Canon FT QL mirror damper replacement

I thought I’d make my first post about some work done on my favourite camera: my dad’s old Canon FT QL.

20181106 Canon FT mirror damper 3

This fully mechanical SLR was built from 1966-72. It has through-the-lens metering (the only electrical function) and a nifty Quick Load system for film insertion (honestly not sure why it’s not ubiquitous in later cameras – it’s foolproof). A camera like this was a great place to start learning how to use cameras properly, as you have to do everything. Doubly so, as the light meter is getting a little iffy. I just “sunny 16” it up when the light meter gets sketchy and it generally works a treat.

This camera has had some work done on it back in the 70s or 80s – badly. Dad kept the receipt. The workman’s notes can be paraphrased as “Couldn’t fix the issue, you’ll need parts to fix this :O also, I tried cleaning the insides and now your focusing screen’s light meter match circle is gone YOLO kthxbai.”

Somewhere along the line it also lost its mirror damper, though from disintegration or incompetence it’s hard to say. The mirror would whack up against the frame surrounding the focusing screen, which was quite noisy. I think, over the years, it also made the mirror mount slightly loose, as the mirror would sometimes travel outward, as it were, and get stuck against the mirror damper’s baffle plate and not return, causing the viewfinder to be black after a shot. How the mirror never broke I am not sure.

For my first attempt at replacing the mirror damper, I used some 2mm black craft foam bought from a local art store. I cut it to size (about 2.5-3mm wide) with a craft knife (not very well – turns out a rotary cutter is a far better tool for this). I attached it with as small an amount possible of PVA glue. While not a great glue for metal, it adhered the foam to the camera well enough.

20181105 Canon FT mirror damper 1

However, after reattaching the baffle plate and testing, I wasn’t sure this foam was thick enough. It didn’t quite seem to stop contact between the mirror frame and the camera body. I had since found some 1.5mm black craft foam with a self-adhesive backing, so I cut some to size and attached on top of the first strip of foam. This photo makes it look less aligned than it is, and I might well re-do this at some point with two strips of the self-adhesive foam instead.

Canon FT QL mirror damper repair 4

However, it is just thick enough to effectively stop the mirror hitting the camera body both in manual and automatic actuation, but not thick enough to obstruct the light path.

Canon FT QL mirror damper repair 5

It seems to be working well in shooting so far. It is quieter – the Canon FT QL could never be described as a quiet camera, but the shutter sounds less clunky and more deliberate now.

There are still a few things I could do on this camera. As it’s got fairly high sentimental value, I’ve just bought a copy that’s in a bit of a state that I can use to practice tearing it down, and I might salvage its focusing screen to get the match circle back.


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