Removing backs on 135 film cameras

I've been playing around with various sensors and would like to try sticking some in the film plane of an old 135 film camera, such as a Konica C35, Pentax SpotMatic, Minolta SRT101, etc. The catch is, I don't know how to remove the backs.

I know the backs must come off on most old 135 cameras without too much grief because the I'm Back 35 folks basically do this with a little camera and mirror assembly (thus avoiding the crop despite using a small sensor), but I've not really found anything saying how the backs come off. Any suggestions?

ProfHankD wrote:

I've been playing around with various sensors and would like to try sticking some in the film plane of an old 135 film camera, such as a Konica C35, Pentax SpotMatic, Minolta SRT101, etc. The catch is, I don't know how to remove the backs.

I know the backs must come off on most old 135 cameras without too much grief because the I'm Back 35 folks basically do this with a little camera and mirror assembly (thus avoiding the crop despite using a small sensor), but I've not really found anything saying how the backs come off. Any suggestions?

Interesting!

Some cameras have a spring-loaded release pin by the hinge inside, which allowed the back to be removed and replaced with a date and/or bulk film back.

For those that don't you can often remove the back by sliding out a long pin that goes all the way through the hinge. Some slide out unimpeded, but for others you may need to remove the base plate first.

Older models may have fully removable backs, usually attached to the base plate. This includes models such as the Nikon F, many rangefinders including most Contax, Fed, Kiev and Zorki, etc.

I think any of the SLRs that offered a "data" back (to imprint date/time/etc. onto the film) have backs that can easily be removed to allow for swapping. If I recall correctly the Olympus OM-1 and 2, at least, can do this.

Regards,
Sterling
--
Lens Grit

Heritage Cameras wrote:

ProfHankD wrote:

I've been playing around with various sensors and would like to try sticking some in the film plane of an old 135 film camera, such as a Konica C35, Pentax SpotMatic, Minolta SRT101, etc. The catch is, I don't know how to remove the backs.

I know the backs must come off on most old 135 cameras without too much grief because the I'm Back 35 folks basically do this with a little camera and mirror assembly (thus avoiding the crop despite using a small sensor), but I've not really found anything saying how the backs come off. Any suggestions?

Interesting!

Some cameras have a spring-loaded release pin by the hinge inside, which allowed the back to be removed and replaced with a date and/or bulk film back.

For those that don't you can often remove the back by sliding out a long pin that goes all the way through the hinge. Some slide out unimpeded, but for others you may need to remove the base plate first.

Older models may have fully removable backs, usually attached to the base plate. This includes models such as the Nikon F, many rangefinders including most Contax, Fed, Kiev and Zorki, etc.

After removing the base, I managed to get the pin out of the hinge on my C35. I can just fit a cr123 battery and boost converter into the area where the 135 cart would go, although the rewind lever has a spring that keeps pushing it into that area. So, all I'd have to do is make a 3D printed back that holds everything in the right spot & firmware for the camera....  I'm working on something a tad different right now, but this (and Lafodis160) will get done & out there fairly soon....

ProfHankD wrote:

After removing the base, I managed to get the pin out of the hinge on my C35. I can just fit a cr123 battery and boost converter into the area where the 135 cart would go, although the rewind lever has a spring that keeps pushing it into that area. So, all I'd have to do is make a 3D printed back that holds everything in the right spot & firmware for the camera.... I'm working on something a tad different right now, but this (and Lafodis160) will get done & out there fairly soon....

On most cameras (I haven't tried this on a C35) you can remove the rewind crank by inserting a screwdriver into the rewind fork inside the film chamber to prevent it rotating, then unscrewing the crank assembly anti-clockwise. The fork should then pull out from within. You could then 3D-print a shorter piece with a suitably-sized hole to replace the long fork, freeing up more space inside the film chamber...

Heritage Cameras wrote:

ProfHankD wrote:

After removing the base, I managed to get the pin out of the hinge on my C35. I can just fit a cr123 battery and boost converter into the area where the 135 cart would go, although the rewind lever has a spring that keeps pushing it into that area. So, all I'd have to do is make a 3D printed back that holds everything in the right spot & firmware for the camera.... I'm working on something a tad different right now, but this (and Lafodis160) will get done & out there fairly soon....

On most cameras (I haven't tried this on a C35) you can remove the rewind crank by inserting a screwdriver into the rewind fork inside the film chamber to prevent it rotating, then unscrewing the crank assembly anti-clockwise. The fork should then pull out from within. You could then 3D-print a shorter piece with a suitably-sized hole to replace the long fork, freeing up more space inside the film chamber...

It took quite a bit of force, but yup, that worked. There is a pretty heavy detent in the rod, which is why it took so much force.

ProfHankD wrote:

I've been playing around with various sensors and would like to try sticking some in the film plane of an old 135 film camera, such as a Konica C35, Pentax SpotMatic, Minolta SRT101, etc. The catch is, I don't know how to remove the backs.

I know the backs must come off on most old 135 cameras without too much grief because the I'm Back 35 folks basically do this with a little camera and mirror assembly (thus avoiding the crop despite using a small sensor), but I've not really found anything saying how the backs come off. Any suggestions?

Just flip the switch on the bottom