Distortion fix formula/workflow for Tokina 12-24 AT-X Pro f/4?

Discussion in 'Digital Photography' started by k-man, Apr 28, 2006.

  1. k-man

    k-man Guest

    Hi:

    I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    given the price. It's got some noticeable distortion, though,
    particularly at the wide end. Anyone with any experience with this
    lens care to share a workflow or Photoshop (I'm using CS at the moment)
    formula that they've used or are using to help correct the distortion?
    I've done a few by hand and it's not too terribly painful. But with
    working with a lot of images of course any help is most welcome.

    Thanks!
    Kevin
     
    k-man, Apr 28, 2006
    #1
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  2. k-man

    frederick Guest

    k-man wrote:
    > Hi:
    >
    > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    > given the price. It's got some noticeable distortion, though,
    > particularly at the wide end. Anyone with any experience with this
    > lens care to share a workflow or Photoshop (I'm using CS at the moment)
    > formula that they've used or are using to help correct the distortion?
    > I've done a few by hand and it's not too terribly painful. But with
    > working with a lot of images of course any help is most welcome.
    >
    > Thanks!
    > Kevin
    >

    http://epaperpress.com/ptlens/
     
    frederick, Apr 28, 2006
    #2
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  3. k-man

    k-man Guest

    > k-man wrote:
    > > Hi:

    >
    > > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    > > given the price. It's got some noticeable distortion, though,
    > > particularly at the wide end. Anyone with any experience with this lens
    > > care to share a workflow or Photoshop (I'm using CS at the moment)
    > > formula that they've used or are using to help correct the distortion?
    > > I've done a few by hand and it's not too terribly painful. But with
    > > working with a lot of images of course any help is most welcome.

    >
    >
    > > Thanks!
    > > Kevin

    >
    >
    >
    > http://epaperpress.com/ptlens/
    >


    Looks pretty slick. The Tokina's not in the database. But it looks
    like I can submit photos for generating calibration and correction
    values. Good tool.

    Thanks.
    Kevin
     
    k-man, Apr 29, 2006
    #3
  4. k-man

    2 Guest

    k-man wrote:

    > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    > given the price. It's got some noticeable distortion, though,


    Gawd, that's horrible distortion. Even the fix leaves the contents (see the
    lamps) skewed.
     
    2, Apr 29, 2006
    #4
  5. k-man

    k-man Guest


    >
    > k-man wrote:
    >
    >
    > > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially >

    > given the price. It's got some noticeable distortion, though,
    >
    > Gawd, that's horrible distortion. Even the fix leaves the contents (see
    > the lamps) skewed.
    >
    >


    I assume you're talking about the lamps in the PTLens "demo" pic.
    Yeah, pretty bad. Only the center is really usable (to me anyway).
    Fortunately, my pics don't start out anywhere near that distorted. I
    tried the plug-in version on a test Nikon 12-24 pic I had taken and, at
    least for that pic, PTLens seemed to work OK.
     
    k-man, Apr 29, 2006
    #5
  6. k-man

    Guest

    2 wrote:

    > Gawd, that's horrible distortion. Even the fix leaves the contents (see the
    > lamps) skewed.


    Assuming you're talking about the sample photo at
    http://epaperpress.com/ptlens/
    with the bikes in front of a wall, the original image appears
    to be a section out of a fisheye image - both horizontal and
    vertical lines are very curved. The corrected image is
    rectilinear. The lamps look oval because objects at
    the edge of a wide angle rectilinear image are stretched.
    It is not a failing of the lens nor program, it's inherent
    to rectilinear wide angle images. This is why, if you use
    an extreme rectilinear wide angle to take a picture of a
    group, the people at the edge will have egg-shaped heads.
    (Well, will _look_ like they have egg-shaped heads.)

    The original fisheye image makes the lamps look more
    spherical, but straight lines running across large sections
    of the image are obviously curved. You can't make a single
    projection that works over wide areas, makes straight
    lines straight, and preserves area/shape. It's the same
    problem that makes it hard to represent the globe on
    a flat map.
     
    , Apr 29, 2006
    #6
  7. k-man

    frederick Guest

    k-man wrote:
    >>k-man wrote:
    >>
    >>>Hi:

    >>
    >>>I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    >>>given the price. It's got some noticeable distortion, though,
    >>>particularly at the wide end. Anyone with any experience with this lens
    >>>care to share a workflow or Photoshop (I'm using CS at the moment)
    >>>formula that they've used or are using to help correct the distortion?
    >>>I've done a few by hand and it's not too terribly painful. But with
    >>>working with a lot of images of course any help is most welcome.

    >>
    >>
    >>>Thanks!
    >>>Kevin

    >>
    >>
    >>
    >>http://epaperpress.com/ptlens/
    >>

    >
    >
    > Looks pretty slick. The Tokina's not in the database. But it looks
    > like I can submit photos for generating calibration and correction
    > values. Good tool.
    >
    > Thanks.
    > Kevin
    >

    The Tokina 12-24 is in the database, but maybe not against the dslr
    model that you are using. It is there for Nikon, but I don't see it for
    Canon. If you tell PTlens that you are using a Nikon, then it should be
    very close - although the sensor size is different. (strikes me as kind
    of odd, because I couldn't lay my hands on a Tokina with Nikon mount,
    but the Canon mount ones seem reasonably readily available).
    What PTLens is *exceptional* for is easy correction of more complex
    distortion patterns, such as the "moustache" pattern seen on many of
    these newer small sensor ultra w/a zooms, and wide/telephoto (17 or 18
    to xx or xxx) zooms at the wide end.
    Another interesting use for it, is to load an image of a grid pattern at
    3:2 ratio, then see what all the lenses you might have ever wanted to
    own are really like for distortion (assuming that the PTlens databse is
    correct - which it seems to be for the lenses that I own). You see it
    in "reverse" once "corrected" of course, but there are a few surprises
    there. Distortion on some coveted (but older design) w/a prime lenses
    is sometimes quite bad, and some of these newer zooms are very good.
     
    frederick, Apr 29, 2006
    #7
  8. k-man

    2 Guest

    "k-man" <> wrote in message
    news:...
    >
    >>
    >> k-man wrote:
    >>
    >>
    >> > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    >> >

    >> given the price. It's got some noticeable distortion, though,
    >>
    >> Gawd, that's horrible distortion. Even the fix leaves the contents (see
    >> the lamps) skewed.
    >>
    >>

    >
    > I assume you're talking about the lamps in the PTLens "demo" pic.
    > Yeah, pretty bad. Only the center is really usable (to me anyway).
    > Fortunately, my pics don't start out anywhere near that distorted. I
    > tried the plug-in version on a test Nikon 12-24 pic I had taken and, at
    > least for that pic, PTLens seemed to work OK.
    >
     
    2, Apr 29, 2006
    #8
  9. k-man

    2 Guest

    <> wrote in message
    news:...

    > It is not a failing of the lens nor program, it's inherent
    > to rectilinear wide angle images.


    It is inherent to a cheap, compromise designed "rectilinear" lens. That is
    one crummy lens.
     
    2, Apr 29, 2006
    #9
  10. k-man

    2 Guest

    "frederick" <> wrote in message
    news:1146299354.641509@ftpsrv1...

    > [.,..] Distortion on some coveted (but older design) w/a prime lenses is
    > sometimes quite bad, and some of these newer zooms are very good.


    What OLD so-called w/a "prime lens" is coveted and still as bad as that? Who
    would covet a lens that performs like that?

    The zoomie in question is abysmal by any standard.

    If you want outstanding w/a lenses, you have to go back to those that worked
    without a mirror between the rear of the lens and the film or sensor. You
    are doomed in the DSLR game.
     
    2, Apr 29, 2006
    #10
  11. k-man

    k-man Guest


    > The Tokina 12-24 is in the database, but maybe not against the dslr
    > model that you are using. It is there for Nikon, but I don't see it for
    > Canon. If you tell PTlens that you are using a Nikon, then it should be
    > very close - although the sensor size is different. (strikes me as kind of
    > odd, because I couldn't lay my hands on a Tokina with Nikon mount, but the
    > Canon mount ones seem reasonably readily available). What PTLens is
    > *exceptional* for is easy correction of more complex distortion patterns,
    > such as the "moustache" pattern seen on many of these newer small sensor
    > ultra w/a zooms, and wide/telephoto (17 or 18 to xx or xxx) zooms at the
    > wide end. Another interesting use for it, is to load an image of a grid
    > pattern at 3:2 ratio, then see what all the lenses you might have ever
    > wanted to own are really like for distortion (assuming that the PTlens
    > databse is correct - which it seems to be for the lenses that I own). You
    > see it in "reverse" once "corrected" of course, but there are a few
    > surprises there. Distortion on some coveted (but older design) w/a prime
    > lenses is sometimes quite bad, and some of these newer zooms are very
    > good.
    >


    Yep, the Tokina *is* in the database. Strange, I can't figure out why
    I didn't see it in there last night and I chose Nikon D70s. Maybe I
    had more beers than I thought. :)

    Thanks again for your help!

    Kevin
     
    k-man, Apr 29, 2006
    #11
  12. k-man

    k-man Guest


    > >>k-man wrote:

    >
    > >>>Hi:

    >
    >
    > >>>I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    > >>>given the price. It's got some noticeable distortion, though,
    > >>>particularly at the wide end. Anyone with any experience with this
    > >>>lens care to share a workflow or Photoshop (I'm using CS at the moment)
    > >>> formula that they've used or are using to help correct the distortion?
    > >>> I've done a few by hand and it's not too terribly painful. But with
    > >>>working with a lot of images of course any help is most welcome.

    >
    >
    > >>>Thanks!
    > >>>Kevin

    >
    >
    > >>http://epaperpress.com/ptlens/

    >
    >
    > > Looks pretty slick. The Tokina's not in the database. But it looks
    > > like I can submit photos for generating calibration and correction
    > > values. Good tool.

    >
    >
    > > Thanks.
    > > Kevin

    >
    >
    >
    > The Tokina 12-24 is in the database, but maybe not against the dslr
    > model that you are using. It is there for Nikon, but I don't see it for
    > Canon. If you tell PTlens that you are using a Nikon, then it should be
    > very close - although the sensor size is different. (strikes me as kind of
    > odd, because I couldn't lay my hands on a Tokina with Nikon mount, but the
    > Canon mount ones seem reasonably readily available). What PTLens is
    > *exceptional* for is easy correction of more complex distortion patterns,
    > such as the "moustache" pattern seen on many of these newer small sensor
    > ultra w/a zooms, and wide/telephoto (17 or 18 to xx or xxx) zooms at the
    > wide end. Another interesting use for it, is to load an image of a grid
    > pattern at 3:2 ratio, then see what all the lenses you might have ever
    > wanted to own are really like for distortion (assuming that the PTlens
    > databse is correct - which it seems to be for the lenses that I own). You
    > see it in "reverse" once "corrected" of course, but there are a few
    > surprises there. Distortion on some coveted (but older design) w/a prime
    > lenses is sometimes quite bad, and some of these newer zooms are very
    > good.
    >


    Yep, the Tokina *is* in the database. Strange, I can't figure out why
    I didn't see it last night, not even for my Nikon D70s. I must have
    had more beers than I thought. :)

    Thanks again for your help.

    Kevin
     
    k-man, Apr 29, 2006
    #12
  13. k-man

    Go-dot Guest

    On Sat, 29 Apr 2006 08:15:45 -0500, "2" <> wrote:

    ><> wrote in message
    >news:...
    >
    >> It is not a failing of the lens nor program, it's inherent
    >> to rectilinear wide angle images.

    >
    >It is inherent to a cheap, compromise designed "rectilinear" lens. That is
    >one crummy lens.
    >

    This clown, aka "2", has no idea what he is talking about. One should
    just ignore his ignorant ravings. He's obviously clueless about
    photography and optics.

    The "distortion" being discussed is indeed normal for true projection
    (i.e. straight lines in reallity remain so in the image). When using a
    flat image plane (i.e. film and/or current CMOS/CCD sensors) you have
    a choice of either straight lines and "distorted" heads or curved
    lines and "normal" heads. (You can't change the laws of physics,
    captain!) Such "distortion" is more properly referred to as wide angle
    persepective.

    One potential solution would be the use of a digital sensor with a
    spherical, rather than flat surface (think of the retina in one's
    eye).

    However, the use of such a sensore would be limited to wide angle use
    as it would present servre problems to normal/telephoto lenses unless
    the curvature of the sensor could be made to vary as the focal length
    of the lens in use. Also, the manufacturing of such a device is well
    beyond current capabilities.

    I use PTLens (mentioned elsewhere); the current version of the
    database includes the Tokina 12-24 for the Canon 350D - both of which
    I own and use. PTLens is easily corrects the slight barrel distortion
    produced by the Tokina.

    Nothing can "correct" the wide angle distortion you are referring to
    without inducing a significant fisheye effect.
     
    Go-dot, Apr 29, 2006
    #13
  14. k-man

    Paul J Gans Guest

    k-man <> wrote:
    >> k-man wrote:
    >> > Hi:

    >>
    >> > I recently bought a Tokina 12-24 AT-X Pro f/4. Nice lens, especially
    >> > given the price. It's got some noticeable distortion, though,
    >> > particularly at the wide end. Anyone with any experience with this lens
    >> > care to share a workflow or Photoshop (I'm using CS at the moment)
    >> > formula that they've used or are using to help correct the distortion?
    >> > I've done a few by hand and it's not too terribly painful. But with
    >> > working with a lot of images of course any help is most welcome.

    >>
    >>
    >> > Thanks!
    >> > Kevin

    >>
    >>
    >>
    >> http://epaperpress.com/ptlens/
    >>


    >Looks pretty slick. The Tokina's not in the database. But it looks
    >like I can submit photos for generating calibration and correction
    >values. Good tool.


    The Tokina *IS* in the data base. I've got the same lens and
    use the same program. The version I downloaded was updated
    as of late April. You may need to download a new data file.

    ----- Paul J. Gans
     
    Paul J Gans, Apr 30, 2006
    #14
  15. k-man

    Paul J Gans Guest

    2 <> wrote:
    ><> wrote in message
    >news:...


    >> It is not a failing of the lens nor program, it's inherent
    >> to rectilinear wide angle images.


    >It is inherent to a cheap, compromise designed "rectilinear" lens. That is
    >one crummy lens.


    My my...

    I rather like mine.

    ---- Paul J. Gans
     
    Paul J Gans, Apr 30, 2006
    #15
  16. k-man

    k-man Guest


    > The Tokina *IS* in the data base. I've got the same lens and
    > use the same program. The version I downloaded was updated
    > as of late April. You may need to download a new data file.
    >
    > ----- Paul J. Gans
    >
    >


    Yep, I had written in my last post that I had found the lens in the
    database. Thanks, though.

    Do you find that PTLens does the trick for you for your Tokina?

    Kevin
     
    k-man, Apr 30, 2006
    #16
  17. k-man

    Guest

    Go-dot wrote:
    > On Sat, 29 Apr 2006 08:15:45 -0500, "2" <> wrote:
    > ><> wrote in message
    > >
    > >> It is not a failing of the lens nor program, it's inherent
    > >> to rectilinear wide angle images.

    > >
    > >It is inherent to a cheap, compromise designed "rectilinear" lens. That is
    > >one crummy lens.


    The picture on the PTLens page is a sample (from a
    fisheye) to show off the program. It's certainly not from
    the Tokina mentioned in the subject line.

    > The "distortion" being discussed is indeed normal for true projection
    > (i.e. straight lines in reallity remain so in the image). When using a
    > flat image plane (i.e. film and/or current CMOS/CCD sensors) you have
    > a choice of either straight lines and "distorted" heads or curved
    > lines and "normal" heads. (You can't change the laws of physics,
    > captain!) Such "distortion" is more properly referred to as wide angle
    > persepective.
    >
    > One potential solution would be the use of a digital sensor with a
    > spherical, rather than flat surface (think of the retina in one's
    > eye).
    >
    > However, the use of such a sensore would be limited to wide angle use
    > as it would present servre problems to normal/telephoto lenses unless
    > the curvature of the sensor could be made to vary as the focal length
    > of the lens in use. Also, the manufacturing of such a device is well
    > beyond current capabilities.
    >
    > I use PTLens (mentioned elsewhere); the current version of the
    > database includes the Tokina 12-24 for the Canon 350D - both of which
    > I own and use. PTLens is easily corrects the slight barrel distortion
    > produced by the Tokina.
    >
    > Nothing can "correct" the wide angle distortion you are referring to
    > without inducing a significant fisheye effect.


    Actually, the sensor shape doesn't really have anything to
    do with it. As long as the _output_ - the print or image on
    your monitor - is flat, you have a choice of fisheye or
    rectilinear distortion, or things in between. But you can't
    make a distortion free wide angle image on a flat surface.
    It's just like the way the Mercator map projection makes
    Greenland look bigger than South America, even though
    it's not. In the real world, our brain's visual processing
    compensates for these distortions so that we think we're
    seeing a wide angle distortionless view.

    Panoramas with cylindrical perspective, like those from
    asembling multiple shots or from a swing lens camera,
    offer a natural looking perspective but make off-center
    straight horizontal lines curved. If you can avoid these lines
    in your picture they look pretty natural. Also huge prints
    mounted like a cyclorama (cylindrical room with 180-360
    degree print on the wall) look good because they
    bypass the problem of making a flat print.
     
    , Apr 30, 2006
    #17
  18. k-man

    2 Guest

    "Go-dot" <nospam@comcastnospamnet> wrote:

    > This clown, aka "2", has no idea what he is talking about. One should
    > just ignore his ignorant ravings. He's obviously clueless about
    > photography and optics.


    Oh, am I? I've been a photographer for almost forty years. I have spent more
    time behind a lens than you have been on earth. I KNOW Biogons. I USE
    Biogons. I also use the rest of the line. So far, digital folks are pretty
    much fucked when it comes to Biogon lenses, but that will eventually be
    fixed when your sensors grow up.
     
    2, May 1, 2006
    #18
  19. k-man

    2 Guest

    "Paul J Gans" <> wrote in message
    news:e32st9$k7i$...
    >2 <> wrote:


    >>It is inherent to a cheap, compromise designed "rectilinear" lens. That is
    >>one crummy lens.

    >
    > My my...
    >
    > I rather like mine.


    I get it: If at first you do not succeed, just lower your standards.
     
    2, May 1, 2006
    #19
  20. k-man

    Go-dot Guest

    On Sun, 30 Apr 2006 18:54:16 -0500, "2" <> wrote:

    >"Go-dot" <nospam@comcastnospamnet> wrote:
    >
    >> This clown, aka "2", has no idea what he is talking about. One should
    >> just ignore his ignorant ravings. He's obviously clueless about
    >> photography and optics.

    >
    >Oh, am I? I've been a photographer for almost forty years. I have spent more
    >time behind a lens than you have been on earth. I KNOW Biogons. I USE
    >Biogons. I also use the rest of the line. So far, digital folks are pretty
    >much fucked when it comes to Biogon lenses, but that will eventually be
    >fixed when your sensors grow up.


    This clown just prooves my point; in fact he's pretty clueless in
    gerneral. By his claim, he's spent twenty years behind the lens before
    he becam a photographer. (Yes, I have personally comercially
    processed E-3 and C-22 films, Super-X films and other things long,
    long gone from this earth).

    A wise man once told me never to wrestle with a pig. You both get
    dirty, and the pig enjoys it. This pitiful troll now enters my kill
    file. PLONK.
     
    Go-dot, May 1, 2006
    #20
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