the 220 questions that seem so simple

tballphoto · Mar 28, 2021

In the manual for the 1000s, there is a few spots in the manual that make no sense at all.

The manual warns that you should NOT use 120 format film in the 220 insert because "the undue pressure of the leader could cause the leader to slip off the spool and jam it."

220 uses same paper, just a short section as leader to wind onto the take up spool. Isnt that going to happen with the 220 leader?

and my most perplexing:

"may cause the tail of the 120 backing paper to become stuck in the shutter."

Isnt that a risk with the 220 tail as well?

Don_ih · Mar 28, 2021

120 film is twice as thick as 220 where the film starts, since film and paper both continue. The pressure plate for 220 doesn't really leave room for the paper+film of 120, so it may stop advancing when that taped joint reaches the plate. If that happens, the take-up spool could continue turning and make the leader slip off the spool. It's a bit hard to imagine it could cause anything worse, though - other than strain from trying to advance the film where it doesn't want to go.

ic-racer · Mar 28, 2021

Depending on how wide the tape happens to be, your camera may be challenged with advancing 0.4mm* of material through a 0.3mm channel.

*Hp5 + Paper + Tape = 0.4mm

Donald Qualls · Mar 28, 2021

@ic-racer I think you've got that thickness figure wrong -- I haven't measured HP5+, but most 120 films seem to run .003" to .004" for the film, and close to the same figure for the backing. That's about a quarter of the figure you gave (or less than half, even including the tape).

Doesn't change the fact that you could have a hang-up trying to pull backing, plus film, plus the tape layer, though the channel intended to just pass film plus tape (should be close to .006" or .15mm), just how bad the hang-up might be. A couple thousandths of an inch oversize is a lot different from a tenth of a millimeter (or a little more including the tape). Given there's a spring behind the pressure plate, I'd be surprised if 120 would hang -- but if the manufacturer warns about it, their film channel, lead-in chamber, and spring may be such as not to tolerate about double thickness.

mohmad khatab · Mar 28, 2021

Donald Qualls said:
@ic-racer I think you've got that thickness figure wrong -- I haven't measured HP5+, but most 120 films seem to run .003" to .004" for the film, and close to the same figure for the backing. That's about a quarter of the figure you gave (or less than half, even including the tape).

Doesn't change the fact that you could have a hang-up trying to pull backing, plus film, plus the tape layer, though the channel intended to just pass film plus tape (should be close to .006" or .15mm), just how bad the hang-up might be. A couple thousandths of an inch oversize is a lot different from a tenth of a millimeter (or a little more including the tape). Given there's a spring behind the pressure plate, I'd be surprised if 120 would hang -- but if the manufacturer warns about it, their film channel, lead-in chamber, and spring may be such as not to tolerate about double thickness.

Distinguished mr Donald Qualls
Have you completed your project to develop (E6) rolls in the unconventional way or what?
Curiosity prompted me to inquire about it (I hope it does not bother you)
Thank you
Greetings

Donald Qualls · Mar 28, 2021

mohmad khatab said:
Have you completed your project to develop (E6) rolls in the unconventional way or what?
Curiosity prompted me to inquire about it (I hope it does not bother you)
Thank you
Greetings

Not yet, @mohmad khatab , have to find a place to store the RA-4 color developer (cabinet with my chemical bottles is full), and decide on a first developer solution and process.

ic-racer · Mar 28, 2021

Donald Qualls said:
@ic-racer I haven't measured HP5+.

See Post #3.

Dan Daniel · Mar 28, 2021

tballphoto said:
and my most perplexing:

"may cause the tail of the 120 backing paper to become stuck in the shutter."

Isnt that a risk with the 220 tail as well?

The end of the 220 film is taped to the backing paper. 120 film, the end of the film is not taped to the backing paper. So maybe the loose film end can curl enough to go inside the film rails and a corner of he loose film dive into the shutter?

Not sure why this wouldn't be a problem with all 120 film, not just 120 film in a 220 back.... is 220 film cut a bit wider than 120 film, to make it the same width as backing paper for the full length?

tballphoto · Mar 28, 2021

Thats what has me confused, if it can happen if a 120 roll is used in a mamiya 220 insert,, why doesnt it happen in a regular 120 insert?

What kind of tape is used to hold the tail onto the 220 roll film? And does anyone have a drawing showing dimensions for the 220 film and leader.follower

MattKing · Mar 28, 2021

tballphoto said:
Thats what has me confused, if it can happen if a 120 roll is used in a mamiya 220 insert,, why doesnt it happen in a regular 120 insert?

There are two differences between the 120 inserts and the 220 inserts.
The first relates to the frame counter interface with the camera.
The second relates to the thickness of the film gate - the 220 insert creates a thinner path for the film and paper, because the pressure plate needs to keep the film alone flat. The 120 insert creates a thicker gate, because it keeps the film plus the paper flat.
FWIW, the warnings referred to by the OP are not repeated in the manuals for the 645 Super, 645 Pro, 645e, C330 or RB67 Pro (which was where I stopped looking). All of those manuals make no reference to using 120 film in a 220 back.
For a long time Mamiya America maintained a user forum for Mamiya film camera users on their website. They had a FAQ that dealt with the 120 in 220 insert issue in respect to both their 645 cameras and their RB/RZ67 cameras. The information posted by them there was that 120 film could be used in 220 backs and inserts, but that doing so would accelerate wear on those backs and inserts.
Sadly, that user forum is long gone - it had a lot of useful stuff in it.

reddesert · Mar 29, 2021

tballphoto said:
Thats what has me confused, if it can happen if a 120 roll is used in a mamiya 220 insert,, why doesnt it happen in a regular 120 insert?

What kind of tape is used to hold the tail onto the 220 roll film? And does anyone have a drawing showing dimensions for the 220 film and leader.follower

When you expose the last exposure in a 120 insert, the camera knows it's the 15th exposure and winds the rest of the roll (paper tail) through without firing the shutter again.

If you put 120 film in a 220 insert, the camera thinks there are more exposures and so it keeps firing the shutter while you're winding the paper tail through.

There is a way to convert a 220 insert to "120" by removing a small triangle on the side of the insert that tells the camera it's 220. Then it should only fire 15 exposures. The pressure plate is still in slightly the wrong place.

Don't worry too much about these edge cases. Put 120 in a 120 insert if you have one and go make pictures.

tballphoto · Mar 29, 2021

reddesert said:
When you expose the last exposure in a 120 insert, the camera knows it's the 15th exposure and winds the rest of the roll (paper tail) through without firing the shutter again.

If you put 120 film in a 220 insert, the camera thinks there are more exposures and so it keeps firing the shutter while you're winding the paper tail through.

There is a way to convert a 220 insert to "120" by removing a small triangle on the side of the insert that tells the camera it's 220. Then it should only fire 15 exposures. The pressure plate is still in slightly the wrong place.

Don't worry too much about these edge cases. Put 120 in a 120 insert if you have one and go make pictures.

mint condition 220 inserts go for 10-20 a peice of the flea bay if they have the insert holder case. A 120 insert starts at 50$ a pop without the holder case..

the 220 questions that seem so simple

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