220 Backs with 120 film

LMNOP · Aug 4, 2014

Long time reader, first time poster.

Today I finally pulled the trigger on an RZ67 Pro ii with WLF/150mm 3.5 - all parts from multiple sources. Despite my best efforts, I could not seem to locate a 120 back from a reputable dealer that was A. in great shape. B. under $60 C. for the Pro ii (I've read the light seals are superior.)
After discussing it on the phone with a KEH rep, it seems that running 120 film through the 220 back will be just fine. He also revealed that their Japanese supplier had 'dried up' making the 120 backs harder to find, I can attest to this. I did not want to buy from Japan, so I'm hoping I can make this work. I'm in it for $40 on this 220, but my fridge is full o 120 film, and they don't make my favorites in 220!

Anyone have thoughts? My main concern is the focus, I am not so worried about advancing the lever to complete the cycle.

I would appreciate any input or experience. BTW, if you have any 150/3.5 tips, I'm curious!

markbarendt · Aug 4, 2014

No problem at all using 120 in a 220 back.

The only thing to keep in mind is that it will let you keep shooting past frame 10. Just keep your eye on the counter and when it says 11 do what it takes to keep advancing the film, at about 14 the tail will come off the supply spindle and get past the counter and the film will just start winding off. A couple more strokes and you are ready to change film.

LMNOP · Aug 4, 2014

Great to hear! I have heard focus issue theories, but the minimal difference made that seem unlikely to me. I'd imagine the negative spacing may be slightly different, but I cut my own, so also not a concern. As long as the paper doesn't end at a different point, leaving the first or last frame on paper.

markbarendt · Aug 4, 2014

The focus is based off the front, emulsion side of the film, closest to the lens and that side has fixed guides. The back side where the spring plate is doesn't matter to focus.

AgX · Aug 4, 2014

What focus theories? In both cases it is the film that rests on the focal plane guides. A issue though could be bulging paper, but any issue of that kind would exist in a type 120 camera/back anyway.

LMNOP · Aug 4, 2014

That makes sense. I find it interesting that 120 backs have become so constrained. I may try some 220 at first for bracketing sake, getting to know the half stops and such, but mainly 120 is so much more universal. Plus, as crazy as It sounds, I've gotten used to shorter rolls. These days 24 frames on 35mm feel like a lifetime.

Dan Daniel · Aug 4, 2014

The pressure plate is not supposed to 'press' on the film backing (or film itself for 220 film or 135 film) There are stops outside of the film path that put the pressure plate at a certain distance from the film rails. The film then rides in the opening, floating ever so lightly within the gap with maybe .001-2 inch to spare.

This gap where the film travels will be smaller for a 220 back than for a 120 back- the backing paper difference. On adjustable backs you can study where the pressure plate lands and measure the height difference between the 120 and 220 plate position.

If you want to make a 220 back the same as a 120 back, add a spacer material on the pressure plate area which defines the film gap- .004 inch is typical for film backing paper. A standard 3M Post-it is .0035 thick, and I have used them on a Horseman 120 220 back that I use for 120. Ideally, this spacer reduces scraping and pressure on the film. Theoretically this will lessen the chance of scratches and make the mechanism last longer. Maybe the actual pressing on the backing increases the chance of the film buckling forward. In practice, people don't account for the backing paper and get along just fine.

With some study of the internals of the 220 back, I imagine that you could determine which gear teeth or notches are only for frames 11 forward, file them off, and have pretty much a 120 back which doesn't require attention to frame 11 forward.

MattKing · Aug 4, 2014

Mamiya America used to have a FAQ on their website that dealt with this question. In addition to the concerns with the counter tending to mislead the photographer, they also warned that using large quantities of 120 film in 220 backs would tend to cause increased wear on the springs in the pressure plate assembly of the backs.

LMNOP · Aug 4, 2014

Seems to be quite a mix of opinions here, has anyone done this with an RZ67 Back?

LMNOP · Aug 4, 2014

This would be easy enough to configure, would you suggest taping it down on the non-adhesive side?

MattKing · Aug 4, 2014

LMNOP said:
Seems to be quite a mix of opinions here, has anyone done this with an RZ67 Back?

With respect to my earlier post, please note the reference to "large quantities" of 120 film, and consider that the advice was most likely directed to photographers who tended to use Mamya medium format equipment - i.e. pros who would shoot film in volume.

I wouldn't worry about short term or infrequent use.

And be sure to label the back clearly with what you have loaded - as I still shoot 220 colour some times in my RB67 and 645 Pro I could really end up confusing myself if I didn't follow my own advice.

LMNOP · Aug 4, 2014

Right. And I imagine my quantity is not quite pro level, maybe 3-4 rolls a week. This is also my starter back, I will likely get a 120 soon.

analoguey · Aug 4, 2014

But you're probably using equipment that went through a pro-level usage before you?

Also, dont be wary about buying from Japan - I have got excellent stuff off sellers from there. (my RB looks almost new)

Sent from Tap-a-talk

LMNOP · Aug 4, 2014

analoguey said:
But you're probably using equipment that went through a pro-level usage before you?

Also, dont be wary about buying from Japan - I have got excellent stuff off sellers from there. (my RB looks almost new)

Sent from Tap-a-talk

Most likely true. I am hoping the 220 can work for me but will likely find a 120 soon

ic-racer · Aug 5, 2014

The 220 back can make bulging in the center worse, with the pressure plate being even closer to the lens. I'd go ahead and use the 220 back and keep an eye out for frames where the focal point on the negative winds up being behind where you placed.

LMNOP · Aug 5, 2014

AgX said:
What focus theories? In both cases it is the film that rests on the focal plane guides. A issue though could be bulging paper, but any issue of that kind would exist in a type 120 camera/back anyway.

This is where the mixed opinions are confusing.

ic-racer said:
The 220 back can make bulging in the center worse, with the pressure plate being even closer to the lens. I'd go ahead and use the 220 back and keep an eye out for frames where the focal point on the negative winds up being behind where you placed.

Anyone have a counter to this?

Xmas · Aug 5, 2014

LMNOP said:
Anyone have a counter to this?

It is probably not true as 220 pressure plate should bottom against the cameras datum points to stop the 220 film being to far away from the lens.

With 120 film and backing the film will be squeezed against the registration surfaces with more force than is necessary.

You are going to get more wear on the film traction mechanism and film rebate damage.

Id worry more about the film acquiring a kink if your back has the same labrynthal path as the RB pro back.

Konical · Aug 5, 2014

Good Morning,

Regarding pressure plates: Check the particular camera. The Koni-Omega system, for example, is designed so that the pressure plate is in a relaxed position during film transport; pressing the shutter button moves the plate forward against the paper backing on 120 film only during the exposure. Too bad that other cameras don't employ such a provision.

Konical

roger-wilco-66 · Aug 5, 2014

If you can get a hold of only the 120 insert, you can drop it into the case you already have. It's the same. But a load of backs is always a good thing to have.

A 220 back can come handy when you want to experiment with 35mm in the RZ, by the way!

LMNOP · Aug 5, 2014

roger-wilco-66 said:
If you can get a hold of only the 120 insert, you can drop it into the case you already have. It's the same. But a load of backs is always a good thing to have.

A 220 back can come handy when you want to experiment with 35mm in the RZ, by the way!

35mm in the 220 back? Please elaborate!

Also, are you sure about the insert thing? I have seen those arpund but I figured the spacing would be different. Have you experienced this?

pdeeh · Aug 5, 2014

So a consensus has been reached: It'll be fine and it might be fine and it depends and it'll damage your camera/film/back ...

LMNOP · Aug 5, 2014

pdeeh said:
So a consensus has been reached: It'll be fine and it might be fine and it depends and it'll damage your camera/film/back ...

Haha exactly! This 220 back is being shipped to me as we speak, I'm am starting to consider buying 220 film.

MattKing · Aug 5, 2014

The "inserts" for RB or RZ backs are almost the entire back, save the shell.

So it is rare to see separate inserts.

And you can experiment by adapting 120 spools and 35mm cartridges, but good luck figuring how best to work with the interlocks!

Xmas · Aug 5, 2014

An insert is nearly as fast reloading as swapping a back if it is preloaded at the start arrows. Painful only having 10 shots.

If you can get one cheap.

The RB67 motor backs are dual standard 220 or 120 if you get the complete kit ie two (both) pressure plates.

If the back motor burns out you can still use it in manual.

k.hendrik · Aug 5, 2014

LMNOP said:
35mm in the 220 back? Please elaborate!

Also, are you sure about the insert thing? I have seen those arpund but I figured the spacing would be different. Have you experienced this?

to make things more complicated ?

(there was a url link here which no longer exists)

220 Backs with 120 film

LMNOP

markbarendt

LMNOP

markbarendt

AgX

LMNOP

Dan Daniel

MattKing

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LMNOP

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LMNOP

analoguey

LMNOP

ic-racer

LMNOP

Xmas

Konical

roger-wilco-66

LMNOP

pdeeh

LMNOP

MattKing

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Xmas

k.hendrik

220 Backs with 120 film

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