Bronica ETRSi 120 Winding Issue

[Lebet]

Purchased a 120 back on ebay and it stops winding the film at around frame 5 or 6. The rewind crank will still move, but the film doesn't advance (the multiple exposre lever is straight up and I've shot a roll of 120 with my other 220 back without issue). If I pop the back open and close it, the camera will make me advance to frame 1 before it will fire the shutter and I've burned up the other shots on the roll.

I wound on some paper backing and opened the back flap and held the camera lens down and advanced several times through a full rolls worth of frames without issue. When I close the back with just paper in it I can get it to advance to frame 10 but then it sticks again and won't advance.

Is it worth pulling the back apart?

Should I just shoot with my 220 back and what would be the downside if I shot 120 with a 220 back?

Thank you for taking time to read and respond.

Kirk

 

[markbarendt]

Should I just shoot with my 220 back and what would be the downside if I shot 120 with a 220 back?

I know it's not the same , but 220 backs work great for 120 on my RB, just have to remember that I have 120 in it because it will keep counting past the end of the roll.

Experiment with the backing paper and you'll probably see what I mean.

 

[StephenT]

Mark, when you load the 120 in the 220 back, do you stop at the index mark when winding on the film? I seem to recall that 120 and 220 have different wind stops, but it's been a long time since I used 220.

 

[markbarendt]

Yes, line up the start marks and close the back.

220 film rolls have a longer leader with an "earlier" mark. That earlier mark is used on special equipment like roll film backs for 4x5 cameras.

 

[paul ron]

to use 120 in a 220 back, you need to start the leader at the very begining of the keader n not aligning the normal start arrow.

if you start at the arrow you will lose frames at the begining of the roll.

best way to see this is to run a paper backer test roll without the lens so you can see n mark each frame as you advance the roll through.

 

[Lebet]

Thank you everyone. I've got a few rolls that have gone through the 220 back so I'll be able to see how it goes. I put some paper through the back yesterday and marked off the frames as well. Thank you for all the ideas.

 

[paul ron]

have fun!

 

[StephenT]

mark and paul: here's a copy/paste from another post: " ..I just measured that 220 film starts at 553mm from start of leader, 120 film starts at 427mm from start of leader, so the first shot will be wrongly placed!"

If that's true, then there is a 126mm difference in leader length, or about 5 inches, and my 120 RB back will wind 120 film almost two frames too far. Right? It hardly takes a turn on a RB back to get to the start mark on the film reel.

Should I tape the 120 leader to the takeup reel - would that save a frame maybe?

 

[markbarendt]

mark and paul: here's a copy/paste from another post: " ..I just measured that 220 film starts at 553mm from start of leader, 120 film starts at 427mm from start of leader, so the first shot will be wrongly placed!"

If that's true, then there is a 126mm difference in leader length, or about 5 inches, and my 120 RB back will wind 120 film almost two frames too far. Right? It hardly takes a turn on a RB back to get to the start mark on the film reel.

Should I tape the 120 leader to the takeup reel - would that save a frame maybe?

On the RB, the placement of the start line closest to the start of the film works fine. Other cameras will require a test.

 

[paul ron]

good observation! thats why it has to start at the very begining of the leader. to get the first frame about right.

how about cutting a short leader extension from another roll? you're on the right track.

 

[StephenT]

mark and paul: I did a test by running a roll of backing paper through the RB. Apparently using the starting mark on the paper aligned with the starting arrow on the back works fine. The initial winds of the lever bring the paper to where the exposure number on the paper looks about right on the pressure plate.

I assume the leader on 220 is marked on the paper so that it will have the start mark 5 inches beyond what 120 paper would have. I can't imagine any other way 220 could wind correctly otherwise.