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aizan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 17, 2006 - 07:13 pm: | 
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the aperture signal lever is off on a 100/2.8 lens. how do you adjust it? i see three screws holding the cover ring in place. do i remove this to get at the adjustment, and how is it done? |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 12:29 pm: |
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There is no adjustment to the signal levers on FD lenses. Do not remove the three screws, which I have a suspicion, you are referring to. Which type of FD lens is this, new FD or breech ring? It is possible to see two sets of three screws on the new FD and one set on the breech ring. I mean very easily visible, when I state this.
The only three screws that you should remove on the new FD are the ones in the lock ring, that hold the stainless steel bayonet ring in place. Remove the ones in the rear mount proper, and you will have 97 steel balls rolling about!
From memory, the balls in the breech ring lens do become free when you fully strip the lens mount.
However what are you saying your problem actually is? That the lens gives the wrong exposure compared with other lenses? By this I mean really off and not just +/- one stop.
You correct this by setting the iris to a set of predetermined diameters. You can do this by removing the front cell and resetting the iris. Do this by slackening off the adjustment screws and moving the iris unit, as a whole.
If you let me know the type of FD lens, I can give you the calibration diameters - you insert a metal rod of the required diameter into the iris and gently close the blades onto the rod. If you do this for 3 or 4 f stop positions, you get a well calibrated aperture. |
aizan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 01:18 pm: |
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eek, thanks for the warning! I was about to open it up.
the lens is new fd. in the viewfinder, it shows f4 when the aperture ring is f2.8. the blades are fully retracted at this point. exposure doesn't seem to be affected.
so there is no adjustment to the signal lever? why isn't the right aperture indicated in the viewfinder? |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 18, 2006 - 08:13 pm: |
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Right: so I now understand problem, but cannot pinpoint without your answers to following:-
I am assuming that it is only this lens that behaves like this - Correct? ie It could be camera fault, but you will have checked this.
With camera on manual and shutter set to B. Open the back and point rear of camera at light source. Now look through front of lens and manually stop down. Make sure you actually see the iris close down, each time you move the aperture ring.
When I have the answers to the above, I will see if we can sort it out. It is 03.00 hrs and I am going to bed! Will be back later today. |
aizan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 19, 2006 - 03:40 pm: |
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yeah, it's the only lens that does it.
i was in the middle of a roll when i noticed the problem, and i didn't think to look from the back. you know how you can nudge the aperture ring a little bit past wide open? you have to do that to completely open the aperture. they move in a little when it's just at f2.8. aside from that, the iris does close down when i move the aperture ring.
thanks for all your help. i didn't see that from the front. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 19, 2006 - 07:21 pm: |
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Aizan,
Is this lens new to you or have you had it for some time, the fault just appearing? Should have asked this before, only came to me as I was building up a FD 24mm/f1.4L that needed a new actuator ring.
What I said about there being no actual adjustment on the mount levers is correct. However the actual cam on the actuator ring is adjustable - within limits, if you replace the actuator ring or cam you have to set up the new parts according to the spec diagram.
So you have two possibilities; if lens is new to you it has been taken apart and assembled with mismatched parts, or if you have had it a long time the actuator ring/cam have worn or cam has moved.
Good news is that it is easy to bring lens back to spec if ring and cam are not the original parts, or if wear is not too bad. You only need to remove the rear mount and if it is this, the calibration of the iris diameter will not be needed.
I think the best thing is for you to email me directly with your full name and address, I will post you a copy of the relevant bits of the new FD set up procedures. There are various diagrams etc and you will find it much easier to do this way.(I only have a couple of dedicated film scanners, so am unable to scan A4 manuals).
Glenn |
aizan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 20, 2006 - 02:06 am: |
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it's fairly new to me, though i'm not sure if it was always like this or not.
i'll send you an email now. =) |
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