Hey Vic
I think the choice is whether you want to place the subjects in their environment, or impress a context upon them. The first being available light, with possibly some fill. The second of course is shooting the flash.
The advantages of flash, for me, would be the abilityto manage the ambient light with normal film and development. Dialing up enough flash ( not much ) to overcome the overhead lights, and hold some tone in the background and windows and stuff...
I'd use whatever magic brew you used for the pictures on your website, and add just a little bit of flash.
They are a little unwieldy, but Chimera makes a couple small softboxes (
http://www.chimeralighting.com/products/specs_lightbanks.cfm?product=mm) that are really handy for this sort of thing. The smaller one ( 12 x 16 ), with part of it over the lens, is not an unpleasant way to work.
Or you could just expose for a pleasant environment and add some flash to pick out the folks. But I wouldn't go far from the look of your New York pictures.
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