Tag Archives: flash

Backlighting transparent objects with strobe

As a film shooter, I can’t just make a rough guess at flash exposure and then dial it in from there by test shots. Well, I can, but the turnaround time is a little high using regular film and doing it with Fuji pack film like the commercial shooters used to do isn’t cheap even if you do have a camera which accepts a Polaroid back (I don’t).

This is why, when I splashed out and bought a handheld meter, I made sure it also had flash metering capability. This makes it very easy to get a good exposure for reflective subjects, just point the meter back at the flash and have at it.

But it wasn’t at all clear how this would translate to subjects which allow light to pass through. Would metering as normal produce a transmissive object with the right amount of “glow”?

So as any good science-and-logic oriented person would do, I performed an experiment, with 5 shots bracketed at -2 through +2 stops from a normal meter reading, in 1 stop intervals. The flash was aimed from behind and to one side of a clear lead crystal candlestick, and goboed to prevent any output directly striking the lens.

The results were as follows, all shots being straight “proof scans” from the negative (made through the clear binder sleeve, so disregard any hairs or dust) with standard setting of white and black points for the film and development used; my normal method of proofing a complete roll.

The shot as metered (center) has a very good overall “glow”, but depending on intent -1 would also work and +1 might be OK for some cases. This is good enough to satisfy me that I can get the result I’d like. I haven’t tried lighting from beneath a clear object but this would obviously be a good point to start from as it’s the same basic principle.

A more complete shot would usually also include some degree of lighting to fill in the shadows, of course.