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Re: [PanoToolsNG] Re: Sigma 8mm f3.5 Fisheye for Canon EF mount.... out of focus?

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  • Wolfgang Lin
    Yes Hans, this is what I am going to do. I was thinking that it should give me AF result on the 1 meter (b coz when I use the Canon 15mm, the camera AF could
    Message 1 of 12 , Dec 30, 2009
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      Yes Hans, this is what I am going to do. I was thinking that it should
      give me AF result on the 1 meter (b'coz when I use the Canon 15mm,
      the camera AF could give me a clear result). Now for this Sigma 8mm,
      the camera AF result is not on the 1 meter position but the infinity,
      and thus it is not clear.

      Wolf


      2009/12/30, Hans <hans@...>:
      >
      >
      > --- In PanoToolsNG@yahoogroups.com, Wolfgang Lin <wolfgang.lin@...> wrote:
      >>
      >> Hi everybody,
      >> Tested several times on different subjects: different F-stops,
      >> focal distances, and camera settings, I found the root cause!
      >>
      >> The trouble is a very typical Sigma lens trouble, which I
      >> original do not expect to meet on a fisheye lens, that it is simply
      >> b'coz of "focal point shifted"! Using the function on 5D2 to adjust
      >> the shifting to "forward +20", I get a better result but still out of
      >> focus!
      >
      > ??? What are you talking about. What shifting?
      >
      > There is no such function and anyway what would you use it for.
      > An 8mm should not be used with autofocus unless you want to work in the
      > 0.2-0.5 meter area.
      >
      > There is no idea in that.
      > Set the focus at 1 meter. That gives you focus from 0.5m to infinity even at
      > full aperture. Thats it. Disable the autofocus and put a large peace of
      > ducktape to lock the focus so that you do not change it by mistake.
      >
      >
      > Hans
      >
      >
      >
      >>
      >> What a good Sigma! My friend's another 3.5 fisheye has the trouble!
      >>
      >> Wolf
      >>
      >> 2009/12/30, dburton97128 <dburton97128@...>:
      >> > The Sigma f4 looks sharper than the Canon in that example. Is that
      >> > expected?
      >> >
      >> > David B
      >> >
      >> > --- In PanoToolsNG@yahoogroups.com, "Hans" <hans@> wrote:
      >> >>
      >> >> Re: Sigma 8mm f3.5 Fisheye for Canon EF mount.... out of focus?
      >> >>
      >> >>
      >> >>
      >> >> --- In PanoToolsNG@yahoogroups.com, "jrgen_schrader" <panorama@> wrote:
      >> >> >
      >> >> > The Canon 15mm is definitely a reference for websized panoramas and a
      >> >> > circular
      >> >> >fisheye will hardly ever beat it. But to judge your individual case we
      >> >> > would
      >> >> >need a sample
      >> >> >picture or 100% crops of center and edges.
      >> >>
      >> >> Here is a test comparing the centre of the Canon 15mm with the old
      >> >> Sigma
      >> >> 8mm f4.
      >> >> To make them comparable the images are taken at distances that give you
      >> >> the same
      >> >> size of the subject. Image in 100%
      >> >>
      >> >> http://www.panoramas.dk/panorama/sigma8/Sigma8-Canon15.jpg
      >> >>
      >> >> Taken with Canon 5D Mark II
      >> >>
      >> >> Hans
      >> >>
      >> >>
      >> >
      >> >
      >>
      >
      >
      >
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