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08-21-2012, 04:25 AM   #1
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Bulb Mode- nr on topside LED after long exposure

I purchased a Lee 10 stop ND filter and I took a few test shots in the backyard in Bulb mode with a wired remote. I would expose the shot for 70 seconds and release the trigger on the remote. It sounded like the exposure was complete but I would get an "nr" on the top LED and nothing else seemed to work on the camera.
I briefly read on a google search that it means the camera is doing some sort of noise reduction.
My question is why and also whether I could (& should) shut that automatic function off?

I plan to read about this topic in the K5 manual after work today, but for now I wanted to post my question.

08-21-2012, 04:50 AM   #2
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Turning off in-camera noise reduction depends on your objective and/or whether you will use post processing to remove unwanted noise. As I understand it, how in-camera noise reduction works is to take a second equally long exposure with the shutter closed. The camera then removes anything from the first exposure that wasn't pure black in the second exposure. I'm sure it is more accurate than doing NR via post processing, but it does effectively double the time your camera is unavailable to take another photo.
08-21-2012, 08:53 AM   #3
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It's called DFS (dark frame subtraction), it kicks in after 30s, it's annoying, and it can be completely disabled on the K-5.
08-21-2012, 02:10 PM   #4
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Well it's good to know that my camera isn't broken. That was the first thought. I guess I'll leave it on by default.


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