Clear sky for a moon shot.

Not many planes flying at NAS Pensacola today. Taken with the Sigma 70-200mm handheld. 100% Crops. Can't wait until I get the 2x teleconverter. Should be on it's way.

Shutter Speed - 1/1600 sec.
Aperture - F/4.5
ISO - 400
Focal Length - 200mm

I like the first one, Nice shot. 2nd one seems a little blown to me.

drparker wrote in post #2198554
I like the first one, Nice shot. 2nd one seems a little blown to me.

Thanks. I agree on the 2nd one. A little more PS'ing.

Nice. I like the first one better.

The moon is an object with reflectivity close to that of an 18% gray card, illuminated by sunlight. Therefore, theory says that proper exposure should be around 1/ISO @ f/16 (or equivalent combinations of shutter speed and aperture). For various reasons, when photographing the moon it's generally best to modify this famous "Sunny f/16 Rule" somewhat, to roughly "Sunny f/11."

Your first shot obeys this rule pretty well. 1/1600 sec. @ f/4.5, is equal to 1/800 sec. @ f/6.3, or 1/400 sec. @ f/9. (In each case, every time we go up one stop with one variable, we go down one stop with the other, so overall exposure remains unchanged.)

You were shooting at ISO 400, so our "Sunny f/11" rules says proper exposure should be right around 1/400 sec. @ f/11. Your 1/400 sec. @ f/9 is within 2/3 of a stop of that. Given that this is just a general guideline, and not necessarily an absolutely precise law, 2/3 of a stop is close enough. That's why your first photo looks pretty good. You nailed the exposure, or at least came close enough so as not to matter.

Your second shot was taken at 1/60 sec. @ f/5.6, using ISO 200. 1/60 sec. @ f/5.6 is the same exposure as 1/30 sec. @ f/8, or 1/15 sec. @ f/11. (Again, as we go up one stop with one of the settings, we go down a corresponding stop with the other.)

Since our "Sunny f/11" rule says that at ISO 200, proper exposure would be around 1/200 sec. @ f/11, and you used the equivalent of 1/15 sec. @ f/11, one would expect your photo to be grossly overexposed. Overexposed by around 3 1/2 stops, more or less. And sure enough, the photo is grossly overexposed.

I apologize if it sounds like I'm lecturing you. For all I know, you may already be well aware of the Sunny f/16 rule, of the need to open up about a stop beyond what the rule indicates if your subject is the moon, and of how 1/60 @ f/5.6 equals 1/15 @ f/11.

But I'm sure that some of the people reading this post are not aware of such things, so I figured it best to err on the side of too much explanation, rather than too little.

One final thought -

Some people will undoubtedly figure, "This is all too technical. F/11, equivalent exposures, opening up a stop, etc. I hate math. I'm just going to let my camera choose the right exposure."

The problem with this is that unless one is using a very long lens (several times longer than 200mm), the moon will take up only a small portion of the frame. Therefore, your camera will see a small, bright ball, against a large, dark background. (I'm assuming the photo's being taken at night. Obviously, in daytime, the sky tends not to be dark. But most photos of the moon are taken at night, when the sky is dark.)

Now, some cameras use really clever algorithms to determine proper exposure, and will "know" to expose for the small, bright ball, and ignore the large, dark background.

But in many cases, the camera won't be so clever, and instead it'll be "tricked" by all that dark sky into overexposing the moon.

This is why, in general, one is usually better off using manual exposure when photographing the moon, and not just trusting the camera to get it right.

(Notice to nitpickers - Yes, I left out all sorts of details. My intention wasn't to write "The Dummy's Guide to Lunar Photography," nor even "The Zone System for 21st Century Digital Astrophotographers.")