Some half frame cameras (well a lot of them) can be constraining due the ISO being tied to the selenium meter. Olympus, Agfa, and the Canon Demi are just a few that use the selenium meter. A work around?
Easy. Ever wonder what to do with that holga 135 that was gifted to you or you bought and it sat in the closet until now? Here's a half frame mod that even I'm capable of.
Step 1 (attached photos numbered appropriately - sorry for the crappy iphone photos - my only digital cam): cut a film box or other similar material to fit 50% of the mask. Well it's not really a mask, but whatever it's called (see photo). Gaffer tape that material in,
Don't use too much tape or too thick of material as that will add pressure against the back pressure plate making advancing the film very hard and you'll likely just shred the sprocket holes and not advance the film.
Step 2. Gaffer tape 50% of the viewfinder (you can tape the front or back side of the camera. whichever you prefer so it approximates what will be exposed on film. Important: tape the corresponding side of the finder to the mask you taped into the back.
Step 3 (optional). Get a 55mm lens shade and with a thin strip of gaffer's tape, put it on the lens.
Step 4 (optional). Scrape off the "Holga 135" lettering on the front of the Camera. Hunt down some white letraset, 24pt, helvetica. Press down the letraset letters & numbers, "M6" on a piece of gaffer'stape, spray varnish it (matte) for longevity & cut to fit over the the rectangle where "Holga 135" was.
Step 5 (optional). Put a really choice viewfinder in the flash shoe.
Step 6. Before loading film, experiment with what is just tad under half of a frame so you can get a feel for how far to advance per shot (based on thumb size and how you hold your thumb on the advance wheel - for me it's advancing two times per half-frame with a tad left over on the second advance to create spacing between shots.
Step 7. Shoot away and have fun. My results in a day or two....
[Sorry, image deleted during forum software upgrade. Please re-upload if so inclined.]