If Dino will allow it, try using a flashlight instead of flash. A steady source of light is less disturbing that sudden intense flashes of light and should prevent startling cats. Just be careful of the kittens' eyes. You can also use desklamps if you have one.
Dr. Seuss~DLH (brother's cat)~June 2007-
Misty~DSH (my cat & Mooby's mom)-?- Sept. 15, 2014
MooBoots(Mooby) ~ DMH(Mom's cat)~July 21, 2008-
Sunshine~ Golden retriever X white german sheperd (Dad's dog)~October 24, 2008-