If I take off my ND filter to fly at night/darker sky, is there any reason I need to put the original ring back on (considering there is no filter/plastic/glass on it? I can't think of what purpose it would serve, but I'm also new to the air...
Thanks in advance!
That ring protects the thread not only from foreign objects like dirt, but also from physical damage, like if the ringless barrel were to hit an object.
About 40 years ago, I was getting serious about photography and bought a 35 mm SLR camera. One day, I decided that I wanted to experiment with filters, but couldn’t understand why I couldn’t screw one on, even though I confirmed I had the correct size. Turns out that I had dented the lens barrel ever so slightly, but enough to prevent the filter from screwing on. Ever since I paid $$$ to get it fixed, I have
always kept a filter of some kind on every lens I ever had, even if only a skylight filter. Lesson learned!