What would cause these striations in bokeh?

[kenw]

doubt it is lens as the orientation is ALWAYS aligned with some physical object.

my theory? It is compression banding. You see it is in sunsets and other images where "similar" tones, shades and whatever are combined via the compression algorithm, be it jpg compression or any other (yes, TIFs can be compressed). The compression combines similar pixels to reduce the file size. These happen (for one reason or another) to be similar enough so that the algorithm goes ahead and combines them.

The fix? don't compress so much or use a different compression algorith, (there are many, some better than others).

[dminton]

Internal reflections and refractions within the lens.

[boxofrocks]

Looks like I stumped the band:

From Sigma:

Tom,

I have been reviewing your images with the technical staff here in NY. We have forwarded your images to Japan to get some feed back from them. Please give us some time to investigate this further.

[DEMDeepEllumMusic]

Come on TOM, you don't think it is just a banding issue?

[boxofrocks]

Originally Posted by DEMDeepEllumMusic

Come on TOM, you don't think it is just a banding issue?

I'm not sure if you're serious, but would a banding issue show up with only one lens? I've never seen this on any other lens with this body, and I've used about 5 different ones.

[DEMDeepEllumMusic]

(I was joking, good luck on the quest).

[Roy]

Good luck. Hope it is the lens and Sigma takes care of you on it.

[boxofrocks]

Originally Posted by DEMDeepEllumMusic

(I was joking, good luck on the quest).

Thanks! I'm at a loss, myself.

[chloew]

They look like diffraction patterns.

Do you have any kind of filter on this lens? I was thinking that a linear polarizer might do this.

[Seymore]

Tom... I'm seeing that the EXIF on the first image shows a D2h and the third image is a D200. So, were you shooting with 2 different bodies that day? If this is the case... I think we can rule out the body as the culprit and can only suspect that the problem resides with with the lens itself.

Might I also suggest that the next time you're in an outdoor/daylight shoot, you stop the lens down a bit (f8) and see if you still have this problem. Also, is it a possibility that you can rent, or borrow, a Nikon 300/4 lens to do a side by side comparison?

I also look forward to hearing/reading what Sigma has to say about this.



UPDATE: I just had a brain storm! 1st image... On the front side of the seats/bleachers, are there groves running parallel to the seat? Chance that these are what is causing this issue? And, on the 3rd image... could that be fencing? However, I know this doesn't explain your last image. But, it just a thought...

[boxofrocks]

Originally Posted by Seymore

Tom... I'm seeing that the EXIF on the first image shows a D2h and the third image is a D200. So, were you shooting with 2 different bodies that day? If this is the case... I think we can rule out the body as the culprit and can only suspect that the problem resides with with the lens itself.

Might I also suggest that the next time you're in an outdoor/daylight shoot, you stop the lens down a bit (f8) and see if you still have this problem. Also, is it a possibility that you can rent, or borrow, a Nikon 300/4 lens to do a side by side comparison?

I also look forward to hearing/reading what Sigma has to say about this.



UPDATE: I just had a brain storm! 1st image... On the front side of the seats/bleachers, are there groves running parallel to the seat? Chance that these are what is causing this issue? And, on the 3rd image... could that be fencing? However, I know this doesn't explain your last image. But, it just a thought...

I forgot to metnion I was using two bodies. Duh.

No fencing, by the way. That doesn't explain what I'm seeing on the turf, either.

[boxofrocks]

Originally Posted by chloew

They look like diffraction patterns.

Do you have any kind of filter on this lens? I was thinking that a linear polarizer might do this.

No filter.

[Silvernic]

I would definitely rule out banding issues. I looked into this quite a bit when I first got the D200 and these are definitely not the type of situation where you would notice it.