canon fd manual lens question

chriscurl

chriscurl

Well-known member
ok, so i got a canon fd 28mm manual lens (my first one) to use with my sgblade, but im not sure if I'm stupid or if this thing is broken (possibly both), as I can't get the aperture control to work.

When I have the lens connected to its mount, the aperture lever on the back will slide back and forth and close the aperture down, and it will only go as far as the dial lets it, so that is right, but I can find no way to get it to stay at any aperture besides wide open, what am I not doing to get it to stay at a certain aperture?

Maybe there is some hidden switch I am missing?
 
http://www.redrockmicro.com/forum/v...&start=0&sid=7ab223e25561d05186d765af320983bf

FD_QTip.jpg
 
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Also, here's a little known trick: the older breechlock FD lenses (the ones with the silver ring instead of the release button) have a "built in Q-tip"! Simply press the bigger of the two levers counterclockwise like is shown in that Q-tip picture... and press a little harder, and it will click into place! No Q-tip required. It will also click back out of that mode if you want to use it on an SLR again. You can tell they do this because they have a much longer slot for the lever to move in.

All FD lenses, of course, won't actuate their apertures while dismounted from a camera. So once you lock that lever in position through either method you have to mount it up on an SLR or adapter to then see the aperture ring have a result.

Duncan
 
One thing I don't understand is why 35mm manufacturers don't just design their FD mount so that you don't have to modify FD lenses. As far as I know only Letus have done this and it's extremely useful. I used to have to modify my lenses and have the q-tips pop out on set etc.
 
To have a mount work like you want with Canon FD lenses, it would have to include some kind of lever in it that you would move *after* the lens is mounted. Is that what Letus did?

You actually don't have to modify the lenses. In the case of the older breechlock lenses, the lever clicking into place gives you the manual aperture, and is there for precisely that reason. (To work with the older FL-mount cameras that didn't have auto-apertures.) So the simplest thing to do is just buy the breechlock versions of FD lenses. In almost every case that's an option, only in the case of a couple of lenses is it not. (The 14/2.8 rectlinear wide angle being the most interesting.) Even the much-touted "L" lenses almost always have a breechlock equivalent, though the older designation was usually "Aspherical" and they can be hard to track down (but still generally cheaper than the L ones!)

If you have the later bayonet-style lenses and don't like Q-tips, there is an official Canon part that performs this function and won't fall out like Q-tips can. When I'm home in a couple of days I can post a picture of it. They only sold for a dollar or so originally (it's just a piece of plastic) but they are no longer made and hard to find, but not impossible.

I just did a google image search and found someone else's picture of the piece. It's the tiny one on the right:

http://static.photo.net/attachments/bboard/00B/00BM19-22151584.jpg

That still doesn't quite show how it works, so I'll post pictures next week.

Duncan
 
frobozz said:
To have a mount work like you want with Canon FD lenses, it would have to include some kind of lever in it that you would move *after* the lens is mounted. Is that what Letus did?
Click to expand...

The Letus mount has a groove in it that catches the lever once the lens is locked in place. The result is that FD lens behaves like any other once they're on the mount. Very useful. I don't like the breech lock design so much because you have to give it an extra twist to secure it versus just screwing it on.
 
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