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Old Jun 21, 2006, 5:50 AM   #1
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allanseiman's Avatar
Join Date: Jul 2005
Posts: 4


i have just noticed that in some of my pics i get a few red spots while i shoot pics at night. i have just bought the nikkor 50mm 1.4d and wastaking a few test shots from the balcony at night, thats when i noticed the spots. they are consistenly at the same spots.thinking that it is dust i cleaned the camera and the lense and tried again but it didnt work. the spots where there. when i reduced the aperture i didnt get the spots. why would this happen.if you need to see the pics please send me your email id and ill send the pics to you. when i reduce the size of the picture the dots are not visible. also i dont want to upload the pic in a smallere size as it is of no use ... you cnat see the dots there.

using a nikon d50 . noise reduction is setto off.

shutter speed is 3

iso is 200

aperture is set to 1.4.

please help .

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Old Jun 21, 2006, 7:29 AM   #2
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Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378

It's probably just some hot pixels (common on long exposures). Turn on your noise reduction. That's what it's there for (it's entire purpose is to get rid of hot pixels on exposures of around 1 second or longer).

It works by taking an extra photo using the same settings, only with the shutter closed. It then searches for any hot pixels in the dark frame (shutter closed) exposure and maps them out of the actual photo by using values interpolated from adjacent pixels.

Because the two photos are taken at the same time, at the same camera temperature, any hot pixels are likely to be in the same locations (so it knows where to find them in your photo, based on where it finds them in the dark frame photo taken at the same time).

This technique is known as dark frame subtraction noise reduction.

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