Right. Will try to keep this straightforward.
Firstly, now that I've decided to try out Raw Therapee instead of purchasing DxO (thanks for the advice), I've saved nearly 200 British pounds (this is logical thinking, isn't it?). So I can spend it on other things.
Based on what I read elsewhere, I think I could mount GNDs onto the Tokina 11-16 and not have a major vignetting problem. But to do so would want to get the Lee Wide Angle Adaptor Ring. First question - Anyone else using it and does it work for you?
But, then we start looking at the filters. The following are quotes from the website of my usual supplier (who usually copies and pastes descriptions from the manufacturer's site). And these confuse me (which is not hard to do).
"The soft edge is recommended for wide angle lenses and the hard edge is recommended for normal and longer lenses."
"... hard filters are used in particular when using 35mm cameras, digital SLR including full frame and medium format cameras ... and the soft filters are used in particular with large format cameras."
Now, whilst perhaps not totally contradictory, these are, I hope you'll agree, confusing. I thought I understood hard and soft in the context of GNDs, i.e. straight line or not. Seems Lee has a different meaning ... or do they!?
I've got a Cokin P system at the moment and am persuaded to aspire to a Lee system (mainly because I want to use GNDs on the Tokina).
So, on my Canon 40D with my Tokina 11-16 + the 17-85 and 70-200 - What do I go for? Hard or Soft GNDs?