The debate about whether to use a filter or not is one that’s filled many online forum pages, none in which I have participated. Shooting in this part of the world, where maritime exhaust, vehicle pollution, factory emissions, construction dust, and smoke from illegal land clearing constantly fill the air, use of a filter is a given for me.
In most circumstances. My now-departed 280mm f/4 APO-Telyt-R had its own front protection element. And now many lenses come with fluorine coating on the front, which obviates any dire need for a filter.
Ever since Nikon’s 300mm f/4 phase fresnel lens came out I’ve been a regular user of it, though I’ve bought and sold a few copies over the years. Call it love/hate due to extremes in its positive and negative attributes. I’ve always used it without the hood and with a filter.
An outing yesterday changed that. My current copy seemed to render slightly fewer details than previous copies, so I decided to try it with the hood and without a filter. What a difference. There were the details again, plus some.
So I guess filter use, even in extreme environmental conditions, varies not only from one person to the next, but also from one lens to the next. Forty years of shooting, still learning, and very grateful for the privilege.