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Hi All

I just got myself a K100D 3 weeks ago, which came with a Sigma 18-50 f3.5-5.6. I am moving up from a Canon S3 IS, so I am learning all about different lens ranges and speeds.

I picked up a Sigma 28-70mm f2.8-4 on eBay for A$30 (US$24). In playing with this lens today, I find some of the photos come out hazy, such as these two:

http://farm2.static.flickr.com/1106/540 ... 7e0210.jpg

http://farm2.static.flickr.com/1254/540 ... 9a24b3.jpg

They were shot in RAW, and converted to JPEG by Aperture. I haven't done any PP to them. If i click on "Auto Levels" in Aperture, it will fix much of the haze, but I want to learn and understand the cause, rather than how to fix it in PP.

About 10% of my shots with this lens come out like this. I thought is was flaring from the sun, which also occurs, but the 2 above were not pointed at the sunlight.

It is not occurring at a particular focal length. Any ideas what causes this?

Cheers

Jeff

Does the lens have a UV filter on it?

No, no lens filter on it Philip.

Look through the lens and see if it is nice and clean and the elements or lens are clear...... if not it may need a clean

the lens may be back focusing, have you tried it with manual focus?

Look through the lens into a light, open the aperture fully by slightly moving the lever on the back on the lens, see if there is any sort of 'spider-web' looking stuff inside.

Yi-P wrote:Look through the lens into a light, open the aperture fully by slightly moving the lever on the back on the lens, see if there is any sort of 'spider-web' looking stuff inside.

Not a spider web, but a "smudge" and some "spatters". I tried to clean it with a glasses cloth, but it doesn't rub off. It's as if it is on the other side of the glass, inside the lens.

How could that happen?

How is the camera when you shoot in full sunlight and not in the shade?

servaasproducts wrote:

Yi-P wrote:Look through the lens into a light, open the aperture fully by slightly moving the lever on the back on the lens, see if there is any sort of 'spider-web' looking stuff inside.

Not a spider web, but a "smudge" and some "spatters". I tried to clean it with a glasses cloth, but it doesn't rub off. It's as if it is on the other side of the glass, inside the lens.

How could that happen?

With improper storage, very easily.

If the lens has fungus, or other issues, then you'll see a reduction in contrast, or other problems with the images.

What do images shot with the other lens you have look like?

Is it possible for you to shoot pairs of similar images, but shooting first with one lens, and then trying to shoot the same image with the other lens?

This was we can isolate the problem to either a lens, or the body, or to user technique.