Hi Peter
Have a look at "Images Plus" by Mike Unsold.
He recently began to give it away for free.
http://www.mlunsold.com/ILOrdering.html
I believe it is quite strong in the use of DSLRs although I have not used it recently for DSLR's, so I don't know what up-to-date Canon DSLR's it can handle.
Cheers
Dennis