View Full Version : Light distance tests

05-22-2008, 01:28 AM
Conducted with a single craftsman 500w work light and a frost white shower curtain slung between stands. Canon XL1s with zebras set to 85 f-stop set so zebras just appeared on the keylight side of the subject's (my) face. We did this test to try to figure out how to get rid of the "Hotspot" that happens so often in lower budget indie films. I just read somewhere that Hollywood favors larger lights farther from the subject and wanted to find out how much difference distance made. The shower curtain ends up as about a 6'x6' light once the light from the worklight is intercepted. Enjoy!'.jpg'-2'.jpg

Full results at

05-22-2008, 01:53 AM
Have you put on weight? :P


05-22-2008, 02:01 AM
camera puts on 20 lbs...and I'm broad lit ;) I've actually lost 15 pounds :)

05-22-2008, 06:23 AM
That looks great!
How far away is the light, camera and curtain from the subject?

Thanks for posting this.

You look great in a completely platonic kind of mano 'el mano appreciation.

05-22-2008, 07:27 AM
The slate holds your answers ;) First Key is 4' 500watts no diffusion. Second is 10' 500watts, 6x6 diffusion at 2' (8' in front of the light). I used these two images due to their differences. They really show the changes, and are the extremities of the testing we did.

We have 16 other images with all of the steps in between on the website linked above. Along with f-stop numbers and comparative images.

05-22-2008, 11:15 AM
I apologize for not seeing the slate this morning. I was not awake ;) The images on the url that you posted (also didn't see that) are incredible.

Thanks again.

05-22-2008, 02:53 PM
Found it a very en*lightening* ;) test. I was surprised to find that the distance of the diffusion affected the exposure of the key side of the face, not just the position of the light. I knew the diffusion would take away a stop or two of light, but I didn't think it would vary as we moved it. That was kinda neat.

Physics make me happy :)