One example that comes up frequently is people trying to shoot shots of the moon. They point their camera, in an automatic mode, at a black sky with a small, bright, white moon and find out that the moon is not exposed correctly at all.

The moon is a sun lit object - just like a car sitting on the street at noon - and the exposure should be very close to the same even though the moon is very distant.

So, for ISO 100 the setting would be f16 at 1/100th. Or we could open the aperture two f-stops (f16->f11->f8) and shorten the shutter speed up two stops (1/100th->1/200th ->1/400th) and shoot at:

ISO 100
f8.0
1/400th

Note the exposure data. Guess how I chose these settings???

EXIF ->
ISO 100
f8.0
1/400th

... Just as predicted by the Sunny 16 rule. Now does this seem worthwhile to know??

One example that comes up frequently is people trying to shoot shots of the moon. They point their camera, in an automatic mode, at a black sky with a small, bright, white moon and find out that the moon is not exposed correctly at all.

The moon is a sun lit object - just like a car sitting on the street at noon - and the exposure should be very close to the same even though the moon is very distant.

So, for ISO 100 the setting would be f16 at 1/100th. Or we could open the aperture two f-stops (f16->f11->f8) and shorten the shutter speed up two stops (1/100th->1/200th ->1/400th) and shoot at:

ISO 100
f8.0
1/400th

Note the exposure data. Guess how I chose these settings???

EXIF ->
ISO 100
f8.0
1/400th

... Just as predicted by the Sunny 16 rule. Now does this seem worthwhile to know??