As long as you have your electric focusser hooked up to your pc or laptop I see no reason why Focus Max wouldn't work with a DSLR. After all it is your focusser not your camera that brings stars in to focus.
As it is freeware, assuming you have Maxim, why not download it, give it a go and report back.
I would give it a go but all my V curves are setup for my ccd and the idea of recording new ones for a DSLR and then rerecording ones for my ccd doesn't appeal to me, if it aint broke don't fix it. Besides with Sydney's cloud the way it has been we will be up to Maxim version 23 before I get to it
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Wayne