I used my EDC flashlight as a "fill light" the other night
It was a Sunwayman V10R TI flashlight, which has infinitely variable brightness, and I just dialed it up enough to get the reflectors on the side of a police vehicle to light up a little bit (I was at something like 1/50 f2.8 12800iso, so didnt need much light at all, and the constant light helped focus too)
I have also used my Maxabeam to fill shadows at a fire scene at night (50ish metres away from the roadblock, but that is a kinda specialty searchlight, not a normal carry light.
Some of the new flashlights are amazing In terms of output, and colour.
I have a light that is 1000 lumens has a very floody even beam, and is around 4500k
I have used it for photos, normally just to fill shadows or light up reflectors to help focus in the dark.
I have used it as a primary light source for one job i remember though, bounced into a big industrial bin to illuminate a "dumpster diver"
Have a look at Candlepowerforums - there is a lot of information there, and the crew are just as helpful and friendly as POTN
Personally I would look for an infinitely variable output light, as you can then easily dial the light level up to what you need