Sun 18-Sep-11 03:21 AM | edited Sun 18-Sep-11 03:45 AM by DigitalDarrell
Not really because Long exp. NR uses the dark frame (black frame) subtraction method for noise reduction, which is much less destructive to the image than regular "blurring" noise reduction.
In black frame subtraction, two exposures are taken. One is the original exposure and the second an exposure with the shutter closed. The second exposure is a dark frame that shows only the noise. That locations of the noise in the second dark frame image are subtracted from the first image, without massive blurring and resharpening.
Also, with the D7000, the second exposure is often less than the length of the first exposure, unlike earlier Nikons, which require two exposures of identical length.
I leave Long exp. NR set to On all the time. This type of noise reduction does not affect regular grainy noise in the image, just amp noise (heat noise) and hot or bright pixels that show up on longer exposures. They are subtracted from the original frame because the location of the noise should not change over the course of two subsequent exposures.
I find it interesting that Nikon's firmware update has reduced the time from 8 seconds to 1 second before turning on Long exp. NR. Could it be that the D7000's sensor is more sensitive to heat buildup for longer exposures. I am going to have to do some research on this issue.
============================================== Darrell Young (DigitalDarrell) www.pictureandpen.com "Better too many words than not enough understanding." ==============================================