Bronica 35mm Mask

Farts and Crapts

Uploaded January 18 2025

When I got my beloved Zenza Bronica ETR medium format camera, I also got a 35mm back to go with it. This means I can shoot 2 rolls at once, without ruining it. However, since the camera is intended to be for medium format, this means that the physical area that the 35mm shot takes doesn't fill the frame of the viewfinder.

Normally you'd solve this by buying a different focusing screen to give you frame lines, but I can't justify paying $100 for some glass with lines.

Originally I wanted to solve this by taking a sharp blade to the bottom of the viewfinder or the current focusing screen. I knew that this would be a permanent solution so I took some time to think it over. Like a year later, I saw that some TLR cameras can be converted from 6x6 to 6x4.5 format with a part that would cover the extra parts of the frame both on the film and the viewfinder. This seemed so simple I questioned why I didn't even think about it.

Unlike the TLR cameras, the 35mm back already covers the extra parts so all I needed to do was to make something to go between the viewfinder and the focusing screen. There was some black cardstock that fit in between somewhat nicely. The only problem is to cut it to the right shape and size. If it's too small then it will wiggle around, making it inaccurate to what the film sees.

The outer rectangle was easy, the hard part is the open frame. The focusing screen isn't exactly 1:1 with the full 120 frame size so I had to measure the size of the 35mm frame in relation to the full 120 frame, and scale it according to the focusing screen. After all that was sorted, I had to actually cut it. My margins are in the millimeters so it took me a couple tries to get it close. I don't remember exactly, but I think it's oversized slightly than what the film records. I also added a cutout at the top to make it easier to take out. In the image below, the left one was my first try, and the right was the final one.

When the mask is inside the camera it definitely looks a little high up, but I think I'll shoot a roll with it first and see how inaccurate it is. It may end up being at the actual frame border.

When I was thinking about writing this, I came up with a bunch of sex jokes to tell the story of how I made it. This ended up being too difficult to write in a sensical way, so I'm gonna leave them here unconnected to anything and you can figure out their meaning.

"if only it were a milimeter longer" (a review from a previous partner)

"it was straight enough" (also review from a previous partner).

"this new one was actually perfect, but it already had a cut on it" (again, a review)

"unfortunately the next one didn't work out since it ripped"

"however i decided to keep that part since the tab was useful for taking it out"

"i trained myself on a previous failure so i could get it right"

"i ended up cutting a little far, but its fine" (is this even making sense now?)