Sunny 16, Looney 11, Starry ???

<p >I've done some searching and haven't been able to find a consistent answer so I'm hoping someone can help me out.</p>

<p >I realize that conditions can be highly variable, but taking the most general settings (clear night, stars visble, no moon) is there a exposure rule for star trails that's similar to the Sunny 16/Looney 11 rules? Or if not, is there an aperture/shutter/ISO combination that works for most occasions?</p>

<p >BTW,</p>

<p >I'm using a D700. What's the max time that I can leave the shutter open without getting negative results from amp glow?</p>

<p >Also, sice the use of Noise Reduction essentially doubles the amount of time needed to take a photo, can I turn Noise Reduction off and then take a lens cap photo using the same exposure settings later on to use for noise subtraction?</p>

<p >Example, say I take 4 photos each at f/8, 15min, ISO100, all with NR off. Can I shoot a 5th photo with the lens cap on using the same f/8-15-100 exposure and load it into Capture NX to use as a noise reduction reference pic for the first 4 photos?</p>

<p>Have you done any research on image stacking for star trails? Might solve the whole dark frame issue by rendering it moot! :)</p>

 

Since stars are effectively point light sources, the exposure needed depends on the size of your lens opening, not the f-number. For a star, you collect the same amount of light (and need the same exposure) with a 200mm lens at f/8 as you do with a 35mm lens at f/1.4. (Of course, if you have some of the surrounding landscape in the picture too, the exposure needed for that does vary with f-number.)

<p>Take a look at here.<br>

http://www.photo.net/casual-conversations-forum/00SzJg</p>

<p>ISO1600, 477 stacked images, over 4 hours.</p>

<p>Normal photographic rules twist in the darkness. ;)<br>

Seriously though, I don't think there's a consistent answer to your question. Only starting points for different methods.</p>

<p>Actually, take a Google at Fred Parker's Ultimate Exposure Calculator. It has exposures for varisou amounts of night light... full moon in summer, full moon on snow, etc. It's actually a spreadsheet you download for free, and I've found it extremely accurate.</p>

<p>The star trails' length can be calced pretty easily. A star will rotate 360d in 24 hours, or 15d per hour, or 5d in 20 minutes. Five degrees is enough to see the trail, but it's not a very long trail. So then you can go to Fred Parker's calculator, find a night scene that has the amount of light that will give you a good exposure over the time that it takes to form a decent start trail</p>

<p>I seem to recall that the looney 11 rule is f11 and 1/ISO in DAYS, for properly exposing a scene lit by the moon. Which makes sense given how much less light the moon casts compared to the sun.</p>

<p>So if you're at ISO 100, this would be f11 and 1/100 day which is 86,400s/day/100 = 864 s = 14.4 min. I usu. shoot wide open, say at f2.8, or 4 stops which is 0.9 min or 54 s.</p>

<p>And, as others have said, to get the moon right, just shoot it at sunny 16.</p>

<p>this sounds like fun,how can I do this with my nikon d7000.I have two lens,one a nikkor 70-300mm vr and a nikkor 18-105 mm vr.Which would be the best to use and at what settings would you recommend ?thanks</p>

<blockquote>

<p>I seem to recall that the looney 11 rule is f11 and 1/ISO in DAYS, for properly exposing a scene lit by the moon. Which makes sense given how much less light the moon casts compared to the sun.</p>

</blockquote>

<p>The amount of light reflected off of the moon is about 1/1,000,000 of that we get directly from the sun. This is twenty stops.</p>

<p>Therefore on a clear night with a full moon, what would be a sunny 16 exposure in daylight e.g. ISO 100, f16, 1/125 will nees a shutter speed of about two hours assuming ISO and aperture stay the same. This is for scenes lit by the noonlight and not of the moon itself.</p>