Quote Originally Posted by Drew Wiley View Post
Significant falloff is an optical fact with these wide angle lenses, Ed. YOU might not feel the need for a center filter, but someone else might. There is a reason they make, recommend, and sell them, you know. If you personally happen to like darkening toward the corners, that's fine. It is a creative option. Sometimes
you can dodge/burn to correct that; sometimes, you can't due to excessive loss of information. Maybe the detail in deep shadows won't be sufficient, maybe
there will be an unbalanced color shift in a color neg film, or just outright excessive contrast in a chrome affecting printing or reproduction.
And you can't burn and dodge a chrome.

Also, the falloff starts after about the first 30% of the coverage of the lens. So it is basically always there. A center filter does not eliminate the falloff but it does even it out and minimizes it.