Bronica ETR ETRS question

dphphoto · Oct 8, 2011

Is there any difference between a 120 back for an ETR/ETRS and a 220 back besides the insert?
Just curious, thanks.

Dean

lxdude · Oct 8, 2011

Nope.

dphphoto · Oct 9, 2011

Didn't think so, but wanted to be sure. 220 backs are cheaper on eBay, and I have an extra 120 insert.
thanks

BrianL · Oct 9, 2011

The back is the same. You can use either insert with it.

Photo Engineer · Oct 9, 2011

Yes, there is a difference. The safety interlocks on the ETRS and ETRSi are better than on the ETR. I have sets of all of the backs and those for the ETR can let you fire the shutter with the dark slide in and also you can remove the back with no darkslide. Kinda makes you keep your eyes open and your mind alert!

KEH shipped me an ETR back that was supposed to be an ETRS back. I learned the hard way! But, they were very nice about it and gave me a huge discount when I agreed to keep the ETR back.

PE

lxdude · Oct 9, 2011

PE, you are correct on the differences between earlier/later backs, but Dean was asking if there was a difference between 120 and 220 backs other than the insert, that is, does anything other than the insert determine if a back is 120 or 220.

There are some differences in backs which could be associated with the differences in E-series models because of introduction times, though all backs fit any early or late E series camera, excepting the C, which could only exchange inserts, not backs.

The early ones for ETR and ETR-S from 1979 to 1982 have the single release tab with coaxial lock.
When the ETR-S was changed to polycarbonate body panels in 1982, the backs and inserts also changed to partly polycarbonate. The release was changed to the two-tab style. A problem was that the collar around the dark slide pin which kept the camera from firing with the dark slide in was also plastic and could get damaged or broken. I have some of those and with reasonable care the collar is fine.
With the ETR-Si in 1989 the collar was changed to metal, and a full dark slide lock (with the grey handle dark slide) was introduced.

Jerry Thirsty · Oct 9, 2011

dphphoto said:
Didn't think so, but wanted to be sure. 220 backs are cheaper on eBay, and I have an extra 120 insert.
thanks

If you have an insert, then you don't need to buy a full back (even 220). KEH lists the back shell by itself.

BrianL · Oct 9, 2011

I have a couple of the early 2 tab backs along with the original 1 tab and never had the plastic collar break. I suspect to breal it, it requires a bit of heavy abuse. The 1 tab back though supposively change because it was could open I never had a problem with as it has a safety lock that needs to be moved before the tab can be moved. I suspect persons finding problems with it did not close the back correctly. Maybe because I am used to the Bronica, I never found the locking slide of the 3rd type a non-issue. Of the 3, I actually prefer the earliest. Used right there is no chance of it opening while with the 2-tab versions there is no lock preventing the back from opening.

Photo Engineer · Oct 9, 2011

LX;

Thanks. You are correct.

I have 3 backs here and the 120 ETR and 120 ETR-Si (to be more exact in nomenclature) are identical except as I described and you described in terms of materials and interlocks.

But, the inserts appear identical between 120 and 220. Short of taking the film out and examining them, I cannot judge. However, the 120 and 220 backs themselves differ in terms of having different counters for the frames. Of course we all know about the differences between the 120 and 220 inserts themselves regarding paperless 220 vs paper backed 120.

PE

lxdude · Oct 9, 2011

Photo Engineer said:
LX;

Thanks. You are correct.

I have 3 backs here and the 120 ETR and 120 ETR-Si (to be more exact in nomenclature) are identical except as I described and you described in terms of materials and interlocks.

But, the inserts appear identical between 120 and 220. Short of taking the film out and examining them, I cannot judge.

Don't yours have the labels on the side?

However, the 120 and 220 backs themselves differ in terms of having different counters for the frames.

But it's the inserts that have the counters.

Photo Engineer · Oct 9, 2011

They do indeed have labels on the sides of the backs, but the inserts have no labels that I could see. The counters appear to be on the backs, not on the inserts. This implies that if the insert is removed from the back, only the back will have visible ID. I'm not going to open 4 backs to check this out. Lots of film in there.

PE

lxdude · Oct 9, 2011

What you're thinking is the back is actually part of the insert. The back beyond its lower hinge is really just a shell, with hooks on the front top edge to engage with the locks, a couple flat springs on the inside to hold the insert in place, and on the outside the holder for the film box end. It's open on either side, and closes over the insert edges so the side of the back is really the side of the insert.

Photo Engineer · Oct 9, 2011

The advance mechanism and counter are on the back and the counter is geared to the back.

I guess I have to sacrifice some film. Grrrrrrrrrrrrrrrrrrrrr!

PE

lxdude · Oct 9, 2011

And the gear and counter are part of the insert! Counter-Grrrrrrrr!

Photo Engineer · Oct 9, 2011

Well, the numbers in the counter window are part of the back. That is the problem here. If the counter does not have the right values, then there is a problem. But, without taking it apart and testing it..............

BTW, there are 2 gears - one in the back and one in the insert. They mesh.

lxdude · Oct 9, 2011

The back has no gears. The gear is part of the insert and projects through a slot in the back to mesh with the gear on the body. The numbers in the counter window are part of the insert. The insert has all the gears, the counter, the pressure plate, the crank on the side, and holds the film spools. The back seats the insert and holds it onto the camera, provides the safety interlocks, and provides the dark slide, but the insert is wound directly by the camera.

lxdude · Oct 9, 2011

www.youtube.com/watch?v=VmT72aqfq_g

Go to 2:40 to see the insert being quickly removed and reinserted. Go to 5:00 and you will see the insert being removed prior to loading. Watch closely and you'll see the slot for the gear in the back when the insert is out.

EDIT:
This is even clearer.
www.youtube.com/watch?v=lNEEbT7yrNg&feature=related

Go to 2:20-at about 2:30 you'll momentarily see the gear slot in the back.

Photo Engineer · Oct 9, 2011

I'll defer to you until I can see the video and take one apart.

Thanks.

PE

Photo Engineer · Oct 10, 2011

You got me so curious that I got out a back.

LO and BEHOLD - a gear protruding from the back on the side with the windup crank. This appears to couple with the insert!

Since this back is loaded with 800 Portra, I am loathe to open it. Sorry.

And, the counter on mine is integral to the back, not the insert.

PE

lxdude · Oct 10, 2011

It appears to be, but isn't. See the diagonal seam on the RH upper surface ahead of the counter? It's right next to the RH lock on dual-lock style backs. The front of the seam (toward the body) is the back and the rear of the seam is insert. Look at the RH underside, next to the hinge, and you will clearly see the insert set into the back, and the back overlapping the insert.

There is an exception, and that is with either 35mm back (24x36 or pano), which open the same way with the lock on the top, but the sides are solidly attached. A special 35mm insert with its own pressure plate mates to gears on the inside; the counter and the crank for winding while loading are part of the back, as is a rewind button and crank.

BrianL · Oct 10, 2011

Okay, I just opened a 120 back and the insert has the winding mechanism, the counter and the gear that fits through a slot and mates with a gear in the camera body. The back has a pair of leaf springs but it is to hold the insert tight while the insert has the pressur plate springs. The back itself is an empty shell with no mechanisms whatsoever. So, a 120 or a 220 insert will fit and work. Hope it answers the question. The 35mm back is different and neither the 120 nor the 220 insert will fit.

By way of logic, think of the ETRS-C body with the fixed back. It will take either the 120 or 220 insert so the counter, etc. must be part of the insert or it would not work with both.

For what it is worth, I prefer loading a few backs and carrying them than playing with inserts while out. Much easier and faster to swap, especially with the 1 tab early back, and less chance of light intrusion.

Photo Engineer · Oct 10, 2011

Yeah, you guys are right. It has been too long since I just removed the insert. I have 5 backs filled with film and didn't want to crack any open.

Thanks for putting that right.

PE

lxdude · Oct 11, 2011

Sounds like y'all need to git shootin', PE!

Photo Engineer · Oct 11, 2011

My case is too heavy to carry nowdays and I spend most of my time making and testing emulsions and writing. I need an assistant or an apprentice!

PE

BrianL · Oct 11, 2011

PE, I feel for you. I too am starting to feel the weight of the Bronica when I even pick it up. I am hoping my strength will return after the cancer treatment. In the meantime I am looking at bringing the Rolleiflex back to life and moving the Leica up to my 35mm system. Previously, I used a 35mm back on my Bronica so it was my main 35mm system. Sad because the Bronica has been a close friend since the '80s.

Tough to get older or have medical handicaps.

Bronica ETR ETRS question

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