Olympus-OM
[Top] [All Lists]

[OM] Re: Sigma 12mm f/8 fisheye

Subject: [OM] Re: Sigma 12mm f/8 fisheye
From: "John A. Lind" <jlind@xxxxxxxxxxx>
Date: Wed, 08 Mar 2000 12:46:31 +0000
At 15:27 3/8/00 , Robin M. Allen wrote:
>I've seen a Sigma, 12mm, f8 fisheye for OM second hand (USD280).  I tried it
>out on a body in the shop and it produced a round image with about 150f
>the top and bottom cut off leaving black curving edges at the sides.  The
>horizontal angle of view seemed to be about 150 degrees.
>
>I wondered whether that was what is expected as I've only ever seen full
>frame or round image fisheye lenses and the max aperture size seems to be
>unusually small.  It's not listed on the Sigma web site.  Is it a one off?

It is an older Sigma lens (not current).  The current Sigma fisheyes are
8mm f/4 and a 15mm f/?.  For a full image circle on the 35mm film plane
(180 degree Vertical and Horizontal FOV), the focal length needs to be
about 7.5mm.  Full circle fisheyes for 35mm format are typically rated 7mm
or 8mm focal length.  The other popular fisheye focal length is 15mm or
16mm which gives 180 degree FOV across the diagonal in the film plane.  A
16mm fills the rectangle with the diameter of the image circle being the
same as the diagonal.  The 12mm you found is between these two.  Some
cutoff in the vertical direction is to be expected with the curved sides.

-- John

< 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>
  • [no subject], Robin M Allen
    • [OM] Re: Sigma 12mm f/8 fisheye, John A. Lind <=
Sponsored by Tako
Impressum | Datenschutz