black flash will never have as good of flash distance as red flash or white flash. it's the price you pay for being undetectable. I don't really care so much about black flash. I used to think it was a must. deer, for me, aren't spooked by cams at all, regardless. so the black flash is more for keeping cams undetectable from people who might be in the area in lower light times, and might see a flash. but I always go out of my way to put my cams in the most remote areas where they would see no people. for that reason, I don't worry too much anymore with black flash and prefer red flash.
I've never paid attention to the sharpness, to see how the differences may vary. I know my spypoint is black flash, and it has brutal night images and videos.