Roger I use Efke 50PL (4x5) developed in Hypercat, Efke 50 has a very different look to others film especially in pyro, where it really shines in my opinion. I also use Pan F these film have a very different look, Pan F has more inherent contrast and creates a cooler look (don't know how else to describe it). Adding a ND Filter to an uncoated lens adds an additional glass surface not so good. And to quote you "Pan X did, not with the same look granted, but finer grain." Well I don't have a problem with grain I love it in fact, but I am after a certain look that I get with a certain film. I am also sure that I will be able to recreate that look with other films, I just have to experiment some.