| Author |
Message |
    
Thuggins
Tinkerer
Username: Thuggins
Post Number: 2
Registered: 12-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 30, 2007 - 05:56 pm: | 
|
I have a Pen 38mm, f1.8 lens that is focusing past infinity. The focus seems shifted across the entire range, so that the focus scale always shows less than the actual distance.
It appears that the focus ring has just slipped out of position on the helicoid. Is this adjustable? The focus ring seems tight and moves smoothly, so I don't know how it would have slipped.
There are three very, very, very small screws set at about 120 degrees going thru the focus ring. They appear to be set screws. I'm a bit reluctant to mess with them without knowing for certain what they do. I did take the front and back elements out for cleaning, but the lens reassembled without any problems. So I am doubting this caused the problem.
Has anyone had experience adjusting the focus on this (or any SLR) lens? I've never seen a focus ring slip without it being really loose. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 472
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, December 30, 2007 - 08:51 pm: |
|
My notes on the 38/1.8 only deal with cleaning the diaphragm and don't show the focus ring. However, it is common for the ring to be attached with screws or set screws that could slip and cause exactly what you're seeing. I don't know if the set screws you're looking at are the ones that would have caused it in this lens. |
Thuggins
Tinkerer
Username: Thuggins
Post Number: 3
Registered: 12-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 08:47 am: |
|
Hey Rick, thanks for the response. Can you direct me to the notes you mention? You never know when you might run across one of those "Ah-ha" moments! |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 473
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, December 31, 2007 - 09:31 am: |
|
they're not online; if you email me at [email protected] i'll send you what i have. |
Thuggins
Tinkerer
Username: Thuggins
Post Number: 4
Registered: 12-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 01, 2008 - 11:18 pm: |
|
The three set screws in the focus ring were the fix for the problem. These lock the focus ring to the helicoid. At some point these must have loosened, and whoever tightened them got the focus ring off position. These just needed to be loosened a bit, the focus ring positioned correctly, and the set screws retightened. |
