Lock exposure,using back button focusing.

[tonyq]

I have set my Canon 600D camera up with Back Button Focusing using the * button. What I cannot get my head around is how I now Lock the Exposure. I presume the shutter button still sets the exposure, but how do I now lock the exposure? There is probably a simple answer but I cannot seem able to find it.

 

[jm2]

Half press of the shutter will lock exposure, in AV & Tv mode.

 

[Canon Bob]

It's not the world's best solution for bodies lacking a dedicated AF-on button. Using the * to focus means that you've got to half press and hold the shutter to lock exposure.
My approach would be to shoot in manual mode. Meter the shot and set you exposure parameters and then focus and shoot as required with the * and shutter button.

Bob