"fixing" stuck aperture blades, Canon FD 100 2.8

[TomWB]

I got this lens with a bunch of other fd lenses in an as-is state. This lens appears new except the aperture blades won't move. I've tried on various bodies, T-90, F-1, EF, and there is no movement when stopping down or shooting manual or automatic....The aperture setting ring will move, and it will also move to the A setting for T-90, etc. I've compared the mount side of the lens with other lenses that do work, and they all appear the "same" in regards to position of aperture clicker thingey, etc.

Anyone ever taken one of these apart, or have any ideas what the problem could be? As I said the lens appears new, there is no junk visible in the lens at all. I have the usual small screwdriver set and a spanner wrench i use for LF lenses. I've searched here and photo.net, and net, couldnt find anything. Found plenty of service manuals for free for FD bodies, but no free ones for lenses. BTW, I don't care if i destroy the lens, I've got plenty of others, but it would be nice if it did work.

 

[David A. Goldfarb]

Could be oil on the aperture blades.

If you decide to try to fix it, start from the mount end, go slowly, and take pictures as you go. It can be tricky to get the aperture control levers connected again once you've taken them apart.

 

[GregT.]

Yep, probably oil on the aperture blades. Very good lens otherwise, but for some reason its prone to oil settling on the aperture blades.

When it happens to me, I put the lens on one of my F1s, rotate the Aperture Ring to f:/32 and then depress the Multi-Function Lever as if manually stopping down to check depth of field. I repeat this a number of times in succession and eventually the blades respond by opening and closing as they should. Maybe not a permanent fix, but worth a try.

Taking the lens apart myself is a sure prescription for screwing it up permanently (too many thumbs.) One of these days I'll have to look into the cost of cleaning and adjusting. In the meantime, I exercise the aperture blades frequently as I described above.

 

[TomWB]

Yep, probably oil on the aperture blades. Very good lens otherwise, but for some reason its prone to oil settling on the aperture blades.

When it happens to me, I put the lens on one of my F1s, rotate the Aperture Ring to f:/32 and then depress the Multi-Function Lever as if manually stopping down to check depth of field. I repeat this a number of times in succession and eventually the blades respond by opening and closing as they should. Maybe not a permanent fix, but worth a try.

Taking the lens apart myself is a sure prescription for screwing it up permanently (too many thumbs.) One of these days I'll have to look into the cost of cleaning and adjusting. In the meantime, I exercise the aperture blades frequently as I described above.

Thank you both for the response. I tried the stop down lever on my EF through half of Law and Order last night, without any results. I then took the lens off and slammed it into my palm several times, and the aperture released itself, however, would only stay at f-32, even when set on 5.6, etc, and would only do it temporarily, but slamming on palm would again release it. I notice there is a lot of oil in there, so will be taking it apart, following David's advice. Incidentally, I recently "fixed" a T-90 with the "frozen" shutter problem by slamming it on my palm, now it gets a weekly shutter workout. I credit Mark Wahlster on photo.net for giving me this tip. Thanks

 

[Mike Kennedy]

Try applying lighter fluid on Q-tip ends. Lightly dip the QT in a bottle cap worth of lighter fluid or naptha and EVEN SOFTER dab the shutter blades.
Use a bulb air blower to dry. Repeat/repeat/repeat.........and keep working the aperture button.
Anything that might cure a shutter blade problem without dismantling the lens is your best course of action.
This has worked for me for 7 out of 10 misfunctioning lenses.

Good Luck,
Mike

 

[TomWB]

Try applying lighter fluid on Q-tip ends. Lightly dip the QT in a bottle cap worth of lighter fluid or naptha and EVEN SOFTER dab the shutter blades.
Use a bulb air blower to dry. Repeat/repeat/repeat.........and keep working the aperture button.
Anything that might cure a shutter blade problem without dismantling the lens is your best course of action.
This has worked for me for 7 out of 10 misfunctioning lenses.

Good Luck,
Mike

Mike, thanks, but on this lens I think the aperture blades are between lens elements? Are you referring to a large format lens that screw apart to mount on lensboard? Am I off base? thanks

 

[Mike Kennedy]

What was I thinking? My mind must still focused on our election (Canadian)
If you can find a repair manual on line that would be perfect.
Getting to the blades could be a problem unless you are familiar with this lens.
You might try to work a little lighter fluid through the aperture slide or button on the lens bottom. Just a dab on a Q-tip then work the blades. That might work. I fixed a Pentacon lens like that. Took a few days.

Good Luck,
Mike

 

[GregT.]

I notice there is a lot of oil in there, so will be taking it apart, following David's advice.

You might find reviewing this diagram useful before jumping in...granted its for a 50mm f:/1.4 but should give you at least an idea of what to expect:
http://rick_oleson.tripod.com/index-161.html

Good luck.

EDIT: The drawing is from Rick Oleson's Tech Notes Page at http://rick_oleson.tripod.com/index-27.html

 

[shadesofgrey]

Try applying lighter fluid on Q-tip ends. Lightly dip the QT in a bottle cap worth of lighter fluid or naptha and EVEN SOFTER dab the shutter blades.
Use a bulb air blower to dry. Repeat/repeat/repeat.........and keep working the aperture button.
Anything that might cure a shutter blade problem without dismantling the lens is your best course of action.
This has worked for me for 7 out of 10 misfunctioning lenses.

Good Luck,
Mike

Hi Greg. The above works, do it all the time when I buy a 'Junker'. Working on a Jupiter 8 and spare 24-48 S1 as we speak. Your particular lens is not that hard to dismantle (reading from Rick's page) just do as Mike says and take lots of pics (Digi of course) and make lots of notes. If the galss is as you say then the lens is worth the hassle. Once you've done this lens you can progress to a Lomo Cosmic Symbol. You think I jest? Wait till you take the leaf apart! Take care.
B.

 

[rhphoto]

If you can find a can of aerosol de-gunker, that stuff is so volatile, it evaporates immediately, leaving no trace. But it will unfreeze aperture blades. I did this with a large format lens, and the blades were totally accessible. Don't know about your SLR lens. But the propellant might shoot inside and do the trick. As far as I know, it won't hurt anything, as it's so pure.

 

[TomWB]

You might find reviewing this diagram useful before jumping in...granted its for a 50mm f:/1.4 but should give you at least an idea of what to expect:
http://rick_oleson.tripod.com/index-161.html

Good luck.

EDIT: The drawing is from Rick Oleson's Tech Notes Page at http://rick_oleson.tripod.com/index-27.html

Greg, those links are a gold mine. Don't know why I didn't find them, I've found free pdfs of service manuals for T90, etc. but none for lenses. Thanks again. Tom in Seattle

 

[Mike Kennedy]

WARNING: Be prepared to create your very own paper weight!!!!!

Been there,done that, and more than once.

Good Luck,
Mike

 

[GregT.]

Tom,

I'm guessing you're already familiar with Christian Rollinger's Canon FD Documentation Project. If not, click on "enter" at the bottom of the page at Dead Link Removed.

Greg in Gig Harbor

 

[TomWB]

Tom,

I'm guessing you're already familiar with Christian Rollinger's Canon FD Documentation Project. If not, click on "enter" at the bottom of the page at Dead Link Removed.

Greg in Gig Harbor

Yes. Greg, are you documenting the construction of the new Narrows Bridge? Dynamic changes when I go down there a couple times a year...

 

[GregT.]

...are you documenting the construction of the new Narrows Bridge?...

Yes, in 4X5; how far my project goes remains to be seen. Several pixelographers appear to have the same goal in mind.

Greg