| Author |
Message |
    
Thamnophis
Tinkerer
Username: Thamnophis
Post Number: 7
Registered: 03-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 10, 2013 - 11:27 am: | 
|
I started to take this lens apart to get at some fungus - removed the rear 2 lenses. But I'm not sure if I should continue.
Can I get to the front lens elements this way?
I can not get the front lens off.
 |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 109
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 10, 2013 - 01:59 pm: |
|
This is an FD lens. Right? I've never worked on one of these before, but I suspect there will be more elements between your current position and the front element. I could be wrong of course, I'm just guessing based on past experiences. You're at the diaphragm and this is a wide retrofocus.
So, why can't you go in from the front? Perhaps a specialized tool is in order? Keep in mind, "specialized" is not necessarily "expensive". Anyway, need to know the issue with front entry first. |
Thamnophis
Tinkerer
Username: Thamnophis
Post Number: 8
Registered: 03-2013
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 10, 2013 - 02:43 pm: |
|
Thanks for the input. I tried to unscrew the front with a rubber thing normally used under a table leg. Its the right size and gets a fairly good grip, but can't get it to loosen the plastic ring holding the lens on.
There are no notches to get a lens wrench into. |
Glenn
Tinkerer
Username: Glenn
Post Number: 1065
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 11, 2013 - 10:43 am: |
|
Which lens is this? If it is the cheap version of the 24mm, the front ring is stuck on with a couple of dabs of contact adhesive. If this is case make a thin 'L' shaped lever to go between ring and front element. Protect element with folded lens cloth, insert short leg of tool into gap between element and ring and gently lever ring away from element.
To check for glued ring, you can push a piece of thin paper right down between filter threads and outer edge of ring if glue is used.
If screwed ring, run a small amount of naphtha into the threads before trying the rubber ring again.
Also note that front group is accessed from the front of the lens. |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 110
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 11, 2013 - 01:24 pm: |
|
Excellent advice from Glenn.
I hate glued rings. I much prefer it when things just unscrew politely.
In the case of adhesive, I've tried to send a little solvent (e.g. acetone or alcohol) down into the correct area to loosen/disolve the glue. On lenses, this always worries me. I hate to get anything liquid into areas I don't want it.
Anyway, that piece of paper Glenn mentioned can act as a conduit to wick solvent into glued areas. Doesn't take much, and better to go slowly and add smaller amounts than rush things and gush.
Good luck! I've never had a Canon 24mm, but it's a useful focal length. I didn't know Canon made a "cheap" version of anything wider than 28. One of the Canon wides I'm very much on the lookout for is the FL version of their 19mm. The older and smaller version (non retro-focus). Its a good performer and I can use it on my SLR bodies or on my rangefinders (with adapter). |
Glenn
Tinkerer
Username: Glenn
Post Number: 1067
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 12, 2013 - 11:07 am: |
|
Jeff,
Yes the FL lens is a useful tool. I was somewhat surprised to find out about a glued ring on the 24mm FD. However my informant knew his stuff and sent images of ring showing no threads. I did wonder at the time if somebody had filed them off because the ring got cockled and would not screw in. Seen that a couple of times on other makers lenses |
