Stray Light

[geordie1970]

I was looking through my images on the pc and noticed this

not a great photo but what is causing the spots of light is it just a dirty poor quality filter or something much worse

[HowlinWolf]

The streaks of light is lens flare, which is non-image forming light. This is caused by a light source (in this case, the sun) hitting the front element of the lens, and can be prevented by fitting a lens hood (I never shoot without one), or using something to shield the lens during exposure. Any dust or dirt on the front element (or filter) will make it worse, although with the right subject it can be used to creative effect.

HW

[geordie1970]

Thanks Howling Wolf I was using a sigma 10-20mm lens with hood but it was a very bright day.

[HowlinWolf]

Yes, lens hoods on ultra-wide lenses are sometimes as much use as the proverbial ........(fill in appropriate subject). Under such circumstances as you have encountered here, it is worth trying to find something out of shot to try and block the sun, such as a tree branch or other object. When I shoot landscapes I try to stand so that my shadow falls across the lens, especially when I'm using ND graduated filters. Lens flare degrades the image and reduces contrast, so it's best avoided where possible.

HW