what's causing this?

[sean7488]

I was out testing my new lens, a sigma 10-20 4-5.6 for nikon, and I took some pictures into direct sunlight to test out the flares. I've never seen this before and was wondering what would be causing this in the picture below. I think it's flare but I could be wrong.

 

[Lodd]

Do you have a filter on the lens? if that's the case. what filter?

 

[sean7488]

nope no filter

 

[Lodd]

Do you have another lens this wide you can test with? I dunno if the problem disappears if you try using a smaller aparture. you don't have any reason to shoot @ ƒ/4 in this weathercondition. Try reshooting at ƒ/11 or so. (or get more high quality glas )

 

[KmH]

The bright lines are reflections internal to the lens, and are caused in part by the wicked, complex barrel distorion the lens has.

DP Review notes:

Flare

Control of flare is a critical feature of a superwide lens; with such a broad view of the world, bright light sources will find themselves in the frame on a regular basis. The Sigma 10-20mm generally deals with this reasonably well, but can run into problems in more difficult circumstances.
With the sun placed directly in the frame at wideangle there are generally few really objectionable effects, but as is often the case, stopping down for sharpness or depth of field substantially increases the visibility of flare patterns. In these situations you'll have to choose your aperture carefully, to balance sharpness against flare.

 

[tom r]

try shooting with a polarizer when shooting in the suns direction.

 

[sean7488]

Do you have another lens this wide you can test with? I dunno if the problem disappears if you try using a smaller aparture. you don't have any reason to shoot @ ƒ/4 in this weathercondition. Try reshooting at ƒ/11 or so. (or get more high quality glas )

It's my widest lens, I tried it on both of my d90's and each got the same result. I suppose it could be the glass but idk for sure. I read a lot of reviews about the lens and most say they like it. The other pictures I took were good enough, I was just wondering what would be causing something like that. I took a different shot at a different location at around f/13 and got the same result so I don't think it's the aperture.

 

[sean7488]

The bright lines are reflections internal to the lens, and are caused in part by the wicked, complex barrel distorion the lens has.

DP Revew notes:

Flare

Control of flare is a critical feature of a superwide lens; with such a broad view of the world, bright light sources will find themselves in the frame on a regular basis. The Sigma 10-20mm generally deals with this reasonably well, but can run into problems in more difficult circumstances.
With the sun placed directly in the frame at wideangle there are generally few really objectionable effects, but as is often the case, stopping down for sharpness or depth of field substantially increases the visibility of flare patterns. In these situations you'll have to choose your aperture carefully, to balance sharpness against flare.

interesting, thanks for the information.

 

[fokker]

try shooting with a polarizer when shooting in the suns direction.

Not really sure that would help control flare, it would possibly even make it worse.

 

[pbelarge]

try shooting with a polarizer when shooting in the suns direction.

Not really sure that would help control flare, it would possibly even make it worse.

I agree.
It is my understanding that with uwa and wa lens, this is a trait and to be expected. Think about it, that sun is direct in the lens.

BTW:
I think it looks pretty cool, even if that was not the intended result.

 

[sobolik]

It has nothing to do with barrel distortion. Barrel Distortion: Optical: Glossary: Learn: Digital Photography Review

It is caused by the sun rays entering the lens. If you don't like it then stop shooting into the sun as such. It is just the nature of the two combined - sun angle and glass lens camera.

About the only thing you could do to maybe control it somewhat is use a star filter to MAYBE prevent complete random things like the spot.