Canon FD Maintenance - 35-105mm 3.5 Zoom Cleaning

[Zack Birlew]

Hi, everybody, does anybody happen to know where to look for a guide or knows how to take apart and clean a Canon FD 35-105mm 3.5 parfocal zoom? I've recently gotten a couple of them, the first having zoom issues that I fixed but I got another one that has fungus and dirty elements. From my work on the first one, I could see that it was a very tricky lens to disassemble and it unfortunately wasn't going to be parfocal anymore as I found that the notorious bushings failed and disintegrated. By the way, if anybody has a solution for that, I would very much like to hear about it. I can tell that the second lens feels more mechanically pristine but the fungus is ridiculous as it was sold to me as "Mint" but it was just $20 so I figure I can save it and maybe have a parfocal copy for when I need it. Still, how to get at the front glass elements seemed to be tricky and I have yet to find a video or message board that describes what to do. If nothing else, I can take what I learned on the first lens and go at the second one and see if I can get any further. Any help or advice would be greatly appreciated!

 

[Zack Birlew]

Update! I figured out how to get the front element off! Now, I don't know if it was just this particular lens, as it is dirty, but there is a thread ring on the front with spots for a lens spanner, however, don't use a lens spanner as it is installed very tightly. The thread ring is made of plastic and can easily break, I actually chipped one side of the cutouts trying to unlock it with a spanner. As it turned out, the front ring is lightly glued in place so, in my case, I used a Q-tip with some Zeiss lens cleaner, straight alcohol or alcohol-based lens cleaning solutions should work, and ran it around the ring of the front lens to let the alcohol dissolve the glue. The next part involves some firm force so the best thing to do is to take the front helical assembly off the lens. It's fairly easy, just use a toothpick or the flat end of a screw driver to gently lift up the rubber lining on the focus grip of the lens, I ran the toothpick around the lens while pulling down to slide the rubber lining down towards the zoom ring. After that, a couple of screws and a small plate should be visible with several screw holes in a line, this is for setting focus, so make any marks or note which spots the two screws are installed in and where the plate is aligned so you can redo the front assembly focus once you put the front of the lens back together. Unscrewing the screws and the plate will release the front assembly to twist all the way from the front so that you can have only the front part of the lens on its own. Now, I used a rubber lens wrench cap (look on Amazon) and twisted firmly until the front ring started moving and when that comes off, the front element is free to slide out, so don't drop it when the front thread comes out! Depending on the condition of the front element, it could also stick in its slotted position so it might need to be gently shaken out into your hand or onto a soft surface like a thick mouse pad, like I use. The second element is, as far as I can tell, locked in or glued in to the front assembly but cleaning that isn't difficult at all, again, depending on which elements are dirty, in my case the front element needing the most cleaning for fungus. I still have to get back to the lens and finish cleaning other parts but now that I know how to get to the glass from the front, the rest of the lens shouldn't be difficult based on my past experiences cleaning FD lenses.