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11-04-2010, 10:16 PM   #1
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K7 30 sec exposure problems

I have a k7 and set it up with takumar lenses. I was out shooting a 30 sec exposure of the street at night with an iso level of 100. My picture had some dots on it like static with green, red, orange, blue colors. However once I use a faster shutter they are gone. So i ran some tests with the lens cap on to make sure I don't have dead pixels. The same results. At 1/50 shutter nothing showed up. At 30 sec there is a lot of noise. I have two k7 cameras and both are the same. Anyone else have this problem? Is there a setting I have that makes it this way. Thanks

11-04-2010, 10:36 PM   #2
Wheatfield's Avatar

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Run pixel mapping.
You could turn on noise reduction as well.
11-05-2010, 02:15 AM   #3
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I had the same problem. Must try this night with my K-5...

Pixel mapping will not help, because it is only at 30 sec exposure...
11-05-2010, 02:33 AM   #4
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Long exposure with the K-7 at ISO100 is usually pretty clean.
Try setting Long Exposure Noise reduction on at 30secs - that seems to be the limit of what the sensor can handle without NR

11-05-2010, 04:11 AM   #5
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Do the pixel mapping anyway, it'll help at least some; works for me. And as suggested, you could also turn on dark frame subtraction, that'll work for sure at the cost of the 2X exposure time, 1X for exposure and 1X for the dark frame.

i do a lot of long exposures, these 2 things keep the hot pixels out. Of course, the K-7 sensor also has a lot of noise in the dark areas of the image on long exposures. Because of that i tend to try to keep my long exposures as short as possible.


And long exposures with the K-7 should always be at base ISO. i've run tests and image noise is prominent should i up the ISO.
11-05-2010, 02:37 PM   #6
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"Turn on the dark frame subtraction"? Is there a way to turn it off? If so, I sure didn't know about it!
11-05-2010, 03:32 PM   #7
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QuoteOriginally posted by fewayne Quote
"Turn on the dark frame subtraction"? Is there a way to turn it off? If so, I sure didn't know about it!
Custom Item 18 : Slow Shutter Speed NR

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