D70 strange light concentration and horizontal lines

[agjell]

I discovered this problem the first time I took night-pictures of the sky. After shooting I went back to my computer and imported the images. I noticed a strange concentration of light located in the upper left corner of all my pictures. To better be able to see it I turned up the EV compensation and found another bothering thing; in addition to the light concentration there were lots of horizontal lines stretched across the picture. I decided to do some tests and find out where the problem lied. To eliminate the lens as a problem source I removed it and put the body-cap on the camera instead. I took a couple of pictures with different shutter speeds and ISO values. What I found was that the horizontal lines were there every time, but not in the same places, they were obviously not the same lines. Somehow they were, and still are, generated by the camera, but can only be seen on very dark pictures. The upper left light concentration occurred gradually more from about 10 seconds shutter speed and upwards, independent of ISO values. This is extremely frustrating! I included my test setup below and encourage other users to test their cameras as well.

Test setup: Remove lens. Attach body-cap to camera. Turn mode-dial to “M”. Select settings ISO 200, 30 seconds shutter. (Aperture can obviously not be set because the lens is not attached.) Take picture.

I processed the image using Photoshop CS and Camera Raw 2.4, but I’ve also verified that I got the same result with Nikon View.

My CR settings in PS were:
White balance “as shot” (4800 -4)
Exposure +4
Shadows 0
Brightness +150
Contrast +25
Saturation 0

These settings will clearly present you with the problem if you have it.

This is my test picture.

[Mig]

You might be interested in this thread.

Danielle

[DownByFive]

Yeah, it's what's commonly referred to as "amp glow". I've only seen it under the test conditions, but I don't take too many long exposures...

[AgmLauncher]

unfortunately i have the same issue which sucks as i was planning on using the camera for "long" exposure astrophotography myself. However setting the camera to ISO 200 has fixed the problem for me. This would be advisable for you since it's best to trade exposure time for less noise for astrophotography anyway. Hope you're able to work it out :/