Cinema Products CP-16R Viewfinder Repair

(Downloadable manuals can be found on the other Cinema Products page)

By removing the 4 screws you can lift away the viewfinder ‘douser’ for cleaning in the event it sticks or is jammed.

Once cleaned and lubricated place the shutter blades back in position. The indicated cut aways line up with the pins of the ‘douser’ adjusting ring in the following picture.

Once the blades have been cleaned and lubricated, place the reassembled ‘douser’ into your palm and lower the eye piece onto the ‘douser’ turning the douser upside down may make the blades fall out and need to be placed back in the right order.

If the ‘douser’ is fully functioning and does not need cleaning, simply unscrew the whole assembly to gain access to the view finder glass to enable cleaning.

In the event that the diopter cannot move back and forth or loses it’s adjustment, the metal sheath can be unscrewed and slid off. As per the indicating arrow, there is a brass screw that enables the diopter to travel in and out without falling apart. ensure the screw moves freely, adding a small touch of lubricant only.

Once the brass screw is removed, the one here had to be drilled out, a small ball bearing will then drop out and the sliding tube can be removed, sometimes with gentle persuasion. The ball bearing remains in the groove and can be held in place with a little grease.

Once disassembled clean all parts and lightly lubricate with a touch of grease or drop of light oil. The brass collar, far left, needed deburring on the inside as the soft brass had been gouged by a seized knob. The sliding tube, second from right, gets re-greased or oiled and will slid much smoother. Included is a small shim.

Looking through the viewfinder one can see a large black corrosion or smudge. After cleaning the lens parts that can be reached, without effect, disassembly is next.

Remove the small grub screw and slide out the remaining lens element.

Next, dismantle the viewfinder. Remove the 4 screws, 2 on each elbow. Each elbow is very hard to remove. I used nail polish remover which is an ideal glue weakener, and a Q tip to dab solvent along the elbow joints. After letting the solvent seep into the elbow joints for a minute or two, I then used the plastic end of a screwdriver to tap the elbows off the viewfinder. Looking at the the black corrosion, via the arrows, the problem is clear.

The pyramid shaped glass is not glued in, but sits on an adhesive pad and is a very snug fit in the metal elbow. Do not use anything to lever them out, they are glass and will break. Use the plastic end of a screwdriver and attempt to tap the glass from the metal body. Be sure to tap in the direction that the glass can go. The glass will slide out either side.

Once the glass surfaces are cleaned up, it seems the silver paint that was originally applied to create a mirror backing has corroded off, in the same shape as the adhesive pad that the glass sits on. Seems the pad erodes the silver paint. Re-applying a type of mirror finish paint or tint is required.

Initially I experimented with a few items to replace the eroded silver paint. First I tried silver model paint, but it was no good, not reflective enough. I tried cutting glass from a mirror, but the thickness of the glass altered the magnification path and had to be abandoned. I tried silver cellophane, which worked very well, however, small imperfections in the cellophane distorted the magnified image and failed to accurately display an image. Had to be abandoned too. I will next try mirror finish paint.

Next I tried Rust-Oleum ‘Mirror Finish’ spray paint. I was a little dubious as to how well it would work. Cleaning up the prism, I applied 5 thin coats, around a minute apart, at a distance of 30 centimeters. After around 15 minutes it was dry, I waited a few hours for it to harden before handling it. Note: A youtube video suggested not touching the dry paint as it will leave an imperfection that will be noticeable, even when dry.

Once the prisms were able to be handled I re-installed them in the metal viewfinder elbows and tested the results. I was very impressed with the final product. I could not see any issue with the result, and the reflections appeared almost perfect. I considered that until the reflected image could be seen under magnification, I would not get too excited.

Once the viewfinder was re-assembled I lit a small scene with a lamp, making sure I had some vertical lines in the frame. All in all I was very happy with the result. The areas where the corrosion had been replaced with spray paint were very hard to see. As with all film shooting, ensure the diopter is set properly for the camera person’s eye, and use a tape measure for setting focus if unsure of the image seen in the viewfinder.

The surfaces that the elbows mate to will have left over glue. This should be removed to ensure close mating surfaces. Use nail polish remover or a light grade sandpaper. Only sand enough to remove the glue, not the metal.

Prior to re-attaching the elbows with the repaired silver paint backing, use a small paint brush to apply a very thin layer of general purpose silicon to help provide a seal against dust once the viewfinder is re-assembled. Use a paper towel to wipe of excess. Only a VERY thin layer is needed.

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