Division of Long exp by short exp

[Drew Wiley]

Tourists in the monuments? Oh, that's an easy problem to fix. Bring along a pet skunk.

[RSalles]

Bonjour Peter,

Two years ago I've made a series of divided exposures in my house studio, alternating exposures only with speedlights, SL + painting light and candles lights + SL.
My calc ended up giving me 1/2 or 2/3 more light then the simple math. At that time, I remember had used my digital camera to chech exposures read by the flash meter, and adjusting it accordingly. Now I have a flash meter that makes the calc for me with cumulative metering readings, but still have the option to use my "electronic polaroid" check just to make sure the film will not come under or over-exposed.

Ex.: of shot, that I made:

4x5_2014-3886-89 by Renato Salles, no Flickr

with candles

Sinar F2, Rodenstock Sinaron 5.6/210 at f22, 4x5 Shanghai GP3 ISO80, Rodinal 1:150 in stand 2hs..
Two exposures with the shutter open: first with (3) speedlights and the candles lights off, and the second only with the candles lights for 10s.
Negative scanned with a FF DSLR in 4 passes, stitched in PS.

Cheers,

Renato