Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Jun 26, 2005, 12:37 PM   #1
Rui
Junior Member
 
Join Date: May 2005
Posts: 12
Default

I recently received a lens i got off of ebay in the mail. Unfortunitly the lens seems to have a defect that the owner was unaware about.

It's a pattern of white dots that spreads over a few centimeters.

http://i-rui.com/dots on 85mm.jpg

I took a couple of test shots and can't see anything on the images itself, but my main concern would be if it's something serious that will worsen with time.

Also, I'm curious about how much something like this devalues the lens (since I was told it was optically perfect).

Any idea of what this is??
Attached Images
 
Rui is offline   Reply With Quote
Sponsored Links
Old Jun 26, 2005, 12:42 PM   #2
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

Take a good look at the anti-reflective coating on the lens. If that is a macro shot it could be in focus. There are also coatings between lens elements in a good lens, so you might not be able to see it. If it is on your macro photos and blurred or not visible on longer shots I would have to guess the coating isn't perfect.
slipe is offline   Reply With Quote
Old Jun 26, 2005, 1:55 PM   #3
Rui
Junior Member
 
Join Date: May 2005
Posts: 12
Default

It IS a macro shot of the lens. I'm not sure a standard lens would be able to show the dots.

The defect appears to be on the INSIDE of the front element. It is only visible when the light hits it at a certain angle.

The pattern only appears on a small area of the lens - not over the entire surface (so i don't think it's the coating)
Rui is offline   Reply With Quote
Old Jun 26, 2005, 9:48 PM   #4
Senior Member
 
Join Date: Jan 2004
Posts: 824
Default

Rui wrote:
Quote:
The defect appears to be on the INSIDE of the front element. It is only visible when the light hits it at a certain angle.

The pattern only appears on a small area of the lens - not over the entire surface (so i don't think it's the coating)
Without being able to see more of the lens up close, I'd guess it is mold growing on the coating of one of the inner lens surfaces. It is not unusual in humid climates; I had a couple of enlarger lenses that got mold in them due to the humid state of my darkroom here in Japan. There's nothing really you can do about it; offhand I'd guess that sending the lens in for repair would cost more than buying a new lens. Depending on how bad the mold is, it will probably result in some degree of softening (lower contrast) in the image.

Norm in Fujino is offline   Reply With Quote
Old Jun 27, 2005, 12:27 AM   #5
Rui
Junior Member
 
Join Date: May 2005
Posts: 12
Default

I brought it to a camera shop to get a salesmans advice - he thought it was probably something wrong with the coating. Although he did say there is a CHANCE it COULD be mold in early stages (there's no spidering on teh pattern) He suggested i bring it to minolta for their oppinion and perhaps a cleaning if necesary.

Just from the test shots I took I'd like to keep the lens - it's a nice 85mm F/1.4. Although i'm thinking i probably deserve some kind of componsation in return (15% money back?)
I live in canada (so does the ebay seller) - but our summers do get quite humid, and it was rather hot the day it was deleivered to me....so that could've been a factor.
Any other advice / opinions?

I'll update when i know more.
Rui is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 7:15 AM.