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D700 long exposure noise reduction

tjv

Active member
Hello all.
How many of you use the D700's internal long exposure noise reduction? I've been doing some work documenting exhibitions and to make sure I get the least grain and sufficient depth of field, I'm often exposing as speeds up to ten seconds at 200ISO. The results, which are usually high contrast scenes where I need to maintain highlight detail from spot lights (and I don't have time in the budget to do HDR,) look pretty blotchy and lacking detail in the mid to darker tones. I have a feeling the noise reduction is really smearing detail and flattening things out. Would this be true? Do the rest of you get the camera to do NR on long exposures or do you just handle it in post?
Thanks.
 
P

plupcoutrielo

Guest
Because your over exposing. Two seconds mid day is a whole lot of light and ISO 1600 is setting the camera to the maximum sensitivity. Try the following

Take the picture much later in the day or early morning preferable just as the sun is about to come up or the sun has just set.

Set the camera to ISO 100 least light sensitive
Mount the camera on a tripod or some very stable surface.
Set the camera in Av mode and set the aperture to something like f/16
Let the shutter speed float but it will most likely be several seconds.

Take the pic.


But out of curiosity, why are you wanting to take such a long exposure?
 

RichA

New member
Not how long exposure NR works

Long exposure noise reduction does not change image noise, it has no effect on detail. The point of long exposure noise reduction is to eliminate "hot" pixels or pixels that don't behave with uniform sensitivity compared to other pixels and show up as hot spots in images that are a longer than one second in the making. The noise reduction creates a dark frame, which is a blank frame exposed for as long as the original shot. This frame shows the same hot pixels as the initially exposed frame. The dark frame is then subtracted from the original image, taking the hot pixels with it. The original image is now cleaned of the hot pixels. Nikons, particularly lower-end D80/90s all seem to have hot pixels, but it can happen to any camera, hence dark frame subtraction. Dark frame subtraction originated from astronomical shots done over periods of minutes with CCD imagers.
 
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