Originally posted by LFLee
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I would like to know how can I get a shot with a clear moon (where you can see the details and not wash out like this one), in a long exposure shot like this?....
Lee
Your shot was ISO 100 at maybe 8sec, f/8. Others have said the moon should be exposed for 1/30 sec to freeze it - let's call it 1/16 sec because it is small in your photo.
So we have to move from an 8 sec exposure to a 1/16 sec exposure. In speed stops that is:
8-4-2-1-1/2-1/4-1/8-1/16 minus seven stops total decrease. These 7 decreased stops must be compensated by increased stops elsewhere;
ISO can be increased maybe 5 stops 100-200-400-800-1600-3200 without too much noise.
The remaining 2 stops can be gained by f-stops: 8-5.6-4.
An ISO 3200, f:4, 1/16sec exposure of the city and will be the same as in your original photo because there is no net stop change. But the moon will still be as overexposed as it was in the original, just not blurred. The moon's proper ISO 100 exposure is about 1/100 at f:16.& the number of stops needed for a neutral filter to dim it can be calculated by counting stops from the original exposure 8 at f/8 to 1/00 at f/16.
8sec at f:16 is the same as 4sec at f:8 so the number of stops from 4sec to 1/00sec is found by counting the sequence of divides by two:
4-2-1-1/2-1/4/-1/8-1/16-1/32-1/64-1/128 (9 stops)
So you'll need to have about a 9 stop ND filter in front of the moon during the exposure to dim its image enough to see detail.