ASSEMBLY INSTRUCTIONS
120 - Rev A
Overview
This is a Baby Graflok conversion for Polaroid 110A 110B and 120 model cameras intended for use with 120 roll film holders.
This project was a continuation of my 4x5 conversion kit project. For 110B models, the larger 4x5 film holder does not interfere with the viewfinder. However the 110A viewfinder is closer to the center of the camera and is partially obscured by the 4x5 kit. This kit, while limited compared to the 4x5 conversion, allows full access to the 110A viewfinder, is smaller, less expensive, and more cost effective to shoot than 4X5.
This kit utilizes many of the same components as the 4x5 kit, most notably the lower chassis. If a camera has been previously modified for my 4x5 kit, these components are a direct swap with no additional work or modifications required.
Film Back Compatibility
This kit was designed around the Horseman (8exp 6x9, 10exp 6x7) and Mamiya RB67 film backs. There is a nominal spec size for these film holders so all 2x3 graflok style backs should be light tight but the differences in models seems to come down to dark slide design and overall dimensions behind the film plane. I will update this entry as I get confirmation of compatibility with other models.
9/5/26 update - added an alternate set of rotating locks that are 1.1mm shorter for better compatibility with RB67 backs or any film back with shallow grooves.
Camera Selection and Destructive Modification
The conversion is inteded for the 110A and 110B models. This conversion is destructive and the camera will not be able to be easily returned to the stock afterwards.
The conversion is inteded for the 110A and 110B models. This conversion is destructive and the camera will not be able to be easily returned to the stock afterwards.
There are a number of similar models that will, at least, be partially compatible. The 120 is virtually identical to the 110A model but built for export markets by Yashica. The primary differences is they are equipped with a Seikosha shutter that, in my opinion, is better quality than the Prontor shutter of the Polaroid built models. The 900 utilizes the same integrated rangefinder/viewfinder assembly as the 110B but was equipped with an Electric Eye shutter and lens assembly that is partially automated. The 900 chassis is identical to the 110 models but would require a custom lens board and a replacement shutter and lens assembly. Alternatively, you can use the 900 as a donor to swap the rangefinder to a 110A model - see this page for information. The older 110 models (no A or B suffix) has a rangefinder assembly on the right side of the camera. This will require a slightly altered upper and lower chassis of my kit to work, files for this model are a current WIP. I have not had direct expereince with other models such as the 95, 150, 160, etc yet to be able to definitely say if they are compatible or not.
Viewfinder Framing Reference
The frame lines in the 100B/900 series viewfinder coincide closely to the actual framing of a 120 6x9 negative. After assembly,check the framing in the viewfinder against the included ground glass. If you choose to add an accessory viewfinder, the horizontal field of view with the standard 127mm lens is ~38mm for 35mm/full frame equivalent for 4" x 5" or 54mm for 120 6x9. See reference photo below:
The frame lines in the 100B/900 series viewfinder coincide closely to the actual framing of a 120 6x9 negative. After assembly,check the framing in the viewfinder against the included ground glass. If you choose to add an accessory viewfinder, the horizontal field of view with the standard 127mm lens is ~38mm for 35mm/full frame equivalent for 4" x 5" or 54mm for 120 6x9. See reference photo below:
Tools Required
For purchased complete kits - Multiple sizes of small flat and phillips screw drivers, metric hex drivers, drill + drill bits, magnifying loupe, knife, sandpaper, small files
For purchased complete kits - Multiple sizes of small flat and phillips screw drivers, metric hex drivers, drill + drill bits, magnifying loupe, knife, sandpaper, small files
Teardown, Preperation, and Installation
1. Open the rear film chamber to access the inside. Remove any film guides above and below the film gate. Fully tape off the lens and bellows across the film gate to protect them from metal shavings.
2. Drill or dremel off the rivet heads (red) for the hinges on the left side. Peel back the leatherette from the hinge carefully to fully separate the hinge and left door from the camera.
3. Remove the two screws to remove the film spool holder (green circles). Certain models have rivets through the top and bottom into the body (green arrows), if it is riveted you'll need to carefully drill out and/or pry on the film spool to remove it.
4. Drill out the two tapped holes for the original film spool holder holes to 1/8" thru holes.
5. The leatherette over the hinge can be glued back down with contact cement or double sided tape. If the leatherette tears and the hinge rivet holes are visible you will need to cover these holes in leatherette or tape to block any stray light. Alternatively these rivet holes can be drilled and tapped for M2 flat head screws.
6. Drill or dremel off the rivet heads for the right side door. To remove this hinge, you may need to pry it away from the body along the green line using a small pry tool, be careful not to bend or tweak the camera body.
7. Cut the leatherette near the film door latch along the red line. Remove the leatherette to the left of this line to expose the latch plate and the two hidden fasteners underneath. Remove the four slotted screws retaining the latch plate and keep the screws for later use.
8. For 110A and 900 models only: If you are omiting the side strap and lug, lift the
leatherette on the bottom in this area to acces the hidden strap lug screws and
remove lower lug. This area will be covered by the new bottom plate.
leatherette on the bottom in this area to acces the hidden strap lug screws and
remove lower lug. This area will be covered by the new bottom plate.
9. Before installing the conversion parts, the rangefinder should be calibrated. Set the focus to infinity and point the camera towards a large object in the far distance, preferably something large with distinct edges/features you can check against. Adjust the rangefinder mirror screws to correct any misalignment. See links below for writeups by others for top plate removal and rangefinder adjustment screw information. Reinstall top plate.
10. Drill out the two rivets (red) at the front of the stock lens stop/catch. Remove the two screws (green) to remove infinity stop and keep screws for later.
11. Install included light seal foam in location shown below.
12. The chassis will arrive partially pre-assembled. Install conversion kit as shown in assembly drawings. Chassis mounts to the camera using 2X BT3X16 through the holes drilled out in step 2 and the four original latch plate screws removed in step 4. The supplied 1/4-20 X 1/2 bolt secures the new bottom plate to the original tripod socket.
Do not overtorque fasteners
The included self tapping screws are going into plastic so only need to be lightly snugged. The brass threaded inserts are more resilient but can be partially pulled out of place if overtorqued. The conversion kit is intended to fit snug but may require minor filing/sanding to the chassis around the latch plate for the best fit. Please report any major issues with fitment and I will replace any parts as required with revised versions.
Final Calibration
1. Once assembled, loosely install the new lens stop using the original screws and insert the included focusing screen into the back.
2. Verify the rangefinder is still aligned at infinity.
3. Set the camera on a tripod and set up a focus target. Focus on the target with the rangefinder, set the aperture wide open and lock the shutter open with a shutter release cable.
4. Adjust the position of the lens stop until the focus target is sharp, checking against the focusing screen. Verify with a high magnification loupe and tighten screws on lens stop when sharp. Verify focus is accurate between the rangefinder and focusing screen at close focus through to infinity. If the focus is out of wack with the rangefinder when comparing multiple focus distances, the round rangefinder cam under the top plate may need further adjustment. Please contact me if you have any issues.
Revision Log
Rev A – Initial Release
Rev A – Initial Release
