Hi all

I have a shoot arranged for next week and I think I have a pretty good idea of how to achieve what I want, but I'd appreciate any input and ideas that will help make it work. Please excuse the long description, but I hope this will make it easier to provide input.

This is a mock up of the shot.



But now imagine that the person at the front is actually female, wearing heels and with bare legs that show a tattoo on her right upper thigh. The thing she's holding is a whip (orange) which trails onto the ground front right. From the end of the whip a trail of fire extends out and around the bike (the red line). The jacket was just a marker, ignore it. Yes it's over the top :-). I want a low key, dark and slightly fantasy look (i think). Dark is going to be a bit of a necessity if I'm going to have the fire trail as this requires a long exposure. So timing will be an hour before sunset into darkness.
Lens is 70-200 at approx 80mm to get foreshortening effect and bring legs and bike closer together. Camera to legs about 3-4m and legs to bike roughly 3-4m more.
My set up process is going to be:
Get composition sorted
Set aperture approx f16 so legs are in focus and bike out of focus.
Set shutter speed to get required level of ambient light (low key)
Set up one snooted flash camera right pointed at the models right thigh.
Set another flash camera left pointed at the bike.
Fire away adjusting flash power until I get something with model and bike both lit but background suitably dark and dirty.

Possible problems might be getting enough light on the bike at that distance. In which case I might try painting it with a torch.
I may also struggle to get the balance right so I may shoot at various powers for legs and at various powers for bike and choose the best pair to combine later.

The final thing to add is the fire trail. This will probably have to be done after the sun is down and then this shot added to the others to give the final composite. I will try doing it in one shot with lights on model and bike, but I'm not sure how this will go. It's going to be tricky getting it right with the flashes and a long exposure, plus me entering stage right with a flame after the flashes have fired. A realistic composite is often hard to achieve though, even using gels too give a light that matches the flame.

So, has anyone got any experience that will help me out on this. As you can see I've had a think about it, but not actually had a go yet and I'm pretty new to off camera flash work. So I'd welcome any ideas/hints etc from more experienced people.