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Photo

I don't believe this is noise, so what is it and how do I get rid of it?

long exposure time lapse night stars

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5 replies to this topic

#1
JWP763

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So, I'm trying to teach myself time lapse long expose shots so I could really capture the movements of the stars. I haven't done much reading up on it mostly because I could find any good info so I just winged it and I think my first try was pretty successful. For the photo I used a D7100 with an 18-55 wide angle Nikkor lens. I had about a 45 minute exposure time with f/22 and anISO of 100. I'm happy I was able to capture the stars movement but if you zoom in on the attached image, it's covered in a mixture of grey, red, green, and blue dots. I don't believe this is noise and I tried noise reduction using Lightroom buy it didn't do much. Any idea what it is and where I'm going wrong??

#2
Adam

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That's definitely noise, most likely caused by sensor heat.  What you'll want to do is enable slow shutter speed noise reduction (dark frame subtraction) in the camera.  This will start running as soon as your exposure finishes, for the duration of the original exposure (45 minutes in this case).

 

For an exposure that long I don't see a viable alternative to DFS, though attempting to reduce color noise during raw development may help.



#3
OTRTexan

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Most star trail images you see are actually many separate exposures, usually about 30 sec each, stacked on each other using software.


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#4
Rontography

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Most star trail images you see are actually many separate exposures, usually about 30 sec each, stacked on each other using software.
 

 

This. There is a lot of good info on the subject, I read a lot about it several years ago. Stacking is the way to do it. 



#5
Tony

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Okay, I give up, where is the image?

 

thnx, Tony



#6
JWP763

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Thanks guys, I'll give it a try next time, I thought the image uploaded but I guess not





Also tagged with one or more of these keywords: long exposure, time lapse, night, stars