I bought a bag full of old camera stuff for a whopping $20, mainly for the couple of MF Minolta lenses, and among all the miscellaneous stuff there was a Hoya 67mm NDX4 filter in perfect shape.
So, what do I use it for
? I know the idea is to lower the light by 2 stops, but I can't think of many scenarios other than running water in bright light. I wish it was a GND. Anyway, any cool ways to use this ?

