Center filters

[Ironage]

I am looking for a good filter for my Symmar-s 240mm lens. I think it takes a 86mm front filter which is quite large but would provide some protection for the front element.

What about center filters? What is there advantage, and where do get them?

[Bob Salomon]

Your lens does not need or have a center filter. CF are for the fall-off inherent with wide angle lenses.

What do you want a filter to do?
Eliminate UV?
Warm a scene?
Cool a scene?
Reduce the amount of light overall?
Reduce the amount of light in an area of the scene?
Control reflections and enhance clouds/skies in black and white and color?
Control tones with black and white?
Something else?

[Ironage]

Thanks Bob, that answers my question. I am just looking for a yellow to control sky tones in B&W. I was just thinking that center filters were more common for large format lenses and didn't know.