Convert Bronica ETR 220 insert to 120

dabsond · Dec 14, 2016

Anyone know if any way to convert a Bronica ETR 220 insert to utilize 120 film. Any way to reduce the pressure on the pressure plate?

Steve Smith · Dec 14, 2016

The incorrectly titled pressure plate rests on some outer rails leaving a space for the film to pass between the plate and an inner set of rails. For 120 film, this gap is just a bit wider than the film and backing paper combined. For 220 film without backing paper, its just slightly bigger than the film.

If you were to add some tape or something similar to the outer rails which was about the same thickness as backing paper, this would increase the gap to allow the film to pass through without jamming.

Steve.

dabsond · Dec 14, 2016

Might have to give it a try, since cheap 220 inserts are readily available. I would assume the frame counter would be off. Easy to go past the 16th frame if you are not careful. Thanks.

hsandler · Dec 14, 2016

I think Steve's reply is a good one. As an anecdotal data point, I have an SQ-A myself and I've put 120 film through a 220 back unmodified, not even tape on the rails, without issue. Sharpness seemed unaffected. The pressure plate seems to have enough give not to press too hard on the outer rail or bow the film. You just have to do several dummy exposures and wind on after each after you expose the last real frame to account for winding the backing paper.

brofkand · Dec 14, 2016

hsandler said:
I think Steve's reply is a good one. As an anecdotal data point, I have an SQ-A myself and I've put 120 film through a 220 back unmodified, not even tape on the rails, without issue. Sharpness seemed unaffected. The pressure plate seems to have enough give not to press too hard on the outer rail or bow the film. You just have to do several dummy exposures and wind on after each after you expose the last real frame to account for winding the backing paper.

This is very good to know considering 220 backs are cheaper than ever these days, now that 220 is gone.

TSSPro · Dec 14, 2016

I've done that same, however I found that my SQ A 220 inserts died so much quicker than my 120 inserts. Maybe I was getting my used stuff that was used by high volume wedding shooters, or who knows, but that was my experience. I went through about half-a-dozen of them before I gave up on Bronica 220 inserts.

paul ron · Dec 14, 2016

when using 120 in a 220 back, the starting point is different as well. start your 120 at the very tip of the leader, not at the arrow. this will take you to the first frame as normal.

RichardJack · Dec 21, 2016

Used backs are so cheap, just buy another.

StephenT · Dec 22, 2016

paul ron said:
when using 120 in a 220 back, the starting point is different as well. start your 120 at the very tip of the leader, not at the arrow. this will take you to the first frame as normal.

For some reason (maybe age!) I can't seem to visualize starting "at the very tip of the leader." Isn't the very tip what you wind on the takeup spool? Sorry if this is a stupid question but I am missing something.

pdeeh · Dec 23, 2016

This chap has a possibly useful resource list on his website Dead Link Removed

As always, one has to make a judgement as to whether information found lying about on the web is to be trusted, but he seems to be talking from personal experience at the very least,

Gary Ayton said:
using 120 film in 220 backs:
there appears to be no focus error issues in using 120 film in Bronica SQ or SQA 220 film backs
you can also use 120 inserts in 220 backs
there are 2 main problems:
film counter issues:
is that the camera will assume you can take 24 images as for 220 film in a 6x6 back instead of only 12 for 120 film (30 on a 6x4.5 220 back instead of only 15 frames on 120 film) and thus unless you are alert to this you will end up taking a lot of blank photos - you need to watch the film counter and stop.
You'll have to wind the film out and expose until about the 15th frame before opening the back, you'll feel a reduction in tension if hand winding once end of film is reached.
where to start the roll so you don't lose the first one or two frames or the last one or two frames:
a suggested technique by Budd Gottesman to check frame spacing is the following:
"use a test 120 film which you won't develop to mark the spacing of frames
load your 120 roll on your 220 insert as usual but bring the arrows to a point approximately 90 degrees (1/4 turn) BEFORE the start marker on the insert.
Wind the camera to #1 as usual.
Then without a lens on the camera (set to multi-exposure if necessary) fire a shot and mark ON YOUR WASTE ROLL where the frame is located, so when you then remove it (possibly, and I'd recommend) go thru the rest of the roll marking shot by shot, on the film which will assure you how the "SPACING" is working on this back.
BTW: You may need to change the starting point slightly forward/back as you need.
If you give the backs/inserts heavy use, I'd DEFINITELY tell you to check the spacing like this on them all every few months."

paul ron · Dec 23, 2016

StephenT said:
For some reason (maybe age!) I can't seem to visualize starting "at the very tip of the leader." Isn't the very tip what you wind on the takeup spool? Sorry if this is a stupid question but I am missing something.

start the leader on the take up spool as close as possable to the end of the tongue so it holds n not slip off the spool... yes. dont advance to the arrow line up point. just close the door n wind up to frame 1. if you start at the arrow line up, you will lose 2 frames.

do you have any backer paper to test innyour back? try it n you will see what im saying.

StephenT · Dec 23, 2016

"do you have any backer paper to test innyour back? try it n you will see what im saying."

Ah........the picture is becoming clearer! Thanks! I do have some backer paper and will give it a test.

ic-racer · Dec 23, 2016

Glue two strips of backing paper to the outer rails.

paul ron · Dec 24, 2016

you can also draw teh frames as tehy come into the film gate to see what your spacing will be.. it may be a bit off but thats because of the circumference difference of 220 n 120 on he take up. they wont overlap though.

wiltw · Dec 24, 2016

Paul Ron said:
when using 120 in a 220 back, the starting point is different as well. start your 120 at the very tip of the leader, not at the arrow. this will take you to the first frame as normal.

Paul Ron said:
yes. dont advance to the arrow line up point. just close the door n wind up to frame 1. if you start at the arrow line up, you will lose 2 frames.

Fortunately I have kept some old sacrificial rolls of Kodak film around in both 120 and 220 format, which I could unroll in the light to make measurements

120:

Start mark (arrow tips) is 247mm from the tip of the backing paper.
Film is attached to backing paper 430mm from the tip of the backing paper.
Film starts 183mm from the start mark.

220:

Start mark (arrow tips) is 375mm from the tip of the leader
Film is attached to the leader paper 540mm from the tip of the leader
Film starts 165mm from the start mark.

So one problem to resolve in any film insert conversion effort is the 18mm difference in the starting point of the film, compared to any start mark on the leader/backing paper. That point is your reference point for when you have 'run out of film' relative to the higher capacity exposure counter in 220 backs. Not sure where the statement comes from about 'losing 2 exposures' ...18mm difference in film starting point is only 40% of a 645 frame (42-43mm) of 32% of a 6x6 frame (56mm)!

If you put 120 film in a 220 back, you need to stop initially winding film 18mm before you even see the start mark! If you do not, Exposure 1 starts 18mm late, and the last frame is 18mm later than it should be...so perhaps you need to say to yourself 'Exposure 11 is my last shot', rather than Exposure 12 for 6x6 frame. But then you have short changed yourself one shot on every roll, making film 8.3% more expensive per roll (assuming 11 shots rather than 12 shots/roll) to buy and to process when loading 120 film into 200 backs.

Convert Bronica ETR 220 insert to 120

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