Mine has arrived today and I've been trying to get to grips with it. At its palest setting I reckon it is losing 1.7 stops of light rather than 2, which is fine, but I am struggling to get 8 stops of filtration without running into problems of edge/corner darkening at 24mm and even 35mm on my 5D2, and stopping down does not seem to help. At 100mm on my 1D3 there does not seem to be such a problem.
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Mine also arrived this morning and I found the same thing
The cross pattern starts to intrude unacceptably from about four stops of light reduction. That's on a full-frame Canon 5D2 with 17-40L at 17mm. You see it most at ultra-wide but it's not acceptable at any focal length, and anyway, I want to use this thing with wide-angles. However, it's worse than that - I'm also getting quite bad flare and softening with longer lenses
The good news is that I also got another ND filter today - the LightCraft X500 which is a fixed nine stops multi-coated ND, and that is
excellent all round, and
great value at £58 in 77mm (only size ATM)
I have just compared side by side the new Light Craft Workshop Fader-ND MkII, with the same company's MC ND-500 (x500 = nine stops, I reckon it's about 8.5), and also the uncoated B+W 110 (ten-stops, nearer 10.5 I think) and for good measure also a top of the range Tiffen HT 1.2 which is a multi-coated four stops ND.
The fader MkII is nice and neutral in colour, the best I've tried for that, but that dark cross shape - the result of the two polarising filters rotating against each other - begins to show itself after about four stops of darkening ND effect and then just gets worse.
For colour, the LCW X500 was very slightly blue, but it's very slight. I wouldn't even bother to white balance it normally. (Colour is similar to the Lee Big Stopper, from memory.) The B+W is well known to be a bit warm/orange, to the extent that it needs custom WB. The Tiffen is a bit green - marginal on whether that needs custom WB as a matter of course IMO.
I then pointed all the filters at a bright desk lamp to see how they handled a bit of flare provocation. The LCW Fader MkII was by far the worst, not good at all, but the best was its sister product, the multi-coated X500 which was really very good. Next was the multi-coated Tiffen which was more than acceptable, and the uncoated B+W which flared quite a bit and emphasised ghosts too.
Final test was for sharpness, which really only shows up on longer lenses, which magnify any imperfections as they only look through a small central area of the filter. Camera was a 5D2 with 70-200L 4 IS with a Kenko Pro 1.4x telecon - at 280mm the longest combo I've got, all at f/8.
In terms of sharpness, all these filters performed very well - except the Fader. It was bad, but then it is two filters in one, plus two polarising layers inbetween. When I did the same test at 24mm I couldn't really detect any softening.
I also noticed some slight residual polarising effect with the Fader, as it was rotated.
I guess the idea of the Fader is just too good to be true - 2-8 stops variable ND. I can't recommend it on this showing. What is still puzzling me is that when I tried the MkI Fader at the Focus show recently, I didn't notice it being anything like as poor as this - I wouldn't have ordered one if I'd noticed these problems. I don't know what has gone on in the manufacture between the MkI and MkII, but this one is going back.
On the other hand, the LCW X500 (*) is really excellent - the best ND filter I've tried by a good margin, and also the cheapest. It's only available from here I think, and only in 77mm for now
http://www.premier-ink.co.uk/photog...raft-workshop-77mm-nd500mc-filter-p-2927.html It doesn't have a front thread so you can't fit a lens cap with it on, but that also means it is super-slim so there's a good chance you could also screw it into the front of another filter and still get a very wide angle view before it vignettes.
Edit: * this is the X500 filter that Peter refers to in the post above
Double edit: the polarising effect with the Fader referred to above is not just 'residual' but pretty much like a regular polariser as far as I can tell.