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Canon FD recommendations
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PostPosted: Mon Jun 19, 2017 12:07 am    Post subject: Reply with quote
stevemark wrote:
They are prone to wear-and-tear, especially those primes that include zoom-like focusing threads (sorry, i don't know the proper term in English).

Are you talking about single-helicoid focusing systems?


PostPosted: Mon Jun 19, 2017 11:58 am    Post subject: Reply with quote
Gerald wrote:
stevemark wrote:
They are prone to wear-and-tear, especially those primes that include zoom-like focusing threads (sorry, i don't know the proper term in English).

Are you talking about single-helicoid focusing systems?


This is exactly what led me to build Minolta lens range. I did buy a Canon nFD 24mm f 2.8 (for about 50-60£) early on and found it mechanically so unsatisfactory (plasticky, some play), especially compared to the Minolta lenses I previously owned that, rightly or wrongly, I never looked back. A pity as it seems they are often optically equivalent or superior, offer more choice and usually cheaper.


PostPosted: Tue Jun 20, 2017 11:06 am    Post subject: Reply with quote
Gerald wrote:
stevemark wrote:
They are prone to wear-and-tear, especially those primes that include zoom-like focusing threads (sorry, i don't know the proper term in English).

Are you talking about single-helicoid focusing systems?


Single helicoid "new FD" primes have just one problem - the internal (rotating) mechanism of the bayonet.
Primes with floating elements or primes with internal focusing have an additional (and more serious) problem:
their internal focusing mechanism contains sliding bearings (?? not shure whether this is the correct English term!).
These are coated with an unknown synthetic material which is prone to disintegration.


IMAGES FROM http://www.digicamclub.de/showthread.php?t=16843

It seems this (now defective) material was mainly used in the Canons high quality lenses, and not in the cheap MF zooms.
My oldest lens with such a problem is an (otherwise pristine) FD 2.8/300mm Fluorite.

Repairing is usually quite cumbersome, since one has to replace the defective bearings with new, specially made parts.

Stephan


PostPosted: Tue Jun 20, 2017 11:17 am    Post subject: Reply with quote
Antoine wrote:
Gerald wrote:
stevemark wrote:
They are prone to wear-and-tear, especially those primes that include zoom-like focusing threads (sorry, i don't know the proper term in English).

Are you talking about single-helicoid focusing systems?


This is exactly what led me to build Minolta lens range.
...


Yep, that's why i have collected mainly Minolta MC and MD-I lenses. Their focusing is extremely smooth and silky. Obviously there's no play at all, and everything is made of metal. Most of these lenses have brass-on-aluminium focusing threads. The combination of brass and aluminium is ideal, but heavy (Leitz was using the same combination). Later Minolta changed to (lighter) alu-on-alu focusing threads, and they are quite a bit harder to use, especially if we have double focusing threads (MD 2.8/200mm) or floating focusing (MD 2.8/20mm, MD-III 2.8/24mm, MD-III 2/28mm). If we compare the ame generation of lenses, the Minoltas are usually as good as the corresponding Canon FD lenses. But, of course, Minolta didn't offer those precious special lenses that Canon had ...

Stephan


PostPosted: Tue Jun 20, 2017 8:14 pm    Post subject: Reply with quote
stevemark wrote:

Single helicoid "new FD" primes have just one problem - the internal (rotating) mechanism of the bayonet.
Primes with floating elements or primes with internal focusing have an additional (and more serious) problem:
their internal focusing mechanism contains sliding bearings (?? not shure whether this is the correct English term!).
These are coated with an unknown synthetic material which is prone to disintegration.


A better term for these pieces would probably be "bushing" rather than bearing.

I have run across bushings such as these in a couple of Vivitar S1 lenses I've dismantled. But they used teflon rather than that black stuff. They held up well to the effects of wear.

If you had access to a micro lathe you could probably make some -- perhaps out of solid brass? Brass has self-lubricating properties. I dunno though -- those sharp angles may present a problem.

I have been told that Canon's IF lenses require special tools to work on the IF components. I was warned not to mess with the IF on mine because without these tools I'd never get things set right again.


PostPosted: Tue Jun 20, 2017 9:44 pm    Post subject: Reply with quote
I buy and sell quite a lot of gear, but the 55mm 1.2 Asph with the Speedbooster Ultra combo will always be a part of my kit. That lens is pure magic on my Fuji cameras.


PostPosted: Tue Jun 20, 2017 9:45 pm    Post subject: Reply with quote
cooltouch wrote:
stevemark wrote:

Single helicoid "new FD" primes have just one problem - the internal (rotating) mechanism of the bayonet.
Primes with floating elements or primes with internal focusing have an additional (and more serious) problem:
their internal focusing mechanism contains sliding bearings (?? not shure whether this is the correct English term!).
These are coated with an unknown synthetic material which is prone to disintegration.


A better term for these pieces would probably be "bushing" rather than bearing.



I think a very common denomination is guide roller. In professional lenses, these rollers were made of brass. In consumer lenses, it was common to use a material called Delrin. Then Canon decided to innovate ... In the 1990s, many of those "revolutionary" rubber compounds turned out to be a disaster. Canon had two prosumer camcorder, L1 and L2, whose handles were coated with a rubbery layer that turned a glue after a few years. And the infamous Sigma's Zen coating is cursed to this day.


PostPosted: Wed Jun 21, 2017 6:03 am    Post subject: Reply with quote
Gerald wrote:
Then Canon decided to innovate ... In the 1990s, many of those "revolutionary" rubber compounds turned out to be a disaster. Canon had two prosumer camcorder, L1 and L2, whose handles were coated with a rubbery layer that turned a glue after a few years. And the infamous Sigma's Zen coating is cursed to this day.


Probably the same stuff used on some Nikon cameras e.g. Nikon F90X


PostPosted: Sun Jun 25, 2017 6:52 pm    Post subject: Reply with quote
Gerald wrote:
cooltouch wrote:

A better term for these pieces would probably be "bushing" rather than bearing.


I think a very common denomination is guide roller.


Thanks for correcting me!!

In fact, Teflon would have been quite OK - Canons cheaper zooms from that time seem to use Teflon, and they don't have these problems.
Teflon can be a problem if very tight tolerances are to be met. I know that Minolta Switzerland did offer a service to change the Teflon guide rollers of the Minolta AF 1.4/85mm to brass ones, on request, and for a substantial amount of money ...

Stephan
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