What would cause these striations in bokeh?

[boxofrocks]

Take a look at these photos--no post other than resizing.

These were shot on a D200 w/Sigma 120-300 @ f/4 and about 1/2000. What might be causing the strange linear striations in the bokeh?

[Daniel Bates]

Wires in the background maybe? I don't see the lines in the OOF grass.

[boxofrocks]

Nope--no wires. you can see them on the track, too.

In the last shot you can see them on the grass.

I'm at a loss.

[smoothassilk]

What Scott said.

[srwatters]

A type or Moire?

[DEMDeepEllumMusic]

Ok lets think this through a bit.
Your censor in your camera is basically a grid of cells.
The effect seems to be the strongest on vertical or parrellel lines that have sun hitting them.
Maybe you have found a rare situation where the two line up and create this problem?

( if this field is nearby and you are not busy around the same time today go out and set up in the same area and reshoot a few shots like this to see if it will occur again and then take a few with the camera tilted ever so slightly off of the + axis and see if the effect goes away or decreases. If the effect disappears with the camera off center on the horizon then you know you discovered a weird effect if not then maybe that field is haunted! or has some connection to some other ethereal plane that doesn't like it's background being brokeh.) :)

[boxofrocks]

Originally Posted by DEMDeepEllumMusic

Ok lets think this through a bit.
Your censor in your camera is basically a grid of cells.
The effect seems to be the strongest on vertical or parrellel lines that have sun hitting them.
Maybe you have found a rare situation where the two line up and create this problem?

( if this field is nearby and you are not busy around the same time today go out and set up in the same area and reshoot a few shots like this to see if it will occur again and then take a few with the camera tilted ever so slightly off of the + axis and see if the effect goes away or decreases. If the effect disappears with the camera off center on the horizon then you know you discovered a weird effect if not then maybe that field is haunted! or has some connection to some other ethereal plane that doesn't like it's background being brokeh.) :)

That doesn't make sense on the last one though. There are no lines running parallel to the frame on the field.

I'll look through some other examples when I get a chance.

[bondarnes]

Were all of these images shot at the same focal length?

[GregO]

Possibly a couple of combined factors:
#1 Depth of field
#2 Heat

The shallow depth of field causes the blurred effect generally desired for these shots and heat waves created distortion in the otherwise linear features making the look bent or "wavy".

The image of the kicker is most interesting due to the fact that the lines in the stands appear to have some light reflective quality. This may have been caused by the sun hitting the metal benches. Since there are no fans sitting there I cannot confirm this theory.

Just my 0.02 worth from a forensic perspective.

[boxofrocks]

Originally Posted by bondarnes

Were all of these images shot at the same focal length?

Yup.

[boxofrocks]

Here's another example with the same lens at 300mm and different aperture, s/s, and lighting conditions:

[ratbert]

Tom,

Could this be the banding issue that Nikon said exists in some early production D200's?

http://www.dcviews.com/press/Nikon-D200-banding.htm

[boxofrocks]

Originally Posted by ratbert

Tom,

Could this be the banding issue that Nikon said exists in some early production D200's?

http://www.dcviews.com/press/Nikon-D200-banding.htm

Well, I'm not saying it isn't, but I've never seen it with any other lens..

[Joe_Lorenzini]

My first impression is that it's not related to the banding issue as I've never seen D200 banding this large or as obvious. It really does look like a lens issue (to my untrained eye).

All I can suggest is more experimentation Tom. See if you can duplicate these results. If you can, I'd suggest sending the lens back. If this is a result of this particular lens it's unacceptable.

_/oe

[NathanJK]

Do you have another lens that can equal this, such as a 70-200? If so I'd take a picture with each at equal focal lengths, apertures, and conditions and see if it shows up in both. I'm fairly certain its actually a lens issue, but its worth checking. If it shows up in both, blame the body, if it shows up in the sigma only blame the lens! Have you gone out and taken any more pictures since you shot these with the sigma to see if its showing up still? Also, I'm curious...if you try intentionally de-focusing the lens, will you see it everywhere in the image? I suspect you will.