photographic conundrum

[FrankS]

Originally Posted by nikon_sam

Let me throw this into the mix...

From what I have read you are lighting and shooting a subject and then moving back twice the distance and getting the same exposure when you think you should have less light...The subject to light distance is the same just the camera to subject has changed...If you shoot with the same lens the subject will be smaller but still lit the same.
Let's say you move back 100' with the same lens the subject will be lit properly you just might not be able to tell...Now put a tele lens on the camera and bring that sucker in and you're back to square one.
Now if the light source is mounted on the camera this does not apply...

That's correct.

[Bryce]

Frank-
You've caused a great deal of trouble today, I'm sure glad it is over. Like all things that take effort to take in, your post on reciprocity failure caused me to learn a little more about something that has caused me a ton of frustration, the multiple flash underexposure problem.
I can't thank you enough!
So when are you going to come up with another one?

[FrankS]

Thanks Bryce!

Okay, 2 trains leave the same station travelling in opposit directions....

[Ronald M]

Because the law refers to a point light source or reflected body.

A subject is not a point source.

[FrankS]

Anyone have another "photographic problem" to post?