What caused this?

[photophorous]

Hi Everyone,

I recently tried a few long exposures with my D70s...5-10 minutes. Each one of them showed this purple cloud looking part in the upper left corner. Does anyone know what could have caused this? Is this a camera defect, or did I do something wrong?

Thanks,
Paul

[freygr]

Hi Everyone,

I recently tried a few long exposures with my D70s...5-10 minutes. Each one of them showed this purple cloud looking part in the upper left corner. Does anyone know what could have caused this? Is this a camera defect, or did I do something wrong?

Thanks,
Paul

No you have pushed the limits of sensor and that is noise! You need to use the techniques that the Astronomers use. There is a web site, about the techniques was posted in one of the threads.

[Sebastian]

Heat.

Heat affects the exposure, it's caused by the controller chip sitting right by the corner of the CCD.

Not sure if long exposure noise reduction would counteract that, but you can try it.

[photophorous]

Thanks for the comments, guys.

I didn't think to try long exposure noise reduction. I'll see if that works.

Paul