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Tim_witt
Tinkerer
Username: Tim_witt
Post Number: 3
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 06, 2008 - 10:24 pm: | 
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This is the first lense I have disassembled. I have been careful, taking notes and making sketches. I disassembled this lense to wash the oil off the aperture assembly and to clean and grease the focus assembly. I should have marked or made note of how far the outer helicoid is screwed into the lower part of the lens hub. These are ultra fine threads. You can screw the outer helicoid into the lens hub until it bottoms out.
I wish I knew the proper terminology for lense parts, maybe this would not sound so amateurish.
On the inner helicoid, what is the purpose of the small black square of material in the slot between the two guide slots that keep the inner helicoid from rotating when focusing? It feels like rubber. Maybe to provide some resistance to focus ring rotation?
How do you determine how far to screw the outer helicoid into the lower part of the lense hub? The focus ring is not attached and the inner helicoid is not inserted.
After the inner helicoid is inserted, how do you determine where to lock down the focus ring? |
Tim_witt
Tinkerer
Username: Tim_witt
Post Number: 5
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 10, 2008 - 10:33 pm: |
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Not enough notes or sketches, the aperture will not open fully (almost) even with rotating the aperture unit in the oblong mounting holes.
I think I have the questions in my first post solved.
The lens didn't cost much, just right for a learning project but I'm at a dead end now.
Does anyone have a manual for this lens? Canon FD 100mm f2.8 new type breech ring. |
Glenn
Tinkerer
Username: Glenn
Post Number: 273
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 11, 2008 - 02:57 pm: |
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Canon did not produce a manual for individual lenses in the nFD range. There is a parts list complete with exploded diagram for each lens. Then there are service notes for the various ranges of lenses, ie - wideangles, standard lenses, short teles, long teles and the zooms are split into three ranges depending on zoom ratio. The standard lens service notes contain details of iris adjustment and mount service, plus other general repair details. So for a particular lens you may need two or three different parts, especially if you are not well versed in that lens.
From memory the 100/2.8 is nothing out of the ordinary, so does not have many, if any notes on assembly, ie it depends on the general notes.
I am sorry that I cannot help you further, but without actually seeing what you are doing, I cannot tell what you are doing wrong - if anything. |
Donnie_strickland
Tinkerer
Username: Donnie_strickland
Post Number: 42
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 12, 2008 - 10:46 am: |
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Rick Oleson has some FD lens notes here:
http://rick_oleson.tripod.com/index-161.html
Rick might be along shortly; he might have more on this... |
Tim_witt
Tinkerer
Username: Tim_witt
Post Number: 6
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 12, 2008 - 04:52 pm: |
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My last post says new type breech ring, it should read new type bayonet mount. Optically it it is the same as the breech type of which I have one.
I set the depth of the inner helicoid into the lens body so the measurement of the back side of rear element to front side of front element matches the good lens (2.212 inches+/-). Then I put the lens on a split prism body and focused on a distant subject. I locked the screws on the focus ring at infinity then and rechecked focus.
Rick's sketch of the 50mm breech ring lens differs from the new FD but does have some similarities. I have been taking photos and making sketches of this 100mm which should be similar to most new FD lenses down to at least 24mm. I'm also writing a basic instruction sheet on what not to take the screws out of and what to scribe or mark for location as well as other handy info.
To complete this lens, I need the aperture diameter measurements for each stop.
I know you set the aperture unit at one stop and it should be close at all stops but I still want to know how close they all are. |
Glenn
Tinkerer
Username: Glenn
Post Number: 275
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 12, 2008 - 05:24 pm: |
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Tim,
I will dig out the manuals tomorrow - recently moved house and they are in a box in loft - I think I have all the aperture dimension tables, but do know that some of the individual lens tables do not list all aperture diameters. Still 3 or 4 are better than 1! |
Glenn
Tinkerer
Username: Glenn
Post Number: 277
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 13, 2008 - 05:34 pm: |
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Tim,
Sorry, do not have the nFD 100/2.8 dimensions. I have a full set of breech lock data, but for the nFD series I only collected data for the lenses I had/used. Hence the data I have is for the nFD 100/f2.
You need sections 2.3 and 2.4 of the nFD Repair Manual - General Comments/Instructions. The problem is that I have never seen this part of the manual offered for sale complete. All sellers just seem to offer various parts of this manual attached to the various parts lists. This state of affairs appears to stem from the fact, that the source photocopy was assembled by somebody who did not understand the original Canon microfiche sequence. Even OTC here in the UK (who are great to deal with and have original manuals as source material), seem to have trouble just providing this section of the manual. Even from this firm's comprehensive index of Canon manuals, it is not possible to pick out this section easily. It gets rather expensive trying to buy the correct sections - I tried, and still did not get all I wanted! |
Tim_witt
Tinkerer
Username: Tim_witt
Post Number: 7
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 13, 2008 - 10:45 pm: |
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Glenn,
According to information from Canon and other sources, the nFD 100mm f2.8 has the same optics as the breech lock version. The minimum aperture on the nFD is f32 and the breech lock is f22. If this is true, wouldn't the breech lock aperture data be the same other than f32? |
Glenn
Tinkerer
Username: Glenn
Post Number: 280
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 14, 2008 - 10:50 am: |
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Tim,
Yes, two versions of this lens are optically the same. Will send the data directly to you, via email, this coming weekend. Have to dig the manual out again! |
Glenn
Tinkerer
Username: Glenn
Post Number: 281
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 15, 2008 - 03:42 pm: |
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Tim,
Well here are the figures, all in mm. Because there is not a uniform +/- tolerance over the f range, I will give the diam range for each stop.
f2.8... --.--20.38 --.--
f4.. 15.61 14.26 13.08
f5.6 10.97 10.05. 9.21
f8.... 7.72.. 7.08.. 6.49
f11... 5.44.. 4.99.. 4.57
f16... 3.84.. 3.52.. 3.23
f22... 2.71.. 2.48.. 2.28
So you have a fair leeway over actual measured diameters. Iris blades must not be visible at maximum aperture. Canon state to set the aperture at either f8 or f11 and the measure the diameters of various f numbers - measure diameter obtained by both stopping down from max and opening up from min. This procedure will take care of any back-lash in the mechanism.
If you read the complete nFD lens repair manual, it soon becomes apparent that setting up the lens to give accurate exposures with the AE system is very critical. Thus we can repair these lenses, but very rarely do we get the original factory AE limits back. Problem usually shows itself when one sets up a lens right on an edge of tolerance band, when mounting this lens on different bodies, you get slightly different readings. Mind you the film latitude usually comes to our rescue. |
Tim_witt
Tinkerer
Username: Tim_witt
Post Number: 8
Registered: 02-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 17, 2008 - 07:44 pm: |
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Glenn,
I have the aperture set within the limits using drill bits within the range as go-no-go gauges. Checked f5.6 to f22 going up and down, there is minimum or no backlash. Bit set is too small for f4 or f2.8 but f2.8 does open completely.
The lens is functioning properly.
I learned a lot from this first lens disassembly/reassembly. Take notes, make sketches, scribe locator marks, disassemble only what is necessary and don't clean a clean lens.
Triple the above comments.
Thanks for your help. |
