polaroid model 150
120 roll-film conversion


This was my first attempt at camera hacking. This Model 150 Polaroid Land Camera was my great grandfather's and was given to me along with other cameras from family members. I never knew him and the film for these cameras was discontinued in the early 1990s. My father was convinced that something was wrong with the shutter, so I figured it wouldnt hurt anything to fiddle with it. I decided that I wanted to convert the camera to use with modern films, and since at the time I didnt own a medium format camera, I decided to try my hand at converting it to run 120 film.

To do this conversion yourself you will need a small Drill Press, a Dremel tool, and other basic tools. I cut both wood and sheet-metal parts for this and you should have some idea of how to use the correct tools to do the job. Dremel cutting disks and grinding wheels are a god-send for this project. Be sure to wear eye protection whenever using power tools! Those Dremel disks break easily and so do the small drill bits you will need for drilling out old rivits in the Polaroid body.

Polaroid Model 150 inside
With original Type 40 spool and 35mm film canister for scale

The first project to do is to strip out all of the rollers and the film guide on the left side of the body. You can remove all of these by carefully drilling out the rivets with a small drill bit. I used a small Drill Press to help do all the drilling. You can remove the doors by pushing a tiny nail into the hinge and then pulling the hinge pin out with pliers, being careful not to bend it. Leave the tiny roller on the pressure plate door. Make sure not to damage the hinges, or the locking mechanism.

Stripped down camera

To the left of the camera you can see some of the parts for the Roll-Film Holder. It is made from sheet metal, wood and some bolts. The sheet metal stips are about 18mm wide, and basically hold the wooden blocks in place without interfering with the film. The wooden blocks are cut to fit inside the film chambers. The bolts are the correct size to fit inside of the holes at the ends of a 120 spool.

Unpainted Roll-Film Holder

This is just 4 wooden blocks cut to fit into the cavities for the old Type 40 rolls.... with 4 strips of sheet metal holding them together (using upholstry tacks and glue). The bottom 2 blocks have bolts going through them and sticking up about 1/8" to hold the 120 rolls. For the top left block I built a spring mechanism with a bolt though it to allow for loading the film. The top right block just has a 3/8 hole drilled in it to allow for the film advancer, as well as a spring to hold the roll in.

Film Advance

Which is just a long bolt with a slot cut in the bottom with a Dremel cutting disk (it took about 4 of them, so if you intend on doing this, buy extra and wear good eye protection!) I drilled a hole through the top of the camera and tried to aim exactly where the old Type 40 spool holder was at. Again be sure to use the size bolt needed to fit inside of the 120 spool. The sheet metal tab put into the slot is fit to the 120 spool and I rounded the corners. The nut at the top is used to attach the knob, I used a tinkertoy wheel. You must attach the knob BEFORE final assembly because you will want to use epoxy or liquid nails to glue the tab into the slot in the screw. Save that step until the end when you know everything works!

NOTE: On drilling through the top of the camera. I got lazy and didnt take the plastic top-plate off. If you aim exactly for the roll holder on the inside you will drill into a cavity which the flash synch cord runs through. I never use a flash, so i just kept going and ate up the wires. Another problem I ran into was bits of aluminum and plastic chips made their way into the rangefinder and viewfinder. Take my advice... remove the top-plate and drill the hole in the body, and then mark the spot and drill the top-plate separately.

You will find the hidden screw holding the top-plate on if you open the front door of the camera and look up inside directly between the rangefinder and viewfinder windows. The second screw is found by opening the back of the camera and looking under the left corner right beside the strap lug. The third is located inside the flash shoe.

Unpainted assembly
Including poorly-made 6x6 adaptor

I do not recommend trying to make a 6x6 adaptor... its just alot of extra work for something that further crops an already VERY cropped image. Besides, the 6x10.5 format is soooo much prettier to look at!

The parts painted flat black
When painting these parts be sure to prime first before painting.

Pressure-Plate Door Extension

The back of this camera has so many holes and hinges and doors in it and weird places for light to come in, I just decided to close off the compartment all together. This peice slides onto the end of the door and fits snugly around the 120 adaptor. It was pretty tricky to make, and doesnt fit perfectly. I drilled three holes in it to match holes already in the pressure-plate door and attached with tiny bolts. You can find tiny bolts and nuts at Lowes in the Specialty Hardware drawers. The ones marked Size 4 and Size 6 are great for cameras.

Film tensioner spring

I drilled the rivets out of the spring on the pressure-plate door and trimmed it down to fit 120 film. Then I bolted it to the new part of the door. Cover all of your holes with Gaffers Tape or with scraps of 120 backing paper and electrical tape.

Shooting with the Model 150

The Polaroid shutter uses EV numbers which combine aperture and shutter, instead of traditional stops and shutter speeds. Check the link below for more information on the Polaroid shutter and for information on more Roll-Film models. Ive only done two test rolls through this camera, and both of them suffered from issues of frame overlapping. You should test your advance with the backing paper from a used 120 roll. Some people drill out a hole to use the frame advance numbers on the 120 spools, but I have issues with drilling that many holes through the back of this huge camera, and it seems like an invitation for light leaks!

I also replaced the hand strap with a standard camera strap to make it easier to carry this monster! You will need to carry a light-meter or a second camera capable of metering. Fortunately with this conversion your rangefinder should be perfectly accurate!

All about Polaroid Roll-Film Cameras

A complete disaster
photo credit : Helen Dempsey

Back to Experimental Photography section