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  1. #1
    Join Date
    Jan 2005
    Posts
    16

    Sigma 10-20 is there a problem with the lens???

    Hello,

    I posted the following message on the Sigma forum and didn't receive many responses.

    I bought the Sigma 10-20 F 3.5 for my D80. Unfortunately I didn't have a chance to test it before our trip. Attached are two examples where there is extreme distortion in my son's face. Shots taken without a person seem fine. Shots taken where the person was in the center of the frame seem fine. Both shots were taken at 17mm. I have a 16-85 Nikon, and have never had any issues at 16.

    Bottom line, do you think I have a defective lens, or is this what I have to expect from an extreme wide angle?

    Probably a stupid question, but is there any way to fix this post processing?

    I am about to head to Banff, and it really makes me think twice about using this lens with people and scenery.

    Thanks for any advice.

    Kcbryan
    Attached Images Attached Images   

  2. #2
    Join Date
    Dec 2007
    Location
    Upstate NY USA
    Posts
    839

    RE: sigma distortion

    Looking at the second picture there is a similar distortion of his knee. I suspect that it is a characteristic of that lens, especially when you are picturing people close to the lens at the edges of the field covered by that lens. The scenery in the background appears to be fine. You would likely get a similar distortion on people in the center if they were very close. Noses, chins or foreheads would be distorted in proportion. They would tend to look very fat, like a cartoonists caricature that exaggerates certain features of a person's face. This could well be normal for that lens and not indicative of a defect in manufacture. Especially since the distortion is consistent on both edges of the frame, mirroring each other. Try taking a picture where his face is in the exact center of the side area and not high or low. This distortion could well be minimized that way. As it is the glasses on his face tip up toward the upper corners of the frame. Another way to lessen this distortion is to have people be a bit farther away from the lens.
    As far as PP removal I would defer to the appropriate experts in that field.
    Last edited by Falconest174; 06-19-2010 at 10:00 PM. Reason: add text
    Falconest174
    Seeing the picture starts the process
    D7100, Sigma 150 f/2.8 Macro, Tamron 70-300 Macro, Sigma 17-70 F2.8 Macro,
    Tamron 70-300 Di VC USD 60Th Anniv. ,SB700, Vivitar 383, Manfrotto t-pod, monopod
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  3. #3
    Join Date
    Jul 2005
    Location
    Sydney, Australia
    Posts
    4,428
    I'm not sure if there is a problem with the lens but ultra wide lens is not recommended for taking shots of people and I suspect that's the reason. You will see much distortion on the subjects.
    Nikon D90, D80
    Nikkor 16-85mm AF-S DX F/3.5-5.6G ED VR, Tamron SP AF 28-75mm F/2.8 XR Di LD Aspherical (IF) macro, Nikkor 50mm F/1.4D, Nikkor 50mm F/1.8D, Nikkor AF-S VR 70-300mm F/4.5-5.6G IF-ED, Sigma 105mm F/2.8 EX DG Macro ||| 2x SB800 | SB600 ||| Manfrotto 190XB

  4. #4
    Join Date
    Mar 2005
    Location
    London
    Posts
    1,887
    Totally normal. The only way I take photos of people with that lens is if they are dead centre. If more than one person and they are not dead centre, I zoom into 20mm as this helps a bit with the distortion.

    Agree with tim11, not recommended for taking "People" shots!
    Nikon D700
    Sigma 70-200 F2.8
    Sigma 85mm F1.4
    Sigma 15-30 F3.5 - 4.5



    http://www.philipduartephotography.com

    "It's better to be hurt by the truth than comforted by a lie"

  5. #5
    Join Date
    Jun 2007
    Location
    Somerset, England
    Posts
    718
    As to fixing it, what software do you have? Most image processing software these days has built-in tools for fixing distortion of this nature. I don't know how well it would work in this case but it's worth giving it a try.
    Gear List:
    Canon 40D + Sigma 18-50mm + Canon 55-250mm

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  6. #6
    Join Date
    Jan 2005
    Posts
    16

    Thanks

    All,

    Thanks for the info. It makes me feel better. I was kind of expecting that, but what had me wondering was that both shots were at 17mm. If they were at 10mm I would have definately thought so. I have never noticed this with my 16-85. Maybe I don't shoot at 16 as much as I thought I did, or maybe 17 on the 16-85 doesn't distort as much as on the 10-20.

    As far as pp, I don't have anything good right now. I am about to get NX2, but have only played around with the trial.

    Thanks again,

    Kcbryan

  7. #7
    Join Date
    Dec 2006
    Location
    So Calif
    Posts
    3,226
    Looks normal. Nice colors and sharpness. You can shoot some sides of cars (tires) to test the distortion at various focal lengths and framings.
    Pentax K20D/K5/15/21/40/70/10-17/12-24, Sigma 17-70 2.8-4.5/150-500, Tamron 90 Macro/70-200 2.8, Canon SX20 IS/Elph 500HS
    (formerly Pentax 50 1.4/50-200/55-300/K100D, Sigma 18-50 2.8/70-300 APO, Tamron 28-75, Viv 800, Tele-Tokina 800, Canon S3 IS, Samsung L210)
    http://s133.photobucket.com/albums/q78/KylePix/

  8. #8
    Join Date
    Mar 2005
    Location
    London
    Posts
    1,887
    Might be helpful?!

    http://www.ephotozine.com/article/Wi...ne+(ePHOTOzine)

    Saw it and thought of this thread...
    Nikon D700
    Sigma 70-200 F2.8
    Sigma 85mm F1.4
    Sigma 15-30 F3.5 - 4.5



    http://www.philipduartephotography.com

    "It's better to be hurt by the truth than comforted by a lie"

  9. #9
    Join Date
    Jun 2006
    Location
    Orlando, FL
    Posts
    285
    That is definately normal and part of the learning process with ultra-wide at the 10mm end. I take a lot of photos of house interiors and have to be consious of the angle and pitch. Common well known objects like doors, refrigerators, derssers will get an elogated distortion like the knee. Sometimes it happens in post processing as I am fine tuning the perspective - making horizonals horizonal and verticals vertical.
    Digital: Nikon D40; Nikon D90; Nikon D7000 Nikkor 18-55; Nikkor 55-200VR; Sigma 10-20; Tamron 17-50; SB-600; SB-900; Pocket Wizards
    Film: Canon AE-1; T70; FD 28mm 2.8; FD 50mm 1.8; FD 135mm 3.5
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