Olympus-OM
[Top] [All Lists]

Re: [OM] FYI: Three Zuiko Lenses plus T32 in Baltimore

Subject: Re: [OM] FYI: Three Zuiko Lenses plus T32 in Baltimore
From: HI100@xxxxxxx
Date: Sun, 25 Apr 1999 14:52:30 EDT
In a message dated 4/24/99 7:53:52 PM Pacific Daylight Time, 
tomokoy@xxxxxxxxx writes:

<< I did not think seriously of how the specs of black might affect, so I
 shot blooming flowers in my neighborhood.  The result was that I could not
 detect anything different with the 50mm/1.4 from the 4x6 prints.  Carroll 
Conway
 thinks that the black specs are paint chips from the inside walls of the 
lens.
 He suggested that perhaps if I shoot a blank white paper with the aperture 
wide
 open at close range, the specs might show up as a shadow.
 >>
Tomokoy,
               I don't think you have anything to worry about if they are 
paint chips as I remember reading an article from a photographic book from 
the turn of the century, in which they recommended painting surface bubbles 
in the glass lenses over with black paint to stop light scattering (which cut 
contrast.) Claiming the paint had no effect on lens quality.  Interestingly, 
old large lenses almost always had included bubbles.   
        Another view : just think how large a black (paint) hole the centre 
hole of a mirror lens is!    
        Probably the most likely lens/situation in which one might start to 
see an image would be with a very short focal length lens set to focus close 
so that the chips start to get within some range of being near focus. 
Depending on where the chips are relative to the diaphragm ,stopped right 
down may be worse than wide open since depth of field is greater.
        If you want to try hard to see an effect with your lens you might try 
using extension tubes and focusing close.

Tim Hughes
Hi100@xxxxxxx

< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz