Canon LTM the handoff took place this morning...

Canon M39 M39 screw mount bodies/lenses

back alley

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...at coffee.

bj has the canon 7 and will attempt what i am too chicken to try.
yeah, he's gonna open her up and glue that damn lg window back in.

i believe it's his first attempt with a canon but the canonator is tough and should be able to survive just fine. (we all hope)

afterwards bj is gonna do some testing with his rebuilt 135 on the longer based 7.

oh what fun.

joe
 
c'mon guys, i was kinda hoping for some words of encouragement to/for bj!

this is a truly brave & noble task he has taken on.

joe
 
backalley photo said:
c'mon guys, i was kinda hoping for some words of encouragement to/for bj!

this is a truly brave & noble task he has taken on.

joe

Good luck, bj, whoever you are ... and be careful you don't bend the ASA disc when you pull the shutter speed dial off!
 
jlw said:
Good luck, bj, whoever you are ... and be careful you don't bend the ASA disc when you pull the shutter speed dial off!
Ha, no problems there! The ASA disc has already been broken in half, so I can't do any worse. (Don't worry Joe, it was like that when you gave it to me...)

This wasn't too hard of a job: Remove the wind lever, shutter speed disc, shutter release, flash sync socket, and two screws, and lift off the top. The window had previously been glued in place with some brittle yellow stuff; I scraped it off with a knife, and re-glued the window in place with Automotive GOOP. This stuff stinks bad, but it sticks to metal and plastic like nothing, and is tougher than hell when it's dry. I cleaned the RF mirror while I was in there - free of charge!

I'll let it sit for a couple of hours so it can dry a bit more before I put it back together. All told, a one-hour job at most. And in exchange for that work, I get a week or two of use out of it. :D
 
holy crap that was fast!
i should have watched, never thought...

yeah, feel free to play, no rush.
i think miss stephanie might be the next one to play with the canonator.
;)joe
 
Goop! Be careful with Goop; it will destroy some plastics. Let it set overnight before reassembly to avoid having the fumes permeate the camera. The fumes are very unhealthy.
 
Looks like I missed a lot today. Only a few hours for the repair, very nicely done.
 
Well, this morning brings a new set of problems!

Problem #1: My 13.5 wouldn't mount on the 7, but the Nokton 50 goes on like a charm... I cleaned the threads, and after gently working it on and off a dozen times, it finally screwed down. It's still pretty tight, but there doesn't appear to be any damage to the lens or camera mount. Don't worry, it gets much more interesting!

Problem #2: Once the 13.5 is mounted, it doesn't mount "straight-up". The focus mark isn't aligned directly with the top of the mount. No biggie, 'cause it's the same with the Nokton, and also the same on my R. EXCEPT... it's just far enough off of center that the focussing tab doesn't quite meet the focussing cam, and therefore, doesn't set the rf focus accurately. I don't have the same problem with the Nokton, because the focussing tab is a full circle, not just a 0.5" tab. It looks like this lens won't work on this camera, and therefore we have a failed experiment.

Problem #3: The RF alignment is out. After #1 and #2, I mounted the 50 and just did a quick sanity check. The close focus distances seem to be fine, but the infinity focus is off. Using the 50, and comparing to the R, there's definitely a problem. I have the instructions to adjust this correctly, so I'll go through that process today (or if I run out of time, this week sometime).

So... I'll adjust the RF, and make sure that everything is working, and looks like you'll be getting her back next weekend. I'll run a quick roll through with the 50 if I have a chance, to make sure that everything is kosher. On the plus side, that little window is still firmly in place. I wouldn't recommend putting your finger in it again, though. :p

Anybody wanna send me an M3 for testing this 13.5cm lens? :D I'll take good care of her, I promise!
 
how disappointing!

it's odd how some lenses screw right on and others not at all.
maybe the pitch is different.

sorry bj, all that work for nought.

joe
 
Hey, no problem! Not that much work really, and now I have an excuse to keep asking for someone to loan me an M3. :D I'm not holding out for miracles, though.

I've fixed the RF alignment; it was out a little at infinity, but seems to be pretty good at close distances. This week I'll blow a short roll through with my 75, and that'll help make sure everything is good.
 
BJ Bignell said:
Problem #2: Once the 13.5 is mounted, it doesn't mount "straight-up". The focus mark isn't aligned directly with the top of the mount.

Seems as if Canon lenses never do -- they always wind up with the focus index pointed toward the lower inside corner of the VF window, not right on top. This is so consistent among all my Canon bodies and lenses that I'm convinced Canon did it on purpose, to make it easier to check the focus distance when the camera is held up near your eye.

EXCEPT... it's just far enough off of center that the focussing tab doesn't quite meet the focussing cam, and therefore, doesn't set the rf focus accurately. I don't have the same problem with the Nokton, because the focussing tab is a full circle, not just a 0.5" tab. It looks like this lens won't work on this camera, and therefore we have a failed experiment.

Okay, that IS a biggie. Any chance that the lens has its flange mis-indexed vs. the optical section? I just looked at the most "sanitary" screwmount Canon tele lens I have (100mm f/2, very clean, never taken apart) and on this lens the coupling tab is offset from the focusing index by about 40 degrees clockwise as seen from the rear. I don't know what 13.5cm lens you're using, so don't know whether there's any way to assemble the flange in some other position, but that could be what happened. Worth checking before giving up, anyway.

Problem #3: The RF alignment is out. After #1 and #2, I mounted the 50 and just did a quick sanity check. The close focus distances seem to be fine, but the infinity focus is off. Using the 50, and comparing to the R, there's definitely a problem. I have the instructions to adjust this correctly, so I'll go through that process today (or if I run out of time, this week sometime).

If you've got a metric depth gauge or dial indicator, you might want to check the lens(es) first just to make sure. With any screwmount lens, regardless of focal length, when the focus distance is set to infinity, the surface of the coupling cam or tab should be 7.50 mm above the face of the lens' mounting flange; at 1 meter the cam should be 4.60 mm above the flange.

It's difficult to measure this super-accurately unless you have a jig or stand that lets you keep the depth gauge absolutely perpendicular to the surfaces, so if you're just measuring by hand don't be surprised if you're off by a few hundredths of a mm... but if it's much more than that, suspect problems with the assembly of the lens rather than with the rangefinder!

(I know you probably already knew these measurements, but thought I'd quote them anyway in case anyone else doesn't. Just measuring the cam "stick-out" directly is a lot more positive than the method I used to use of saying, "Well, I think this lens is OK and it seems to couple all right on this camera body, so if this other lens also couples OK on this body but not on that body, then the problem must be in the lens, unless that body has a problem..."

Dial indicators and other measuring instruments are pretty inexpensive to buy online nowadays, if you don't mind getting a slightly cheesy imported one, and I've become convinced that one of them is a very useful accessory for anybody who has accumulated a lot of strange old lenses and needs a quick way to check whether or not they might be munged up!)​
 
jlw,

Any lens I mount on the 7 seems to point towards the vf (I don't have any Canon lenses handy, though). Such is the case with the 13.5cm lens; it's an Arco Colinar f=13.5cm/3.8. They also do this on my R, but not as much; they're more upright.

The coupling tab on this lens is directly in line with the focussing mark on the barrel. There's only one place for the tab, and there's not much else I can do about it. In fact, this entire lens can only be assembled one way, or it's very obvious that something is wrong. You can read my teardown in the link I provided above; I welcome any comments you can offer if you see I've done something wrong.

The face of the tab is about 1.9cm across, and when it's screwed onto the 7 with the flange tight against the mount, the focussing cam on the body is resting on one of the shoulders of the tab, not on the face. It's close, but no cigar. You can see a picture of the tab below. This isn't a problem with the 50mm Nokton, or the 75mm Color-Heliar, as they both have a full-circle focussing tab (see second picture).

I didn't know the measurements you quoted, wrt to the flange-to-tab distance. Those will be very handy in the future, I'm sure. Thanks! I checked the 13.5 and my 50 with an ordinary plastic ruler, and the read the same. I know through use that the 50 is accurate.

I checked the RF using my 75 and some wax paper in place of film. When the lens was focussed very far away on a building, the dual images in the range finder didn't meet. I've adjusted this to my satisfaction (which hopefully means "correctly"). Close-up distances checked with a standard tape measure also pass muster. I've started a roll of film in the camera now, and we'll see if the rf is setup correctly when I'm done.


Victor: Yes, GOOP is nasty stuff, but I found that it worked really well without damaging the window. I've used it on standard automotive plastics as well, without concern. Doesn't work worth a damn on shoes, though. I suppose that's why they make shoe GOOP a separate product. :rolleyes:

I believe the person who said "Canon lenses on Canon bodies" was a guy named Victor M. ;) Seems to be pretty sound advice...
 
VictorM. said:
Who was it that said "Canon lenses on Canon bodies"?


this was for the sake of science & optical experimentation.
plus it really wasn't me doing it and i never saw a thing.

it's not like i think the body will catch a 'dark' disease from the lens or anything.

it's very hard to explain a neurosis...

joe
 
Odd ! My Canon 7 also presents resistance to accept some LTM lenses and you need to 'insist' a bit, mainly with FSU ones. This also goes against it's BORG assimilating nature...

Ops, Brian is coming !
 
After noticing the tripod screw of my 135/4.5 Hektor didn't quite sit level when the lens was mounted, I discovered three screws (carefully disguised as vulcanite) that when loosened allow the entire lens to rotate on the camera. After reading the recent comments on this thread, I checked and found that the focus cam rotates into the correct position at the same time. The screws are at the very rear of the focus mount. Maybe the Arco has similar screws.
 
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