Interesting. How much of the light from the shoot-through is bounced onto the subject from the studio walls, and how much is just lost?.
Almost no light is bounced back in my comparison test.
The umbrella was about 8m from the wall on the left of the subject, and it was a black wall - so, 1 m to subject, then 8m each direction making 16m, and the black wall would only reflect about 5% of the light that reached it, so although in theory
some light must bounce back, in practical terms there would be none from the 60% of the light that passed through the umbrella.
The 40% of the light that bounced back from the umbrella only had to travel about 2m before reaching a white wall, and then 3m back, = 5m, let's assume that about 30% was lost in reflection from the wall, so 70% bounced back, so again virtually no light bounced from the wall would reach the subject. Effectively, no light would bounce off the ceiling either - too high for 3m above the subject, and not white.
This in fact is a shortcoming of my comparison tests - the results from any test are very largely dependent on the shooting environment, and my shooting environment is substantially bigger than most people have. I did think about including some reflectors to simulate a normal-sized home studio but when I thought about it, I had to ask myself "How big is a normal size home studio?" and my conclusion was that it wouldn't work and that I should just explain the principles and advise people to carry out their own tests in their own studio environment, to get results that are relevant to them.
Do you think the results would be the same outdoors? In my (one) outdoor test I got a more contrasty light from the shoot-through than the reflective umbrella, but I readily admit my test was hurried and I need to repeat it.
Tests outdoors should produce very similar results to my own tests, again there would be no reflective surfaces. If you got a more contrasty result in your own tests when using a shoot through umbrella, are you sure that the different umbrellas were at the same effective distance? Size/distance makes an enormous difference. And could it be that your shoot through umbrella doesn't diffuse the light very well?
