# Always Look On The Bright Side…

…at least when you are shooting the moon. Like in this shot, made at 3AM right outside my front door:

(1/80 sec, f/10, ISO800)

For me, it is another chance to point out to you how bright the moon is. About as bright as the earth on a sunny day. Because when you see the moon it is experiencing just that: a sunny day.

For a starry night, however, you need a much longer exposure. Many stops difference. You show the stars, or you show the moon; never the two together. A rough calculation gives me:

• Moon: 400 ISO, 1/400 second, f/16 (“Sunny sixteen”) or lower (last night: f/8);
• Stars: 3200 ISO, f/1.4, 20 seconds.

So how many stops difference between those two?

• ISO: 400 to 3200 is 3 stops.
• Shutter: 1/400 to 20 seconds is around 13 stops.
• Aperture: f/8 to f/1.4 is 5 stops.

So the total difference in brightness is around 3+13+5 = 21 stops!

So until the dynamic range of our sensors and cameras is 21+ stops, you cannot show the moon and the stars in one picture. You would have to use HDR, or just combine a star picture with  moon picture in Photoshop.