10 stop ND filter

This is another filter post... I figure tis lens related so it's here as there is no accessories section... If the mods feel it should be moved I will of course understand

I currently have a Cokin ND8 (3 stops I believe), adapter holder and 67mm ring that attaches to my Tamron 17-50... As such I'm unable to to (easily) use the ND on my 49mm thread lenses (this is about to become more annoying as I plan on buying the DA 35 Ltd towards the end of month)...

I'd really like to be able to slow things down more without sacrificing DOF, so I'm thinking a 10 top ND would be nice...

Question is: Should I buy a 49mm adaptor ring and a couple more Cokin ND8's OR buy a 49mm thread 10 stop (black glass) ND filter for use on my primes?

If its the latter... Anyone recommend a good one?

If this is to show movement such as flowing water, have you tried multiple-exposure? (Does the K-x have it?)
I did this a while back because I only had six stops but needed 10+ for the effect I wanted.
It probably isn't exactly the same but it blends real well to give a smooth silky look. It certainly looked similar enough to what the person next to me got with 10-12 stops of ND)
I don't know about the K-x, but the K5 finally makes multi-exposure usable. The K7 and prior processed each image before allowing the next photo to be taken. The K5 allows you to take all photos, then merges them after the fact... allowing greater usability.

Anyway, I'd always suggest going with something that will fit your largest lens and get step-down rings or adapters. Always cheaper than multiple filters.
Multiple NDs give more flexibility in the range of light you want to cut out, but also give the ever increasing potential for poor quality images.

Another options is the Singh-Ray Vari-ND filters. I think they go above 8 stops now.
But you pay for the convenience!

The Kx does have exposure bracketing

Not asking about exposure bracketing but actual in-camera multiple-exposure. (where the camera stacks and blends a series of images on top of each other.)
I did't recall if all Pentax cameras include that feature or not.
FYI, I've looked up on Google and it seems the K-x should be able to do this.

Again, I have not don'e any one-to-one pixel-peeping comparisons, but it might be a decent alternative and save a lot of money for a very similar effect.

I've rarely found a use for it in the past due to the excruciatingly slow processing, but the latest implementation is actually useful for creative effects. Just be sure you have the exposure control checked ON, otherwise almost all will result in being over-exposed.

K-x does... I've played with 'multi-exposure' a couple of times street-shooting... Intresting having a subject move through the frame...

I really want that dramatic moving-cloud effect so want to be able to stack NDs on top of a CPL... Just figured the slower I can get the shutter the better...

I'll try multi-exposure again with a CPL next time I'm somewhere nice on a windy day...

Cheers

i have cokin and hi tec filters and if you fit more than 2 you get a nice magenta colour cast,if you use the 10 stop hi tec you get a wonderful dark magenta photograph,on a k7. i think if you want 10 stop your better off spending more money and going for Lee or b&w, which i will have to do

I use multiple exposures in my K20D so it's been around a while. It's very useful for a number of situations -- getting longer exposures is one of those.

cool. nice to hear i'm not the only one.
note, be sure to get the latest Adobe Camera Raw an Lightroom updates. Although I guess they're a bit old by now.
I pointed out a bug to Adobe a few months ago with multiple exposure that gives a severe magenta color cast when using RAW.

just be careful there....10 stop ND might not be enough for moving clouds....unless there is really strong wind......i used it with polarizer and stoped down to f16 or f22....and still it allowed me only 4 or 6 seconds of exposure....not enough to emphasize clouds movement

10 stops is usually enough. Just remember the 30 rule, 1/30s exposure equates to a 30s with ND110 exposure. Often ND110s are a little off though, ie mine is actually closer to 11.

Multi exposure is all well and good but pants for greasy clouds really. Because you see stuttering, so instead of smooth clouds you see stops and starts.

Good advice above about buying for your largest thread. You can always use stepups to accomodate smaller ones. I have a b&w 77mm with stepups and that does me nicely for every lens I have that would use ND110.

If you're going to stack don't even bother trying the cheap Cokin range for colour photos. The colour cast is diabolical. Fine for B&W obviously