Confusing state of Hasselblad A12 film back

logan2z · May 10, 2025

I haven't shot my 500 C/M for a while but took it out the other day to shoot some landscapes. I pulled it out of my bag and noticed that the frame counter window on the attached A12 back was blank so I figured I had forgotten to wind on the film when I last loaded it (the film reminder has a box top from FP4+ in it so I'm assuming there actually is film in the back). So I wound it on and it stopped at frame 1 as I expected. However, after doing that, I noticed that the magazine film status window was all red. It may have been red before I wound the film on, I didn't notice. So now I'm not sure what state the film back is in - have all of the frames on the film been shot, indicated by the all-red film status window? Is the film at frame 1 and the film status window is inconsistent with this? Is there actually no film in the magazine? Is there any way to tell what state the film roll is really in, short of opening the film back and potentially ruining the roll inside?

BrianShaw · May 10, 2025

A darkroom or changing bag would be useful at this point. Probably no film in the back and best way to be certain is to open the magazine. Did you turn the rewind crank; if there’s a roll of film you’ll feel the tension.

logan2z · May 10, 2025

BrianShaw said:
A darkroom or changing bag would be useful at this point. Probably no film in the back and best way to be certain is to open the magazine. Did you turn the rewind crank; if there’s a roll of film you’ll feel the tension.

Yeah, I’ll open the back in my changing bag and see what’s up. You’re probably right, there’s likely no film in there at all. I’m usually pretty good about pulling the box top out of the film reminder when I unload the film but may have forgotten this time.

BrianShaw · May 10, 2025

I can relate. I try to religiously manage those notations yet every once in a while it doesn’t happen. For me it’s the price paid for infrequent use of that equipment.

Tje good news is that when you pull the magazine there’s little chance of ruining the film unless the paper became loose on the spool. Turning the unload crank (previously called “rewind” erroneously) should tighten it up.

OAPOli · May 10, 2025

Most likely there is no film in the back. Maybe there is a roll on the take-up side? Only way to find out is to open it. In the dark to be safe.

You said the frame counter was blank and then went up to "1". That means the crank had already been turned a bit between the 0 and 1 positions.

Light Capture · May 10, 2025

See attached illustration from the A12 back manual.

If the half moon window is white, it's fully loaded. As it turns red, film is closer to the end of the roll.
Most people forget it's there.

logan2z · May 11, 2025

Light Capture said:
See attached illustration from the A12 back manual.

If the half moon window is white, it's fully loaded. As it turns red, film is closer to the end of the roll.
Most people forget it's there.

I didn't forget, I mentioned it in my first post

Light Capture · May 11, 2025

logan2z said:
I didn't forget, I mentioned it in my first post

Misunderstood that. Thought it referred to exposure indicator. I think it's pretty safe to say there's no film in there. I did run into one or two backs over years where that was jammed but it would be really rare.

Otherwise, functionally the back works the same whether there's any film in it or not.

Sirius Glass · May 11, 2025

I had a similar problem years ago. I do not remember the details, but there is a rod that resets the frame number when the film is removed from the back. Samys Camera took care of the adjustment.

logan2z · May 12, 2025

Well, I popped open the film back in my dark bag and - surprise! - there's no film inside. I don't see an 'ashamed' emoji at Photrio, but you can take my word for it

I guess I need to use my 500 C/M more often so I don't lose track of what state it's in.

Not sure why the film status window didn't clear when I 'wound on' the imaginary roll in the film back, but I guess that's something for another day...

BrianShaw · May 12, 2025

Yay; mystery solved!

logan2z · May 12, 2025

BrianShaw said:
Yay; mystery solved!

Yup. Thanks for your help.

OAPOli · May 13, 2025

logan2z said:
Not sure why the film status window didn't clear when I 'wound on' the imaginary roll in the film back, but I guess that's something for another day...

The indicator in the window is actuated by a spring loaded arm that follows the OD of the feed spool. Full roll = white. As the spool decreases in diameter it gradually turns to red.

Sirius Glass · May 13, 2025

OAPOli said:
The indicator in the window is actuated by a spring loaded arm that follows the OD of the feed spool. Full roll = white. As the spool decreases in diameter it gradually turns to red.

The arm should also set the frame number to '0', although I have a few film backs without '0' and have a ' ' [blank] instead.

OAPOli · May 13, 2025

Sirius Glass said:
The arm should also set the frame number to '0', although I have a few film backs without '0' and have a ' ' [blank] instead.

Actually the film use indicator arm and reset button are separate. Former is in the insert, latter is in the shell. But I didn't know some counters were blank instead of "0".

Confusing state of Hasselblad A12 film back

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