Are there any markings on the DK-17C eyepieces to identify what they are? I think I have mixed up a 17C with the plain 17 and was trying to find a way to be sure which is which, short of putting it on the camera looking through it. I've tried that and am not noticing any difference.
Apparently the plain DK-17 has no markings on it. However once the DK-17C's rubber ring is removed (very easy and not harmful) it is marked in easy to read plain white letters on the front of the metal ring.
If you wear glasses, it lets you make an adjustment beyond the capabilifies of the built-in diopter adjestment, and still see without your glasses. If you just want a larger view in the viewfinder, get the DK-17M.
I do wear glasses but I don't use them when looking through the viewfinder (they cause too many reflections). I have to turn the dioptre adjuster to full plus though before the viewfinder comes into focus.
Presumably I wouldn't need full plus on the adjuster if I fitted a 17C?