One thing is I distrust my observations without binoculars (I suppose I classify as middle-aged). I amazed how different my naked eyes misinterpret color, for example, a bird with bright red splotch on the crown (a Redpoll?!?) turns out to be the rusty color of a usual Chipping Sparrow through binocs.
I'm not sure what color I interpret the Great-Crested to be... I think perception can change based on lighting condition, and again, whether it was viewed through binocs or not. You may see gray with the naked eye, a flash of brown when it flies. Through the binocs you may have seen brownish overall, with rufous edging to the rectrices which flashed brighter and translucent rufous when launching itself into the air.