Perhaps the most unfortunate thing about photometric lights is that you
are not supposed to use them together with standard lights. According
to the documentation, they do not interact correctly and behave very differently.
I have had some success mixing light types without too much
trouble, but it is not really advisable to do this. You’ll have to try out the
different combinations for yourself to see if they work for you. I have
managed renders using standard, mental ray, and photometric lights
together with expected results, so don’t forget to try!