I've experienced this with several M645 and 1000S bodies.</p>

<p>You should be getting 15, as per the frame counter Chip.<br /> I've never experienced erratic frame spacing on an M645, 645J or 1000S myself, but Mamiya did choose to leave a wasteful amount of space between frames. You ought to be able to get sixteen 6x4.5 frames on a roll of 120.</p>

<p>Make sure the little rubber-rimmed metering wheel in the film-insert has sufficient spring pressure to keep it in contact with the film. Check the film is spooling properly as well. If it's at all loose when you remove the used spool, then there's a tensioning problem. The spring-loaded rollers may need bending to ensure they're contacting the film with sufficient pressure. A common problem also is that the guide rollers top and bottom of the gate in the camera don't turn freely, and this leads to wear on the small pressure springs. The rollers should be just free of touching the gate, not jammed against it.</p>

<p>FWIW the M645s are nowhere near as unreliable as old Kowa or Pentacon 6 cameras for dodgy frame spacing, and the crappy Kiev 6 didn't even have a frame-measuring mechanism at all! it just relied on 2 turns of the take-up spool.</p>

<p>Oh, one other very basic thing to check. You are using the correct markings on the film leader to line up the start? Some films have a very indistinct start line that's easily confused with other markings on the backing paper. I usually line the start marker a little before the arrows on the insert, so that I get a bit less "header" before the first frame.</p>

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<p>Mamiya did choose to leave a wasteful amount of space between frames. You ought to be able to get sixteen 6x4.5 frames on a roll of 120.</p>

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<p>You do get 16 on the Mamiya 645AF(D) line, however. The standard HM401 film backs are self-contained with internal motors - there's no geared coupling to the body - so the film spacing is more tightly controlled than in the older manual focus cameras.</p>

<p>However, some users complained that the change to 16 frames increased the chances of the kink (that develops in the film when it sits around a roller for a protracted period) falling within a frame, instead of in the gaps between frames. So Mamiya produced a revised film back, the HM402, which offers the choice of either 15 or 16 frames. These backs appeared with the 4th generation 645AFD III, at a time when most new buyers were getting the body with a digital back instead and the overall medium format film market had shrunk considerably, so they are much rarer and more expensive than the ubiquitous HM401 backs. The HM402s also wind a bit faster and imprint more metadata in databack mode.</p>

<p>We had a <a href="/medium-format-photography-forum/00YUob">good thread here about this a few years ago</a>. It illustrates the kink problem clearly and the 15-vs-16 frames debate. Just ignore the combative posts by Q. G. de Bakker.</p>

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