The HiTech P-size ones I have are almost identical to the Cokin ones.
Yes, the Lee are said to be better... except I've heard they have more of a problem with blue skies (where the Cokin Z-Pro/X-Pro apparently outperform them). But the Lees (if you can afford them) are better at producing a moody image

Regarding angle of view - I have used the Cokin P-sized filters on the Pentax SMC-DA 12-24 (which is a 77mm filter). If you hacksaw off all but one of the filter slots on a Cokin P-holder you can get it to work with very little vignetting. To remove the vignetting completely you have to file out the circular aperture in the plastic holder a bit.
Now Cokin do a special wide angle holder which may possibly be better.

So, P size is fine for almost everything Pentax
(Unless you want less magenta and can afford the Cokin Z-Pro or Lee )
Matt

Just an update...
Have got my sticky mits on McBrians O-ME53 and have it fitted on the K10D.
I wear specs (very short sighted + astigmatism) and, yes, there is some vignetting in the top corners, and yes, I need to move my eye fractionally up to get a clear view of the LCD information - but it's not a problem.

Does make a difference - feels more roomy
Matt

As Chris mentioned, water drops are "frozen" because the flash is so much faster than the action and much faster than a shutter (up to 1/20,000s IIRC).

Best bet:
1) Set the camera to manual focus, manual exposure on a tripod
2) Set to something like f/8, 1/125s (aperture is the important one)
3) Turn up the ambient light - get a focus on where the drop will be
4) Turn the ambient light right down
5) Use built in flash

You may need to experiment with reflectors and the like (e.g. bits of white paper or silver kitchen foil) to get some depth to the lighting.

But you should definitely be able to get a half decent shot with that!
...and lots and lots of patience!!

Matt

Very nice results overall

Yes, the Cokin P do have quite a magenta cast. This is particularly evident if you stack 2 or more filters together. Every P size filter I have used has this colour cast (not just Cokin).

The Cokin Z-Pro filters have a lot less magenta tinge to them - probably 1/2 to a 1/3. But then they're much more expensive and right pain to carry around

Matt

This is more a flash question, rather than a macro one

The shutter speed of 1/125s is the fastest the shutter can go and still work with a flash gun. The camera automatically sets this speed to avoid embarrassing mistakes

That said, there is no problem with the flash using a slower shutter speed - it will still synchronise just perfectly.

However, you need to be aware of some background info:
1) Slower shutter speeds mean you need a more stable camera support. For macro this may be a killer

2) Slower shutter speeds effectively let more ambient light in - balancing the flash with the available light.

Point (2) is perhaps the most important. Let me give you an example.
You turn off the flash and meter with the camera. Let's say the exposure is f/8 at 1/15s for the ambient lighting. Now you turn your flash on (and assuming that the "A" setting on the flash is also at f/8 for your current film speed), the shutter speed will be at 1/125 - as you stated.

This means that the flash is 3 stops brighter than the ambient lighting (1/15 - 1/30 - 1/60 - 1/125). This could give you quite a harsh result. However, if you change the shutter speed to 1/30, then the ambient light is underexposed by 1 stop, and the flash will fill in the rest and you'll get a much more "natural" looking shot.

The main thing to remember is this: flash exposure is only governed by the aperture (not the shutter speed!!), while ambient exposure is governed by both aperture and shutter speed.

Hope that helps (and doesn't confuse too much!)
Matt

If you want a brolly as well... then Hama do a nice brolly+mount
http://www.castlecameras.co.uk/product-details.php?pid=31911

The mounting bracket is supplied with the brolly, but can be purchased separately as well:
http://www.castlecameras.co.uk/product-details.php?pid=31909

Has a tripod mount, so I mount the AF360/AF540 on a tripod and use a cheap reflector on the other side - great for head & shoulders studio portraiture

Matt

Lilly - much prefer the colour portrait That's great stuff!

Gartmore,
I have the SMC-F 50/1.7, SMC-F 50/1.4 & SMC-FA 50/1.4 (optically same as SMC-F). SMC-F going to a new home though...

They are definitely different. The f/1.7 has 6 aperture blades - it produces very sharp results when stopped down a touch. However, the f/1.4 is IMHO more pleasing for portraiture. The 8 blades make for lovely bokeh and rendering. However, I'm not sure if the field is as flat as the f/1.7... so I kept the f/1.7 for copy work, but the f/1.4 is the one for portraiture (and flowers too shot around f/2.2 - gorgeous!).

Matt

(sob) I had the chance of one at £399... didn't have the funds at the time
Dang!
Matt

All the Pentax DSLRs have a custom option to "unhook" the autofocus-on-half-press. To AF you either press the "AF" button (if there is one) or the "OK" button on the lower end versions.

Saves a ton of messing about - especially in studio environments. Focus once, and the shoot away!
Matt

There's also www.srbfilm.co.uk - they do Cokin & cheaper compatibles (like the Kood polariser I have).
And http://www.speedgraphic.co.uk/ - they certainly had some great deals on Cokin Z-Pro ND grad sets
Matt