Multiple Flash Units with 6006

I have a 6006 and SB-26. I would like to add a second Nikon flash

unit to shoot portraits.

1) Will I be able to add a second flash unit and still use TTL?

2) What flash unit would you recommend?

3) Can I use light difusers (such as an umbrella) and still get

accurate exposures via TTL?

1) Yes, if the second flash is attached to an SU-4 wireless TTL slave unit or connected to the camera and your SB-26 using Nikon TTL extension cords.

2) Another SB-26 is the ideal second flash. Other Nikon speedlights with TTL capability (connected as per #1 above) also will work and of course many are smaller, lighter and cheaper than another SB-26.

3) Yes, with the obvious proviso that the flash-to-subject distance needs to be short enough to allow for the significantly reduced light output one gets when using diffusers.

1- Yes you can. You can do it with wires or without wires.

For wired TTL, you need a SC-17 cord (or AS-10) and couple SC-18 or 19 cords.

For wireless solutions, You will need a Nikon SU-4 TTL slave trigging unit to use with your sencond Nikon TTL flash. OR get the SB-50dx or SB-80dx which has the internal built-in SU-4.

2- I highly recommend the SB-80dx. It is a powerful flash , will functions as a wireless TTL and you don't have to spend xtra $$$ for the SU-4.

3- Yes you can. The light output will significantly reduced if you use with light modifier.

There are some limitations on wirless TTL. Be aware!!!.