Tern and why

Roadkill

Why do I have this halo?

Was shooting at the beach this weekend and ended up with a halo in all my shots. I am using a D200 with a Nikon 18-200 VR and a UV filter. The halo seems to be there regardless of focal length. I am feaking out... Any ideas?

pyry

Roadkill wrote:

Why do I have this halo?

Was shooting at the beach this weekend and ended up with a halo in all my shots. I am using a D200 with a Nikon 18-200 VR and a UV filter. The halo seems to be there regardless of focal length. I am feaking out... Any ideas?

I'm not entirely sure I see what you mean. The bird is backlit and so the edges glow a little. Your corners are dark because of lens vignetting. Did you mean either of these or something else?

Roadkill

The corners of the image. That dark area is driving me nuts. What could be causing that?

MikeMcA²

Try shooting without the UV filter and see what happens. Some filters, with very thick mounting rings, can cause this vignetting as the edges of the filter ring show up in the image. On the more expensive filters, you'll notice not only the better quality of the glass, but the thinness of construction.

pyry

Roadkill wrote:

The corners of the image. That dark area is driving me nuts. What could be causing that?

That would be the lens then, it's called vignetting and caused by the effective aperture of the lens changing as the light path moves away from the center. Almost all lenses do that at varying levels. Not something you need to pull your hair out for really - I usually pour more on.

Stopping the lens down helps. It's also easy enough to correct in post if you don't like the effect. (I do think your image improves because of it, consider that )

Filter rings can cause vignetting too as can lens hoods that are not attached properly, but that is a much sharper fall-off, this is purely the lens I think.

JohnDC

Roadkill wrote:

Why do I have this halo?

Was shooting at the beach this weekend and ended up with a halo in all my shots. I am using a D200 with a Nikon 18-200 VR and a UV filter. The halo seems to be there regardless of focal length. I am feaking out... Any ideas?

Consistent with pyry's reply, the Nikon 18-200 has fairly stong vignetting at the longest and shortest focal lengths, as shown in these data from SLRgear.com
Photoshop or plug-in may have a lens-specific correction for this problem.

http://www.slrgear.com/reviews/showproduct.php/product/250/cat/13

SciurusNiger

When I got the D2Xs and big lenses, I had the same "problem" but it's very easy to correct.

With CS2, you can have as much or as little or no vingetting applied to the RAW image by opening it with Adobe Bridge, then using the "Lens" tab to adjust the percentage (as applied from the midpoint).

When I figured this out, I simply set mine to zero and made it the default for all my processing.

Roadkill

Great info, Thank you, it was driving me a bit nuts because I thought I had some equipment problem.

Funny thing is... I shot for years with film and never remember coming across this issue, or maybe I just never noticed it.