Vintage R-mount lens info

Posting here because it seems like the closest match, after all, apparently you can use R lenses on at least some FD cameras.

I can't seem to find much information about the R mount, or at least I can't filter it out from the noise ever since Canon reused the letter R recently.

The reason I am looking is because I bought an R lens, but the aperture blades are stuck closed. The aperture lever doesn't move. The aperture rings do, but they don't affect anything. The other pin on the back is looks bent, but not having seen another example, I'm not sure what it is supposed to look like. Here are a couple of pics:

The R lenses were not well engineered. The lens had to be cocked before it will stop down. The larger lever mates with a lever in the camera and will cock the lens when the film is advanced. The smaller lever actually trips the lens to stop down when the shutter button is pressed. Try moving the large lever, it should move and cock the lens. Then trip the smaller lever, the lens should stop down. If nothing happens, you may have lubricant on the aperture blades preventing them from stopping down. Most R lenses have two aperture rings. The rear one is the stop-down ring and, in a properly functioning lens, will move the aperture back and forth as you turn the ring. The font aperture ring is the automatic aperture ring. Once set to an aperture, that's what the lens will stop down to once the shutter button is pressed. Thankfully, Canon changed to a totally different aperture system with the FL and FD series of lenses.

Canon's first SLR was a little underdeveloped, as jim says.

 

As Camerquest (Canonflex) says:

In practical terms, you may damage your camera or lens by interchanging earlier Canonflex bodies and lenses with later FL/FD bodies and lenses. Some will be OK, some not OK, so be careful.

Interesting. Still worth playing with to see if I can loosen it up, but maybe I’ll think twice or be careful putting it on my FTb.

 

The R lenses were not well engineered. The lens had to be cocked before it will stop down. The larger lever mates with a lever in the camera and will cock the lens when the film is advanced. The smaller lever actually trips the lens to stop down when the shutter button is pressed. Try moving the large lever, it should move and cock the lens. Then trip the smaller lever, the lens should stop down. If nothing happens, you may have lubricant on the aperture blades preventing them from stopping down.

Thanks for that explanation. I played around with it a bit, and I have been able to move the larger lever. It's a bit stiff, but it will move. I think I hear something trip then when I move the smaller lever, but the larger lever doesn't return, and nothing happens with the aperture blades. It isn't that they don't stop down, it is that they are stuck at f/11 or so. don't take that aperture value as gospel, that's just me guessing. Not near as tight as you'd expect at minimum aperture, but pretty tight. Definitely not open to f/1.2

 

Most R lenses have two aperture rings. The rear one is the stop-down ring and, in a properly functioning lens, will move the aperture back and forth as you turn the ring. The font aperture ring is the automatic aperture ring. Once set to an aperture, that's what the lens will stop down to once the shutter button is pressed. Thankfully, Canon changed to a totally different aperture system with the FL and FD series of lenses.

It hadn't struck me until I read this, but this lens behaves differently from the only other two-ring lens I have used (which is an old Takumar lens). On that one, the manual ring (the one that actually moves the blades) will stop when it gets to the same stop the first ring is set at. I've assumed that this was so that you could set one ring at the aperture you wanted to shoot at, focus at full aperture, and then stop it down without having to count clicks or take your eye away from the view finder. basically, the two rings won't pass each other, and in fact you can (although I've always avoided doing it) push both using just one or the other ring. On this Canon lens, the rings pass each other without any change in feel. ++Is that the way it is supposed to be, or does that indicate something has decouplled?++

The secondary stop-down ring should move from wide-open to the smallest aperture irregardless of what the primary aperture ring is set at.

 

Your lens just needs to be taken apart and cleaned. I imagine the internals are full of dirt and dried lube. For what it's worth, R lenses aren't that hard to take apart and clean. I did so with my R 100/2.0. Or you can send out.

 

So this is the R58/1.2? A rare lens!

Yeah, the 58 1.2. Thanks for the encouragement that it isn’t too complex. Can you tell me if the angle on the smaller pin is normal, or if it got bent somehow? I think you can see it in at least one of the pictures.

Your aperture pin does seem to be on a slight angle. Not sure if it's a big deal or not, it's all part of a half-circle shaped arm that connects to the aperture mechanism. If it does cause the lens to stop down when you press it, then it works, I wouldn't worry about it.