These are copies of 35mm slides. (Made with the slide duplicator here) https://photography-on-the.net/forum/showthread.php?t=58609
We needed a shot that illustrated many products that could be made from the bypoducts of coal-gassification. Seemed a pretty dry subject so we decided to take it outside. This shot used a 750 watt quartz fill light, but similar results could be had using a flash with a warming filter. The trick is to get the light far enough away so the light fall-off is minimized.
"Standard" f-stops: f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128, etc.
EDIT: "light fall-off is minimized" What I mean is, if the light is 2.8' away, the intensity changes 1 stop between 2'-2.8' & 1 stop between 2.8' to 4'. Not much "depth-of-light"?
But at 35', the intensity changes 1 stop between 32'-45' & 1 stop between 22' to 32'. Much better, no?
This should clarify that concept...
Here's something that will help you figure light fall-off in your head:
The difference between a light at 2.8 feet & the same light at 4 feet is 1 stop.
Same for 8 feet to 11 feet.
Same for 16 feet to 22 feet.
Do you see where the difference between those numbers come from? They come from the The Rule of Inverse Squares & also correspond with f-stop numbers.
4 to 5.6 to 8 to 11 to 16 to 22 to 32 to 45; there's one stop difference in fall-off between them.
So, if you're 6' from the subject using a fixed output flash & you want to use f/4 but the fixed flash output requires a setting of f/5.6, then just back up to 8' & zoom in a bit. (Or you could just ND gell the flash.)
If you're shooting something at a great distance, like sports, you could choose a setting for 45' & everything within 32' & 60' would be within one stop, which can easily (usually) be fixed in RAW processing. I've done that with football & hockey & it works well.
My favorite location flash, & there are a lot of links in here:
Simple "every-day-emergency" location lighting
Curtis has a great thread on FLASH PHOTOGRAPHY 101 – A BEGINNER’S GUIDE that includes an example. Check it out.
The background math, for the Measurebaters among us: Digital Photography One on One: Episode 59: Inverse Square Law
More manual & auto flash info here: Settings?? Help Needed!
Low cost off camera flash tutorial for beginners
Easy tip to find your starting exposure: Guide Number: Your Free Flash Meter
How to Shoot Flash Into a Sunset - Strobist
The first shot is sort of what we had in mind (but we shot it later). Then I saw the sailboat coming & there was a mad scramble to set up for it. (The assistant had her feet in the water while she held the sail.) Another happy accident happened, too. A skin diver came out of the water & we borrowed him for another variation.
So the moral of the story is, when you've "got the shot", don't stop. Look around & keep shooting. Chances are that you'll have some happy accidents, too!