Because to make black and white prints properly you need dedicated black and white inks (usually various greys). A regular printer will try and make the shades of grey using the cyan/magenta/yellow inks which will nearly always lead to a colour cast. Without buying a new printer there's probably not a lot you can do I'm afraid...

Cool, I'll try that as my back up then

I've parked there before so that's where I'll be heading first, if it's full though that means parking at the Harlequin and a long walk...

I'm not sure what they're referring to on the website but the "slim" holder only has one slot.

The price difference between the P and Z-Pro systems is partly down to size but also because of economies of scale: Cokin will produce thousands of P filters and kits for every hundred Z-Pro kits so there is a difference in costs for manufacture, distribution, etc. As far as I know the quality is the same with both systems.

The quote from Cokin regarding 19mm lenses is assuming the lens is used on a 35mm camera. At 12mm the 12-24 is about the same angle of view as a 18mm lens on film, hence a very slight vignetting at this widest point that has disappeared by 14mm.

As for a CPL, I wouldn't bother with one for the 12-24. For a CPL to work properly it needs to be at 90 degrees to the light source (the Sun usually). At 12mm you will have an angle of view greater than 90 degrees so the effects of a CPL will never be even across the frame and your skies will have different colours on one side compared to the other. The only filters I ever use on the 12-24 are ND Grads (which are very useful!), although I have a couple of smaller screw-in CPLs for my longer lenses.

Hope that helps!

I'm planning on popping over in the morning, probably leave here about 10-ish so should be there around 11 (depending on where I get parked once in Watford)

The best prices I found were actually from SpeedGraphic. I bought a Cokin P ND Graduated Kit for £39.95 (three grades of Grad ND filters plus a regular 3 slot holder) and a Cokin P Wide-Angle Holder for £9.90 at the same time. I then bought Kood adapter rings for each size of lens from 7dayshop (prices from £2.99 - £3.39 each) as they were cheaper than the genuine Cokin ones.

As Jon says above, I too only use the P filters directly on the 12-24, ie with no other filters attached.

Mine too!

It looks to me like the Tokina is pulling *slightly* more detail from the scene (looking at the brass hook in the lower right of the first crop and the wood grain next to the window frame on the second) but there's barely anything in it and I think I actually prefer the overall rendering of the Pentax lens from the two uncropped examples.

When faced with straight lines though the DA18-55 can be prone to a bit of barrel distortion whereas I always thought the greatest strength of my old Tokina was the lack of any distortion. Still, it shows how far zoom lens design has come over the years - and this performance from a "mere" kit lens to boot!

I use the Cokin P filters on my 12-24 and there is very slight vignetting from 12-14mm but nothing from 15-24mm. Cokin make a special slim holder which I use on the 12-24 (only has one slot) whereas I use a regular three-slot holder on my other lenses.

Well at the moment I'm guaranteed a podium place