The Minox frame counter: who knows how to read it correctly?

Actually, I just wanted to give a tip about the Minox frame counter. It's about a mistake I always made when reading the frame number without realizing it. But once I started thinking about it, more and more questions came up.

First, here's the initial question. What number does this frame counter on a Minox A show?


Until now, I would have said: 0. Unfortunately, that's wrong—it shows 1!
And what is this figure supposed to tell us? The number of pictures taken so far? Wrong!

Why is this important? What are the two functions of the Minox frame counter? What does this mean for the correct insertion of the film? How are the photos stored on the Minox negative strip? How long and how thick is a Minox film? How much space is there between the negatives? ... These are not academic questions, but facts that can have a serious impact on the practice of Minox photography!

In the end, it turned into a whole article with lots of pictures and facts. EVERYTHING you need to know about the Minox counter and film. If anything is missing, please post it here. I will try to add it. Here is the article (select the language at the top left):

Well, this is interesting. I've got (so far) four of the old metal cassettes, the ones originally sold with 50 frame rolls (they're unused NOS, so they've still got long-expired film strips inside). This suggests that even with those cassettes I might be unable to load 50 exposure rolls of color film (not that I'm likely to shoot color in the Minox). UNLESS the metal cassette has thinner material and thus a fraction of a millimeter larger inside diameter. I won't know that for a while -- I'll have to slit and load at least a couple rolls first.

I do note, however, that it looks like a 50 exposure load is almost exactly the length of a 120 film -- which is why I'm aiming mainly for 50 exposures with my Minox B and 6-strip from 120 slitter, and why I bought the 50 exposure cassettes.

Unfortunately, I don't own any of these Minox metal cassettes. However, I can't imagine that the casing walls are thinner than those of the later plastic cassettes. So there probably won't be any more space inside them either. This means that ADOX CMS 20 will probably be used to accommodate 50 exposures.

This is the sectional drawing of the metal cassette from the original patent specification. You can see that the film chambers have double walls.


If you ever open one of your cassettes, please let us know how big the inner diameter of the film chambers is.

tjwspm said:

Unfortunately, I don't own any of these Minox metal cassettes. However, I can't imagine that the casing walls are thinner than those of the later plastic cassettes. So there probably won't be any more space inside them either. This means that ADOX CMS 20 will probably be used to accommodate 50 exposures.

This is the sectional drawing of the metal cassette from the original patent specification. You can see that the film chambers have double walls.
View attachment 414013

If you ever open one of your cassettes, please let us know how big the inner diameter of the film chambers is.

Click to expand...

These are the dimensions I measured previously, so they may not be entirely accurate.

On the LX the “0” indicates no more left; frame 36 or 15 depending on which of the two start dots were used.

APL said:

These are the dimensions I measured previously, so they may not be entirely accurate.

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If those measurements are even fairly accurate, I should be okay with most modern B&W films in the metal cassettes -- those seem to have more than a millimeter larger inside diameter than the modern plastic ones. I'll know when I get my darkroom cleaned up enough to slit a roll and run it through the camera into the takeup chamber (likely going to start with XP-2 Super, which has no reason to have the thickness of color, but will let me get EI 640-800 via bleach bypass).

APL said:

These are the dimensions I measured previously, so they may not be entirely accurate.

Click to expand...

Thanks for taking the measurements. If you don't mind, I'll add your measurements to the article on my website. Then we'll have everything in one place.

Donald Qualls said:

If those measurements are even fairly accurate, I should be okay with most modern B&W films in the metal cassettes -- those seem to have more than a millimeter larger inside diameter than the modern plastic ones. I'll know when I get my darkroom cleaned up enough to slit a roll and run it through the camera into the takeup chamber (likely going to start with XP-2 Super, which has no reason to have the thickness of color, but will let me get EI 640-800 via bleach bypass).

Click to expand...

Once you have cut a roll and placed it in the metal cartridge, please post your findings here. That would be very interesting.

tjwspm said:

Once you have cut a roll and placed it in the metal cartridge, please post your findings here. That would be very interesting.

Click to expand...

Getting it into the supply chamber isn't the problem -- it's being able to wind the full 30 inches (~760 mm) of the strip onto the takeup spool without jamming that's the question.

tjwspm said:

Thanks for taking the measurements. If you don't mind, I'll add your measurements to the article on my website. Then we'll have everything in one place.

Click to expand...

No problem

Thanks tjwspm, that's an interesting article. I never knew about the cam that makes frame spacing consistent.

Bill Burk said:

Thanks tjwspm, that's an interesting article. I never knew about the cam that makes frame spacing consistent.

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I had assumed something like that. I've had a number of Minolta 16 and Kiev 16 mm cameras that use a similar mechanism -- in their case, the cam is visible when the shell is off the camera body for loading, and automatically resets to zero then the shell is removed. A slightly different method is used in 120 cameras with "turns counter" frame counters (like the Graflex 23, 22, and RH series roll backs, as well as -- at least -- Zeiss 532/16 Super Ikonta B), where a wheel has notches with decreasing spacing.