Canon 100mm f/3.5 needs repair

[traveler_101]

Hi,

I have a black and silver striped version,and it takes very good photographs when I can get it in focus, which for close portrait shots wide open can be difficult. The lens does not sit on the camera properly --the top of the lens is actually a few degrees to the left of centre; the aperture ring is too loose. I have unscrewed the bottom of the lens from the helicoid without removing any screws--that can't be right.

Is there any way for me to repair the lens? Where might it be sent for repair and what would it cost?

 

[kuuan]

Hi,

actually it sounds as if your lens is alright!
- the distance scale to be to the left of the center is a feature of Canon rangefinder lenses to see the selected aperture inside ( some ) rangefinders.
- the mount and helicoid separating from the optical block incl aperture assembly is normal for Canon RF tele lenses. If you take these two parts apart it should be easy to adjust tightness of aperture:
- see my instructions on how to adjust tightness of aperture, actually to loosen it so that focus doesn't get off-set when turning the aperture ring, on the 1.8/85, scroll quite far down this forum page: http://forum.mflenses.com/7-canon-rangefinder-lenses-t66636,start,30.html ( will verify later if the sample applies to the black / chrome 3.5/100 )
..and btw. you are lucky that your lens doesn't have a milky inner element which is a very common problem with a many early Canon RF lenses and which hardly, if at all, can be repaired

see e.g. the distance scale offset to abt. 2 o'clock position of my 1.8/35 on Canon P

Edit: is the aperture clickless? I just verified that on mine it is, and it's running quite loosely too ( both of which I prefer: the Canon LTM teles have a single helicoid which turns, unless the aperture ring is very loose, the focus ring when setting aperture. that makes focusing wide open and stopping down thereafter, which I usually do when using on mirrorless, impossible )
It doesn't have the same mechanism as most Canon LTM teles, incl. the 1.8/85, as shown in the link provided earlier, do. Sorry, can't help you to make it more tight.

 

[traveler_101]

Hi,

Just noticed your edit. Yes, my lens lacks click stops and it is very loose; it didn't seem as if that could have been according to manufacturing standards, but it works. I had managed to get off the aperture ring cover -- a previous owner and put glue over the screws -- only to discover that the optical assembly looks nothing like the 85mm you had posted on a different forum; specifically there is no leaf spring assembly. So now I will simply reassemble.

Ok, not too difficult . . . . it is put back together. It is excellent glass and is capable of sharp photographs, but I have trouble getting it into focus at 3.5. I might post later with a photo of the helicoid assembly. Perhaps there is something wrong there.

Thank you very much for your help. Much appreciated.

 

[kuuan]

see here: http://www.rangefinderforum.com/forums/showthread.php?t=50647
there various users report that their chrome / black 3.5/100 also have clickless aperture ( and, as my feeling also has been, that in this tiny lens there isn't room for a clickstop assembly similar to the other Canon LTM teles )
When I had checked my copy to see for it's aperture assembly I had tried to take of the 'aperture ring cover' but it's tiny screw also seems to have glue on top and the screw wouldn't bulge, as I feel there is nothing wrong with my lens of course I just left it

again, it seems to me that your lens is just as it should be, there is nothing that should or could be repaired.

may I ask which camera you are using for focusing? I use mine on NEX5n and Ricoh GXR M, that is digital cameras and for focusing I use enlargement + focus peaking ( the former being the more important aid, the later being more reliable on the Ricoh, in return the higher res. EVF on the Sony let's me simply see what is in focus better and I don't have to rely on it's less precise focus peaking ).
I have not found this lens particularly difficult to focus, but relatively speaking yes because generally focus peaking won't work as well with old manual lens that have rather weak contrast.

 

[traveler_101]

see here: http://www.rangefinderforum.com/forums/showthread.php?t=50647
there various users report that their chrome / black 3.5/100 also have clickless aperture ( and, as my feeling also has been, that in this tiny lens there isn't room for a clickstop assembly similar to the other Canon LTM teles )
When I had checked my copy to see for it's aperture assembly I had tried to take of the 'aperture ring cover' but it's tiny screw also seems to have glue on top and the screw wouldn't bulge, as I feel there is nothing wrong with my lens of course I just left it

again, it seems to me that your lens is just as it should be, there is nothing that should or could be repaired.

may I ask which camera you are using for focusing? I use mine on NEX5n and Ricoh GXR M, that is digital cameras and for focusing I use enlargement + focus peaking ( the former being the more important aid, the later being more reliable on the Ricoh, in return the higher res. EVF on the Sony let's me simply see what is in focus better and I don't have to rely on it's less precise focus peaking ).
I have not found this lens particularly difficult to focus, but relatively speaking yes because generally focus peaking won't work as well with old manual lens that have rather weak contrast.

Thank you very much for taking the time to help. I use my example on film cameras. I have had more luck with the Leica IIIf than the Bessa T--both have magnified old style rangefinders.

When you mention digital, I occurred to me that it may be a good idea to try it on digital and see how it does. I have Olympus m43 and I have a m39 to m43 adapter so I can check it out and see what I have. I'll post again when I can. Thanks.