Quote:
Originally posted by monica
You cannot get more light on your background by moving the light away from the background. The further the light is, the less light you're going to get.
The reason you are seeing an improvement at all is because you are giving the model less light. This brings the model down closer to the amount of light hitting the background (virtually none). The light hitting the background is so isignificant that moving the light back hardly changes it at all, but the light hitting the model is so much brighter, that you will see quite a difference there by moving the light back.
Here is a quote:
"Illumination from a light source reduces considerably over distance. The relationship between illumination and distance from source is explained by the "Inverse square law of illumination". For example if you double the distance then the illumination is reduced to a quarter of its original value."
From the following website:
http://www.ted.photographer.org.uk/p...e_lighting.htm
So say your background is F4, mainly because it's quite dark. Your model is F16. Huge ratio. If you move the light back, your background will probably stay around F4, but your model will move to a larger aperture at about F11 or even F8. This way, you shrink the ratio, and now your film will see it.
If you're using color slide film, you'll still be out of luck, but color neg has a pretty good latitude, black and white even more.
And then if you're using digital, all the better.
|
Take a flashlight, hold it 6" away from a
peice of paper. Now move it back 18".
Seems obvious to me.
Of course, I mostly do 3D graphics with radiosity, which tends to be a bit different then traditional photography, mainly much much harder to get lighting done 'correctly'.