Canon FD 50mm 3.5 Macro Stiff focus ring

<p>I need help fixing a Canon FD Macro 50mm 3.5 lens. The focus ring can become very stiff at some point such that I had to use force to turn it. I suspect that the lens barrel get gummed up inside, and try to figure out how to clean it. I do not have any information on disassembly of this lens, so I post this to ask for your advice and/or information as to what would be the best way to address this issue. The lens looks not abused, just old, so I think If I can disassemble the barrel, I can clean it so that the focus ring will turn smoothly. If this is not so, please enlighten me as to what I need to do to overcome this.</p>

<p>Thank you.</p>

<p>It may not just be a case of hardened lubricants, the lens may have been dropped or bumped distorting the helicals. There were several versions of this lens, the one with the silver ring and the nFD. I did some disassembly of both years ago, but never could totally remove all the elements....in spite of going onto this and other websites for help. So I can only wish you good luck. These are relatively inexpensive and probably much less expensive than having a repairperson work on them, so you might consider picking up another one on the big auction site and selling yours as non-working or for parts to partially offset the cost.</p>

<p>Well, what Stephen writes is true -- you can usually pick up a Canon 50/3.5 macro for $50 or so on eBay. It'll likely cost you more than that if you take it to a camera tech.</p>

<p>I've never attempted to dismantle this lens before, but I've dismantled other Canons, and lots of other lenses too. For tools, I recommend you have a set of jewelers screwdrivers and needle-nose tweezers. </p>

<p>Usually the first step to removing the focusing helical is to remove the rubber grip on the outside surface of the focusing collar. You can usually pull it off, starting at the edge, just by using a fingernail to pry up a section -- then you just keep lifting and pulling at it until you've pulled the whole grip off. If it's stubborn at first, try using needle-tipped tweezers or a jeweler's screwdriver, or something similar -- anything with a tiny point that you can insert without cutting the rubber or scarring up the collar's metal. In any case, it'lll be tight, so don't be afraid of using some force to pull it off the collar. And note for later: putting it back on usually requires less force, but you'll still have to pull at it pretty hard to get it back to where it was.</p>

<p>So after you've removed the collar, you'll see some screws, probably big ones and little ones. Actually, since this is a prime lens, you will probably see only one size screw. These screws attach the collar to the helical. Unscrew them and the collar should slide free. It's a good idea to mark the collar and helical before removal. This is one thing the needle nose tweezers is for. Scratch a small mark on a spot on the edge of the collar that won't show and scratch a similar mark on the helical, aligned with this mark, so you'll know their exact orientation when reassembling. Chances are, this probaby won't be necessary, since it's likely that there's only one way it can be reassembled. </p>

<p>So anyway, at this point, the helical might come off on its own, or there might be a screw or two acting as stops to prevent it from coming off. So you'll need to remove these stop screws as well. Rotate the helical and it will begin to unscrew from the innner helical section. You'll feel when it's close to coming loose because it will get sort of wobbly. As this happens, get ready to make some more marks. As soon as the outer helical comes free from the inner helical, bring them back together, and mark the two pieces at that exact spot with your tweezers or other sharp tool.</p>

<p>Now that you have the helical separated into its component parts, you need to disassemble no further. At this point, you want to have a good solvent for cleaning the pieces. I preferr naphtha -- it's an excellent solvent with relatively low flamability. You can find it in qt cans at the big box stores for $6-7. That 1-qt. can will last you forever. So get a toothbrush or anything similar and soak it in the naphtha and just scrub the snot out of the helical threads -- inner and outer. Once you've removed all traces of the old lubricant, dry the threads well and then relube them. I prefer molybdenum disulfide grease -- you can find it at an auto-parts store. Moly grease has excellent lubricating properties and just about zero creep at high temps. Which means it stays where you put it. Plus, it doesn't lose its lubricity over time the way the old lens lubes did. Now, you don't need a lot of this stuff. Just enough to evenly coat the threads in a very thin layer. Use the toothbrush to distribute it. Then remount the outer helical (any way, at this point it doesn't matter) and just run it from one end to the other across the inner helical. All patches of unevenness should be gone. If any remain, double check the spots on the helical where these are occurring. If there's nothing there then Stephen's caution may be a valid one. Your helical may have been bent. But I think it's also fair to say that, if it were bent, you would see then bend long before you got to this point.</p>

<p>So, assuming the helicals move smoothly, it's time to reassemble. Now comes the fun part. Fun being lining up the marks you made and hoping you lined them up correctly. This is where you'll want to slip the outer sleeve back onto the helical and align it properly so you can see if its infinity mark lines up with the one on the base of the lens. If you've managed to thread the helical at what looks like the right point, then rotate it all the way in and check to see if the sleeve's infinity mark still lines up. If it does, congratulations! If it doesn't, well, don't be too disappointed -- it's happened to me a bunch of times. So, if the marks don't line up then pay attention to two things: in which direction is the mark located (before or after the mark on the lens body), and how for away from the mark is it? This distace will give you an idea of how many threads you'll have to jump to get it back into the right thread channel. From this point forward, it's trial and error. Usually it's gonna just be one thread groove out, so concentrate on that groove next to where it was where the helicals engaged. Keep working at it. Eventually, you'll find the right channel where the collar sleeve's infinity mark lines up with the one on the lens body. When you've done this, it's just a simple matter of putting the screws back in. And restretching the rubber sleeve back over the focusing collar.</p>

<p>Hope this helps!</p>

 

<p>Thank you both Stephen and Michael.<br>

Michael, your instruction is very helpful, showing a lot of experience in dealing with these FD lenses. I certainly will not send it to any repair shop in view of cost of repair vs. cost of acquisition, but will tinker with it to see if I can make the focus ring responds more readily than it is right now.<br>

Again, zillion thanks to your advice.</p>