Power supply to run camera and 555 timer

I'm looking for ideas for building a power supply (out of batteries) bank that will run a 555 timer circuit and a Kodak Digital camera. The camera takes a 3vdc supply. I have a number of 555 timers but I think they take at least 5 volts to work.

For the camera, I'm thinking of building a circuit that will activate the focus button, then a couple seconds later activate the trigger.

I'd like to use the same power supply but have it as efficient as possible. What's the most efficient way of using a 6V gellcell battery to supply both 3vdc camera and 5vdc 555 timer trigger?

Thanks