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06-01-2014, 07:27 PM   #1
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Total overexposure on Star Trail attempts

I'm getting total overexposure on taking photos at night in an attempt to get a star trail image. Any suggestions? Exif info is here to examine

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06-01-2014, 07:47 PM   #2
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Evening Michael,

I see from the images EXIF that it was a 28 minute exposure at ISO 200, f4. I would try some experimentation using 30 seconds and then perhaps 1 minute (using the bulb mode). You should get some short trails with that. So, lets say that your happy with 30 seconds. Then just take a series of 30 second shots back to back for however long and then stack them up in a post processing utility, to string the star trails together.

06-01-2014, 08:48 PM   #3
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Lower the ISO, shoot at a higher aperture. Alternatively, do what was previously mentioned and simply lower the exposure time.
06-01-2014, 08:51 PM   #4
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If you really want long exposure, something like ISO 100, f/4.5, 10minutes should expose properly. But as mentioned, you should take multiple 30 seconds exposure and stack them. I had decent results with ISO 1600, f/4, 30 seconds. 1 minute will create less images to stack and will permit lower ISO. (800,f/4,1m). Your mileage will vary. Try out a few settings and see how it turns out for you

06-01-2014, 09:38 PM   #5
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Bear in mind that the moon will wash out the sky on long exposures. For the darkest sky wait until the moon is below the horizon and get far away from lights. At least 30 miles from cities and towns.
06-02-2014, 07:47 AM   #6
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Free stacking software utility...

Last edited by interested_observer; 06-02-2014 at 08:02 AM.
06-02-2014, 10:00 AM   #7
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Perhaps I could try the "interval" option with my camera. I have never tried it before, but I read if you set the exposure for 45 seconds, then set the next interval for 46 seconds or more.
06-02-2014, 11:18 AM   #8
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QuoteOriginally posted by Michael Piziak Quote
Perhaps I could try the "interval" option with my camera. I have never tried it before, but I read if you set the exposure for 45 seconds, then set the next interval for 46 seconds or more.
With the built in intervalometer you won't be able to use exposure longer than 30 seconds (>30 seconds requires you to use Bulb). But you are right, set interval for 31 seconds. If you want to take longer exposure, you'll need an external intervalometer which can control the exposure time while in Bulb mode.

06-02-2014, 02:47 PM   #9
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Two words: light pollution. There is no other way a night sky could possibly wash out like that.

You need to get away from city lights. Head to the mountains or something. It is virtually impossible to get decent star shots from in or near a city no matter what settings you use.
06-02-2014, 06:28 PM   #10
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QuoteOriginally posted by Michael Piziak Quote
Perhaps I could try the "interval" option with my camera. I have never tried it before, but I read if you set the exposure for 45 seconds, then set the next interval for 46 seconds or more.
Here are a couple of additional suggestions. You do need to get away from the city lights. How far is far enough, when and where? Good Question. Try this link.

You need to find a time when the moon is not shining or out. There are a number of websites that provide the moon rise and setting times. Find a time during the night - either before the moon comes up, or after it sets. If it does not work one evening walk forward to find a day that does work for you.Here are some other web sites...You can find dark sky locations here - its a google map, just zoom in and find a location near you that will work.The eastern US is pretty saturated with light, however that does not mean all is lost. Take a look at this link.It was shot near the outer edge of a Yellow zone and things turned out pretty well. I was shooting away from the city center or out to the dark area. Also, see if there is some terrain that you can put between you and the lights. After finding a good location, then -
  1. mount the camera on the tripod, aim it at something, focus to infinity, set the ISO to the lowest you can go then put it into P mode.
  2. You want to adjust both the aperture and shutter speed.
  3. Select the largest aperture (smallest f number) and try say 10 seconds.
  4. Take a look at the image - too dark (go to 15 seconds), or too light (go to say 8 seconds). You can also adjust the aperture as appropriate (or needed) but you will probably stay with the lens wide open.
  5. Wash and repeat, until you get a shot that you are happy with. Then, using that aperture and shutter speed, take 20 or 30 images in quick succession. These are the ones that you will want to stack in order to get a composited result that has the star trails.
Shooting at night is a lot of trial and error.

Here is a video .....

Last edited by interested_observer; 06-02-2014 at 06:42 PM.
06-02-2014, 06:40 PM   #11
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QuoteOriginally posted by interested_observer Quote
Here are a couple of additional suggestions. You do need to get away from the city lights. How far is far enough, when and where? Good Question. Try this link.

You need to find a time when the moon is not shining or out. There are a number of websites that provide the moon rise and setting times. Find a time during the night - either before the moon comes up, or after it sets. If it does not work one evening walk forward to find a day that does work for you.Here are some other web sites...You can find dark sky locations here - its a google map, just zoom in and find a location near you that will work.The eastern US is pretty saturated with light, however that does not mean all is lost. Take a look at this link.It was shot near the outer edge of a Yellow zone and things turned out pretty well. I was shooting away from the city center or out to the dark area. Also, see if there is some terrain that you can put between you and the lights. After finding a good location, then -
  1. mount the camera on the tripod, aim it at something, focus to infinity, set the ISO to the lowest you can go then put it into P mode.
  2. You want to adjust both the aperture and shutter speed.
  3. Select the largest aperture (smallest f number) and try say 10 seconds.
  4. Take a look at the image - too dark (go to 15 seconds), or too light (go to say 8 seconds). You can also adjust the aperture as appropriate (or needed) but you will probably stay with the lens wide open.
  5. Wash and repeat, until you get a shot that you are happy with. Then, using that aperture and shutter speed, take 20 or 30 images in quick succession. These are the ones that you will want to stack in order to get a composited result that has the star trails.
Shooting at night is a lot of trial and error.

Thank you and the others for providing so much information.
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