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

[kcbryan]

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

[Falconest174]

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.

[tim11]

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.

[herc182]

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!

[Paradox]

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.

[kcbryan]

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

[SpecialK]

Looks normal. Nice colors and sharpness. You can shoot some sides of cars (tires) to test the distortion at various focal lengths and framings.

[herc182]

Might be helpful?!

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

Saw it and thought of this thread...

[tizeye]

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.