I am finding DROID returns the incorrect result occasionally and seems to return a hit to a pattern too early. I have a set of TIFF images which under DROID 6.8.0 all identify as fmt/353, but under 6.9.3 a few of them return a positive identification for fmt/202. In looking at the signature for the Nikon format, there is no pattern which completely matches my samples, only partially.
