It’s been a while since I’ve done long exposure photography and composites, but my recollection is that excessive noise is a symptom of long exposure and high ISO, and stacking multiple shorter exposures into a composite will significantly reduce the noise of the final photo.
So you’d normally say “that’s too much!” in which case the subject “that” is plural and countable so therefore “much” would be correct.
Otherwise you should say “you have given me too many refried beans!” since the beans are volumetric and not countable entities.