Olympus-OM
[Top] [All Lists]

Re: [OM] Generic lenses for Oly OM equipment

Subject: Re: [OM] Generic lenses for Oly OM equipment
From: Richard Schätzl <Richard.Schaetzl@xxxxxxxxxxxxxxxxxxxx>
Date: Tue, 24 Feb 1998 14:01:16 +0100
Kennedy wrote:
 
> The diffraction limited cut-off frequency of a lens is given by
>                  Wo = 1/(L * f/#)
>       where Wo is the cut-off frequency in cy/mm at the focal plane
>       and   L is the wavelength in mm
> 
> Thus, for an f/32, the cut-off frequency of the diffraction limited
> optic is 62.5cy/mm at the focal plane, assuming a mean wavelegth for
> visible light of 600nm.
> 
> This is independent of focus distance, magnification or whether there is
> an 'r' in the month.  :-)

Independent of Magnification so far only for the "real or effective
aperture", because the effective aperture (in contrary to the choosen
aperture on the aperture ring) will get smaller with higher
magnification.

For example: choosen aperture = 5,6 effective aperture at 1:1 = 11
  
Richard


############################################################
| This message was delivered via the Olympus Mailing List
| To receive the Digest version mailto:listserv@xxxxxxxxxxxxxxx
|    with "subscribe olympus-digest" in the message body.
| To unsubscribe from the current list mailto:listserv@xxxxxxxxxxxxxxx
|    with "unsubscribe olympus" in the body.
| 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