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Are film gate modifications necessary when Adapting Super Ikonta D (616) to 120 and 35mm

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Yobo57

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Joined
Oct 26, 2024
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I was thinking of trying to shoot some 120 and 35mm on a 616 Super Ikonta.

For 120 is it necessary to extend the rails to keep the film flat to achieve proper sharpness and focus? I’ve heard people recommend it but have also seen in some cases it cause more problems than it solves.

I was thinking also maybe just 3D printing a modified 120 to 616 spool adapter so that the film rests on the top of the film gate and only have the bottom unsupported. Anyone try that before?

For 35mm I see most people don’t modify the film gate when adapting to 120 but also usually the film gate is not 12cm long. Do you think it matters when adapting to 616 or it should be fine no supports?

Let me know what y’all think
 
For 120 is it necessary to extend the rails to keep the film flat to achieve proper sharpness and focus? I’ve heard people recommend it but have also seen in some cases it cause more problems than it solves.
FWIW:I have a super Ikonta A (645) and I noticed that the pressure plate rests on the outer rails, which are wider than the 120 film and higher than the inner rails (by an amount definitely more than the film+backing thickness). So I think that the design intent is that the pressure plate defines the image plane (plus paper thickness), and on the natural film curvature (from being spooled) to press it against the plate.
So, why not try? However, the 616 gate is longer than the "6x9" format. So, if you go by the numbers intended for "6x9" you will have overlap between neighbor images. Plus, I'd bet that the "red window" for 616 does not let you see the "6x9" frame numbers.

Alternatively, why not use 70mm film, the native width of that camera? I read that some folks are happy with Agfa/Aviphot film, with suitably tuned development. All you need is some backing paper and the second spool.

It also depends whether you want that camera to become your daily user camera or you jut want to run a couple of rolls through it.
 
FWIW:I have a super Ikonta A (645) and I noticed that the pressure plate rests on the outer rails, which are wider than the 120 film and higher than the inner rails (by an amount definitely more than the film+backing thickness). So I think that the design intent is that the pressure plate defines the image plane (plus paper thickness), and on the natural film curvature (from being spooled) to press it against the plate.
So, why not try? However, the 616 gate is longer than the "6x9" format. So, if you go by the numbers intended for "6x9" you will have overlap between neighbor images. Plus, I'd bet that the "red window" for 616 does not let you see the "6x9" frame numbers.

Alternatively, why not use 70mm film, the native width of that camera? I read that some folks are happy with Agfa/Aviphot film, with suitably tuned development. All you need is some backing paper and the second spool.

It also depends whether you want that camera to become your daily user camera or you jut want to run a couple of rolls through it.
Definitely gonna give it a try, have a few rolls I have to get around to finishing first though. The red windows should line up with the 6 x 4.5 numbers on the 120 backing paper, so I think I'll try and just shoot at 3,6,9,12 and 15 and see what happens. 3D printed some custom adapters that seem to fit ok. The film chambers are pretty narrow so 120 spools just barely squeeze in. 35mm cassettes don't really fit with the extra little gate where the leader comes out. I'm thinking maybe I will pop open the cassette in the darkroom and load just the inner spool, , I'm worried maybe the tension will be off, we'll see.
 
I've done this for 120 only, I fabricated a mask using black cardboard from a stationary store, and black electrical tape, the tape with one side smooth and shiny. The cardboard mask is a one piece "full" mask. It needed to be accurately measured and marked before cutting to size and bending each side at 90degrees, making it a neat fit in the camera's film gate. Then holding it in place while the tape is applied to all edges to fix the mask there. The 90degree bend on all sides gives the mask strength, but it must be a neat push fit in the film gate, otherwise, only the tape is being relied on for rigidity and strength. The tape should only be the fixing agent. For adapters, I used ebay ones but you might have to buy 2 or 3 sets from different makers because some don't fit right. For one set I had to use my Dremel to deepen the slot to properly accept the key of the film advance handle. The fabrication of the mask, with all four sides bent at 90degrees, means that a little of the negative's frame length is sacrificed at both ends, but that will give you more room and leeway for frame spacing. The longitudinal edges of the mask must be such that the clear edges of the film, do not encroach too far into the negative's area itself. That said, mine does, but only a little, and what I ended up with, were very neat negatives with a little extra clear film on all sides. The camera is a 2A folder. I've yet to make a mask for my Zeiss 530/15 D.
 
I've done this for 120 only, I fabricated a mask using black cardboard from a stationary store, and black electrical tape, the tape with one side smooth and shiny. The cardboard mask is a one piece "full" mask. It needed to be accurately measured and marked before cutting to size and bending each side at 90degrees, making it a neat fit in the camera's film gate. Then holding it in place while the tape is applied to all edges to fix the mask there. The 90degree bend on all sides gives the mask strength, but it must be a neat push fit in the film gate, otherwise, only the tape is being relied on for rigidity and strength. The tape should only be the fixing agent. For adapters, I used ebay ones but you might have to buy 2 or 3 sets from different makers because some don't fit right. For one set I had to use my Dremel to deepen the slot to properly accept the key of the film advance handle. The fabrication of the mask, with all four sides bent at 90degrees, means that a little of the negative's frame length is sacrificed at both ends, but that will give you more room and leeway for frame spacing. The longitudinal edges of the mask must be such that the clear edges of the film, do not encroach too far into the negative's area itself. That said, mine does, but only a little, and what I ended up with, were very neat negatives with a little extra clear film on all sides. The camera is a 2A folder. I've yet to make a mask for my Zeiss 530/15 D.

Thanks for the input, do you happen to have a picture of your mask to better visualize it?
 
No unfortunately, at the moment the mask is in the camera. I'm trying out my first roll of Gold 200 and I'm up to frame 4. It's one item I didn't take pictures of as I was making it. Until I finish the film, I can't remove it and show it to you. If you like, you could make it in four pieces and stick them together to form an oblong to fit neatly in the camera. It's a matter of bending four strips of that thin black cardboard to form a 90degree angle for each strip, ensuring they'll have extra length for tabs on the ends to be bent around for gluing one piece to the other. It's taped at the ends first, right across, then the lengthwise tape is cut to fit in between the cross pieces. The thickness of the tape will hardly make any difference to the focal length, it will still be good f5.6, I mainly use f8 and f11 to be sure. The tape is thin and the shiny side is nice and smooth for the film to slide along. You could glue the mask in with craft glue and forget the tape, but it would be more permanent then.
 
Here's a picture of the film guide rails I made from brass sheet, and a card "pressure plate that I used on my Kodak 2C. The top and bottom guide rails are made from two pieces (each), so that the bottom rail is the same level as the original film gate.

Kodak 2C film gate mods.jpeg
Kodak 2C pressure plate mod.jpeg


Hope this helps.
 
@P C Headland That is very much like what prototyped using cardboard for a Kodak 122-120 camera conversation. It worked well even using the camera’s native “pressure” plate. On my camera it seems that film flatness, such as it is, was controlled as much by film tension as it was by pressure; maybe more so by tension.
 
Hope this helps.

Looks like nice work. Someone else mentioned being able to use the 6x4.5 frame track if you can see it through the red window. A hole in that "pressure plate" would allow that.
 
To put it in better perspective, this is the same camera as the OP's. 120 film is a smidgen narrower than the camera's film gate. The backing paper only just touches the film gate either side. I think this is the reason the OP is asking the question perhaps. But because the 120 film is still a bit narrower than the film gate, a mask would be beneficial for film flatness.

!20 spool up against 116 film gate. Note the 116 spool on the extreme left. The pressure plate covers the whole film gate area

IMG_8250.JPG
 
Last edited:
No unfortunately, at the moment the mask is in the camera. I'm trying out my first roll of Gold 200 and I'm up to frame 4. It's one item I didn't take pictures of as I was making it. Until I finish the film, I can't remove it and show it to you. If you like, you could make it in four pieces and stick them together to form an oblong to fit neatly in the camera. It's a matter of bending four strips of that thin black cardboard to form a 90degree angle for each strip, ensuring they'll have extra length for tabs on the ends to be bent around for gluing one piece to the other. It's taped at the ends first, right across, then the lengthwise tape is cut to fit in between the cross pieces. The thickness of the tape will hardly make any difference to the focal length, it will still be good f5.6, I mainly use f8 and f11 to be sure. The tape is thin and the shiny side is nice and smooth for the film to slide along. You could glue the mask in with craft glue and forget the tape, but it would be more permanent then.

No worries, thanks for the detailed explanation
 
Looks like nice work. Someone else mentioned being able to use the 6x4.5 frame track if you can see it through the red window. A hole in that "pressure plate" would allow that.

I used the autographic window and made a new red window on the 6x6 track. I taped off the original window. IIRC I use 1,3,5,7,9,11 (it's a while since I've shot with it).
 
No worries, thanks for the detailed explanation
I'll be away next weekend. I'm taking my camera with me so I'll shoot off the last 4 shots then I'll be able to post a pic of the mask. If you do decide to make a mask for your Zeiss D, the dimensions and configuration of it might end up being a little different to mine because the Zeiss has a narrower surface area and a dimpled film gate frame, versus the flat wider surface of the Kodak 2A my mask is in. That's not to say a mask can't be designed for the Zeiss, it only needs to be figured out how best to do it.
 
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