Despite having 2 77mm B+W filters for my 10-20 and 70-200 VR. I do have a crappy filter as I mentioned earlier.
I tried to take two test shots earlier. Honestly I can't notice the differece in image quality with the filter on or off. For those of you who noticed the differece, can you try to tell me what to look for? Is it sharpness (shouldn't be the case...), or less color contrast (didn't notice that...)?
I used to use a filter to protect my lenses when I was using my own gear for my day job as a timber industry geologist. But then I got wise and stopped carrying SLR gear altogether, particularly my own gear, because a damaged front element is the least of my worries. My field work usually involves wading up and down high gradient streams and slopes where a large camera is a hassle and prone to getting busted up. So I now just carry a little Canon G3 in my field vest -- it seems to always have a film of mud and fir needles stuck to the lens!
For non work-related photography with my Nikon gear, I never use a UV filter unless I'm on a small boat and the lens is exposed to salt water.
Years ago (film Nikon days) I used either a skylight or UV filter on all my lens as a form of protection. I read many professional and advanced amateurs (including many on FM) never use filters. I still use them but I am questioning my on decision to do so. What's interesting is that one consideration is that no matter how good the filter is, it's still another piece of glass for light to travel through and potentially degrade the image. I have taken a number of photographs of birds outside my kitchen window using a D70 and now a D200 on a Gitzo 1325/Markins M20, with the 70-200 AFS VR lens, both JPG and RAW. Many of these were shot through an insulated or "double pane" kitchen window that's about 22 years old and the resultls are spectacular - even in enlargements they don't look any different from those shot with the window open. I would think that double piece of window glass would cause noticeable image quality loss. I do keep that one window very clean! The filters I have are Nikon or Heliopan. Since I have them I will continue to use them, but knowing what I do now I would not purchase them if I had none. YMMV.
