Cracking open my nFD 100mm f2.8

<p>I am finally going to do it - I have nothing to lose, the lens is so cheap that repair is counterproductive as nice examples go for far less than the fee of a repairman looking at it.</p>

<p>I have to go and get some nice phillips screwdrivers, as the cheap set I have doesnt sit well in the little screws, and I don't want to butcher them.</p>

<p>The problem is aperture - its inoperative and there is a nasty grinding feel to the aperture ring.</p>

<p>I have had a very limited run of luck trying to get advice, manuals or any insight into how to do this - closest being a Rick Oleson drawing of a 50 SSC being taken apart.</p>

<p>I am not even sure if I go through the back or front, or if I have to remove the mount ring first?(I assume through the back and that I would have to...).</p>

<p>Any last minute thoughts or ideas would be great, pictures, videos, would be a miracle:) Thanks,</p>

<p>Peter</p>

<p> </p>

<p>Peter,<br>

good luck. Personally, I'd be interested in periodic reports as you work. I have a couple lenses in similar situations and haven't yet mustered the courage to open them up.<br>

Eric</p>

<p>Peter, I have been in and out of this lens successfully. I had a stuck aperture due to oil. I have some notes and pics at home that may help you. Go in the back by removing the mount. There are three (I think) screws in the flat black baffle part that has the coupling levers , DO NOT remove them unless you want to find (on the floor), clean and put about 200 steel micro balls back in with tweezers. These screws don't need to be removed to pull the mount. I'll reply again when I get home tonight.</p>

<p>Tim - THANK YOU:) I was hovering over those, wondering if to take them out or not! <br>

Eric - I will do my best to document my "progress", if nothing else it may be comic relief:)</p>

<p>With the two red dots lined up, remove 3 screws in the black plastic part where the release button in located . They are threaded into the stainless steel breech ring. Pull the breech ring out, it only goes into the lens about 1/8". Catch the lens release button.</p>

<p>The the aperture lever assembly will now come out. The lever assembly will twist clockwise from the lens mounting position because of spring tension. Make a mark where it stops for reassembly alignment reasons. Take pics and make drawings. Look inside as you pull the aperture lever assembly out and note anything that will help you line up the parts on reassembly. Pay attention to the two levers that are inside the lens and note the location for reassembly also not the location of a lug on a die cast ring that rotates when the lever assembly rotates. One sets the aperture and the other closes it down when you release the shutter. I'm sure I missed something, go slow, pics, notes, drawings.</p>

<p>Now you can determine if the problem is in the aperture lever assembly or the diaphram itself. Hopefully it is in the lever assembly or the aperture ring or a spring has broken or came loose. Lets see what you find before you have to dig deeper.</p>

<p>Oh, did I tell you that reassembly is no fun?</p>

<p>Its the diaphragm.. Its COVERED in oil. I have been working from the back, slowly, and I am here, and I am stuck:</p><div></div>

<p>So... good news/bad news time:)<br>

Good news: the diaphragm is now clean, its easy to get out... THROUGH THE FRONT...<br>

Bad new: I have a thoroughly disassembled lens that I will now attempt to put back together.<br>

Regardless, I will post my "adventure" for posterity - weather a guide or a warning is yet to be seen. </p>

<p>GOOD NEWS - its fixed. despite my most sincere efforts to make this harder than it needs to be - in a nutshell, I did about 90% more work than I had to, had I known what the hell I was doing. Even with a "diagnostic" look to see if all the levers and such were attached as they should be, this should have taken no more than 30 min.</p>

<p>You go in through the back to have a look. just remove the mount, no more. its 3 screws, that's it - do not do anything else unless you have a specific reason beyond diaphragm issues. Basically, Pic#1, 2, 3 show all you have to do back here.<br>

If, as was the case here, the levers inside the lens are all properly hooked up, and you manage to move the diaphragm, and see, as was the case with me, that it is COATED in oil, you stop there, and go to the front.<br>

On an NEW FD lens (at least on all the primes I have) there is a plastic cap that has the lens name and info on it (surrounding the front element). You pop this out one of two ways. My 100mm has a hole, a very small hole, on the barrel of the lens, just a about half an inch back of the front edge of the lens barrel (pic #4). On my 50, this is missing and all you do is pry it out from the front. </p>

<p>Once in there, there are three screws, you pop them out, then pry (gently) the little metal ring that was in there, and then you can easily remove the front group. </p>

<p>At this point you see the self contained diaphragm. Four more screws, and it can be gently persuaded to come out. Pic #5 shows how it looks.<br>

Wash with lighter fluid like I did, dry delicately, forget q-tips or anything fibrous as this will cause endless little threads of crap on your aperture blades - I started that way, then used the corner of a paper towel, basically dousing with lighter fluid, exercising the blades via the lever, then dabbing everything away, then once again, douse, exercise, dab. Once dry, go for a smoke, come back, reassemble.</p>

<p>Insert diaphragm assy. into the lens barrel, making sure it settles in there squarely.</p>

<p>According to the Oleson instructions for the old FD (SSC) 50 1.4, you reach in the back, hold the blades open via the metal lever, and tighten the screws. The only pointer I have here is to start them all then go around tightening progressively in a criss-cross pattern, as any of us who ever worked on a car will religiously and instinctively do anyway. Not sure if this is critical, but it seems to help the whole assy. settle into the barrel evenly.</p>

<p>Pop in front group, screw down the retaining ring, replace the nameplate and you're done:) Clean your fingerprints off all the shiny glass pieces and voila.</p>

<p>Have not film tested yet, but seems to function on a camera body - will run some film through it and see tomorrow. Thanks for the help everyone, I hope my experiences may be useful to someone else in this kind of fix - I assume this would be pretty much pa for the course for most nFD primes - apparently zooms are a nightmare beyond nightmares.</p>

<div></div>

<p><strong>Pic#1 </strong>shows the first part of the mount removed after three screws on the outside of the mount - this is THE SAME PLACE AS THE RELEASE BUTTON AND THE PROTRUDING RED DOT VISIBLE WHEN LENS IS MOUNTED. I just want to reiterate - NOT THE THREE SCREWS ON THE INNER BARREL - Thank you Tim, I was so about to remove those... :) DO NOT TOUCH THESE.</p>

<p><strong>Pic#2</strong> Shows the actual part with all the levers that can at this point be gently pulled out - flipped up-side-down (this is the side that goes inside the lens), where all the springs are visible. As you can see, they are in place and attached on both ends and the levers moved smoothly.</p><div></div>

<p><strong>Pic#3 </strong>is as far as you need to go - you will see two metal pieces that if nudged gently will move the diaphragm (they engage the prongs on the piece above, this should show you which ones I mean) and you will see through either front or back if the blades are oily. At this point, it seems to me that this will either be the case, or some catastrophic failure of one of the parts would be apparent - no need to go further. I am an idiot and I did... Learned a lot, scared myself sh!tless, but that's about it. For diaphragm issues, stop here:)</p>

<p>Sorry Pic#4</p>

<div></div>

<p>Pic#5 is just a demo of the removal of the name plate</p><div></div>

<p>Three more screws and the front group falls out, the four more and the diaphragm assembly - shown here, in <strong>Pic #6</strong>, is yours to play with.</p><div></div>

<p>Sorry about the crappy pics - they were taken with a phone, the only digital "camera" I own:) <br>

I went much further than I needed to - but as you can see in the first, large file attached to this thread that won't show in line - like I said, it was a learning experience...</p>

<p>As a bit of comic relief - I removed the aperture ring, and actually lost the little bit that makes it go click-click-click... Its about the size of half a flint from a Zippo lighter (a 1x1.5mm metal cylinder...). I don't know how I found it after launching it using careless screwdriver pressure and the spring under it... Don't know - luck was on my side. I would have been several times more annoyed than normal since I didn't have to go this far to get done what I needed... But I found it - I was actually going to use a flint if I didn't :) Still - its done now, will film test tomorrow.</p>

<p>Just as PS. I found this very helpful once I found it - it pertains to a n old FD lens, but it was none the less very helpful.</p>

<p>http://rick_oleson.tripod.com/index-161.html</p>

<p>The front and the mount itself comes apart differently on nFD - its actually simpler in my opinion, fewer screws...</p>

<p>Congratulations, <strong>Peter</strong>! Now you're making me feel guilty about the numerous specimens I have awaiting attention. Looks like I'd better pluck up some courage...Thanks for the useful chronicle, and pics.</p>

<blockquote>

<p>Sorry about the crappy pics - they were taken with a phone, the only digital "camera" I own:)</p>

</blockquote>

<p>I was wondering, after all your caustic posts about "photocomputers". Nice one, Peter. Hope it works for you now.</p>

<p>Congratulations Peter! Well done! I've never had the courage to attempt lens surgery myself given that I can barely replace foam seals so I'm especially appreciative of your success here.</p>

<p><strong>Rick</strong> - this was a first for me, and I was very apprehensive about it, but now I think... I might kind of... (gasp!) like doing this... who knows what I'll try next ;)</p>

<p><strong>James</strong> - caustic? nah, just calls em like I sees em ;)</p>

<p><strong>Kayam</strong> - I know how you feel - and I thought I'd messed this up, but somehow managed to just go really slow, double check and refer to my own photos and other lenses... nice thing is, that it all either fits or it doesn't, so there is not much room for error that way, as long as you remember not to force anything. Its kind of like mechanical repairs versus body work on a car I guess. Still, I have to admit - if the price of repair vs price of lens was a different ratio, I'd probably never work up the guts to do it.</p>

<p><strong>Les</strong> - I was coming up short of detailed information so I thought that I should document my efforts, be they successful or failed, that way I can share what I've learned, even if only as a cautionary tale. I have some other pictures, but mainly of the over-disassembled rear end, however if you have any questions feel free to email me or post here - I'd be happy to share whatever I learned.</p>

<p>To wrap up, thanks to all of you here and on the classic manual camera forum - you guys have been wonderful to me whenever I have had any questions, put up with my Luddite grumpiness and some of you even laugh at my jokes - those aside, I am very grateful for all your help and moral support.</p>

<p>Nice work! I've recently gotten into FD myself after years of resisting -- my father-in-law gave me an A-1 with a 50mm f/1.4 SSC that worked well but had the typical "Canon squeak" caused by dried-out lubrication in the mirror box. I liked it enough to send it out for an overhaul, from which it should return in another week or two. Your description here, combined with Rick Oleson's page, should be sufficient guidance if I ever have aperture trouble with any of my FD lenses.</p>

<p>My 100 does not have the small hole to push the name plate ring out. I had to pry from the inner part at the glass. Protected the glass so the tool would not scratch it.<br />Did the release button pop out? I don't remember for sure if mine did.</p>

<p>I have the aperture gauge sizes if you need them to test the size accuracy of the aperture opening. I didn't know to scribe the precise position of the diaphragm assembly before I took the screws out. The four screw holes are slotted for adjustment. I cleaned my diaphragm assembly by dunking in lighter fluid multiple times and moving the lever.</p>

<p>How did you get the focus helicoid back in the right thread to maintain infinity focus? I had a lot of trouble there because I didn't know to scribe it. I now know to scribe EVERYTHING. It also took many attempts to get the aperture lever assembly back in correctly.</p>

<p>I agree with you........don't disassemble any further than necessary.</p>

<p>Thanks for the detailed write up. I too have a 100 f2.8 nFD with oil soaked aperture blades. I was able to "diagnose" it by rapping on the lens a bit with the lever stopped down. The blades reluctantly closed and I could see the oil. I'll have to print these instructions so I can work on it the next time I have "free time". </p>

<p><strong>Tim</strong> - I don't think that the focusing would be an issue if you only remove as much as necessary for diaphragm - of course I did, and I ended up with a lens that focuses past infinity with a focus scale that does not match up, so in my case it was a LOT of extra work and trial and error... A bit of a cautionary tale there I guess, you're right, scribe and scribe again! This was my first attempt so I have to admit I had a lot of "oops... I guess that just came apart..." moments :) <br>

<strong>Steven</strong> - I think you'll be fine if you try to make sure you take apart only what you need to, and go very slowly, snapping lots of reference pics. Good luck, I hope you get it fixed!</p>

<p><strong>Tim</strong> - sorry, I just realized I didn't reply to your question regarding the mounting release button. Yes, once you pull the main mount, it pops out, and in my experience the only way to get it back together is to keep the button pressed when re-inserting the mount. Otherwise the mount won't sit square and the metal retaining ring (the first part to come off when disassembling the lens) will not fit in, specifically at the location of the release button. Hope this helps.</p>

<p>I literally was doing this very same thing about a month ago. I was going nuts trying to figure out how the heck to get the aperture unstuck. I took it apart countless times and could move the blades manually, but I couldn't get it to couple when mounted on the camera. I wound up having to send it to a friend and he found the oil on the blades and fixed it for me.</p>

<p>Good learning lesson though! Good luck with yours!</p>