Weird Colour Gradient at High Shutter Speed

[praesentire]

Hi all,

I've been playing with my 50mm f/1.8 on my D70 and I've noticed something weird. Whenever I shoot at 1/5000 and faster, the image comes out with this tint gradient across the image. It goes from greenish to magentaish. See below.

<a href="http://www.flickr.com/photos/praesentire/1241689520/" title="Photo Sharing"><img src="http://farm2.static.flickr.com/1370/1241689520_11cd998faa.jpg" width="500" height="332" alt="DSC_3060" /></a>
Camera: Nikon D70
Exposure: 1/8000 sec
Aperture: f/2
Focal Length: 50 mm
Exposure Bias: 0/6 EV
ISO Speed: 200
Exposure Program: Aperture priority
Metering Mode: Center Weighted Average

I never shot a scene with a shutter speed faster than 1/1250 before so this has never been a problem for me. Changing the white balance mode does not seem to matter.

Does anyone know what causes the gradient? Is this something specific to the D70?

[wulf]

I've not seen it before but I rarely get anywhere near that fast. You probably could have gone a bit slower on that shot anyway, as it looks a tad underexposed. It would be worth doing some more experimentation to see if it always happens or if it was just that particular scene.

Wulf

[praesentire]

You're absolutely correct in that I should stop down for this scene.

I guess 1/8000 on a D70 just means "Got an ND filter?" or "Stop down a few will ya?". This issue becomes less and less pronounced towards 1/5000.

[wulf]

It might be something to do with the physical action of the shutter - 1/8000s is very quick, so part of the image is probably obscured by the shutter in motion. It is a physical movement and so takes a discrete amount of time to occur.

Wulf