Pentax 17-28 versus Sigma 15mm Fisheye

Discussion in 'Pentax' started by Paul, Sep 30, 2003.

  1. Paul

    Paul Guest

    I currently have some Pentax and some Nikon, and am considering going to all
    Nikon. One thing in the Pentax line that I really like is their 17-28. The
    closest thing to that owning Nikon and no Pentax would be the Sigma 15mm
    fisheye. So, has anyone used both, and is the Nikon comparable to the Pentax
    at the wide end in degree of distortion and angle of coverage?

    Thanks,

    Paul
     
    Paul, Sep 30, 2003
    #1
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  2. Paul

    Bhup Guest

    Umm I have tried the sigma fish eye.. BUT a fisheye is a totally different
    concept to a normal 17-28mm lens.. these lens have corrections for
    distortion. I owna Nikkor 16mmAFD Fisheye and as the sigma lens distortion
    is the name of the game in fisheye lens.. the only staight line is ones that
    pass through the centre of the frame... The Sigma looked similar looking
    throgh the viewfinder to the nikkor..16mmfisheye.. but I'm pleased with the
    nikkor.. as i know just looking through the viewfinder is NOT a measure of
    how good a lens is.. you need to have results on paper or look under a
    microscope at the negs
    Going back to the orignial question.. you cannot compare a 17-28 with a
    fisheye!!!!! they are not the same

    B
     
    Bhup, Sep 30, 2003
    #2
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  3. Paul

    T P Guest


    You're wrong, Bhup. The Pentax 17-28mm is a zoom fisheye.

    ;-)
     
    T P, Sep 30, 2003
    #3
  4. Paul

    Paul Guest

    Going back to the orignial question.. you cannot compare a 17-28 with a
    You have probably never looked through a Pentax 17-28 - it is not flat, nor is
    it meant to be.
     
    Paul, Sep 30, 2003
    #4
  5. Paul

    Paul Guest

    You're wrong, Bhup. The Pentax 17-28mm is a zoom fisheye.
    Thank you!

    So back to the original question - is the Sigma 15 fish comparable to the
    Pentax 17-28 at the wide end?
     
    Paul, Sep 30, 2003
    #5
  6. Paul

    Bhup Guest

    Thanks T.P I did not know that .. thats the beauty of a newsgroup..
    I know you are pentax expert where as I am not .. I made a huge asumptin
    that there is no such thing as a Zoom fisheye

    Dohh....
     
    Bhup, Sep 30, 2003
    #6
  7. Paul

    Bhup Guest

    Paul you are correct I have nevre looked through a pentax 17-28 zoom
    fisheye
    hope someone can answer the orginal question

    I have eaten enough humble pie. I feel sick is there anymore pie ?

    B
     
    Bhup, Sep 30, 2003
    #7
  8. Paul

    Mark Roberts Guest

    You'll find a lot of comments on this lens here:
    http://www.concentric.net/~Smhalpin/LongComments.html#17-28 mm f/ 3.5-4.5 AF

    Apparently it's almost rectilinear at the 28mm lens and shows increasing
    field curvature as you approach 17mm, so it's possible to dial in the
    amount of fisheye effect you want.

    I'm not a fisheye fan myself so I've never tried it. Those who have seem
    to enjoy using it.
     
    Mark Roberts, Sep 30, 2003
    #8
  9. Paul

    Mark Roberts Guest

    Mark Roberts, Sep 30, 2003
    #9
  10. Paul

    T P Guest

    Thanks for calling me an "expert" - however my knowledge of Pentax
    gear is a long way short of that.

    I found out about the Pentax zoom fisheye when I was lambasting the
    optics Cosina 19-35mm zoom lens ... that lens had such massive
    distortion that I called it something like "the world's first zoom
    fisheye", only to find that Pentax had beaten them to it!

    ;-)
     
    T P, Sep 30, 2003
    #10
  11. Paul

    Paul Guest

    ,,,Paul you are correct I have nevre looked ,,,through a pentax 17-28
    zoom,fisheye
    ,,,hope someone can answer the orginal ,,,question

    ,,,I have eaten enough humble pie. I feel ,,,sick is there anymore pie ?


    No sweat. I've done the same myself, so there isn't a hell of a lot I can say
    about the whole thing!

    Take care.

    Paul
     
    Paul, Oct 1, 2003
    #11
  12. Paul

    Bill Tuthill Guest

    LOL. T P you are funny.

    But is the Pentax 17-28 more fisheye than the Cosina 19-35 rectilinear[sic] ?
    I've always wanted a zoom fisheye; maybe I can find a Cosina.

    In this essay, Bob Atkins proves that a fisheye becomes a rectilinear lens
    on a DLSR with cropping factor:

    http://www.photo.net/equipment/canon/10D/
     
    Bill Tuthill, Oct 1, 2003
    #12
  13. Paul

    T P Guest


    Two comments:

    1) I am not sure that the words "rectilinear" and "Cosina" should be
    used in the same sentence unless a negative modifier is present,

    and

    2) The Pentax zoom fisheye is a genuine fisheye throughout its zoom
    range, obviously with a reduction in rectilinear distortion as it
    approaches the longer (28mm) end.

    With its massive barrel distortion, the Cosina zoom acts almost like a
    fisheye at 19mm but has almost as much pincushion distortion at 35mm
    as it has barrel at 19mm. It is not a lens for the discerning
    photographer - it requires of its user either complete ignorance of
    optics, a sense of humour, or preferably both.

    ;-)
     
    T P, Oct 2, 2003
    #13
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