I'm in a bit of the same situation myself. Either the X-Pro or the P series holders should work. Cokin is ok, but from what I've read Lee is better and Singh-Ray is the best. Many people say Cokin ND filters tend to have a little color cast. But a lot of people use them just fine, so it probably depends on if you are willing to deal with the color cast or not..

Also, since all of these type filters are an optical resin rather than glass (except for a few exceptions) they are easily scratched and can warp if left in high heat very long. Just be aware of that and treat them accordingly..

My plan is to try and snag a couple of the Cokin filters on eBay just to get a feel for it, then maybe save my pennies (ok...it'll take dollars) and get some Sing-Ray filters eventually.Chefziggyhttp://www.pbase.com/chefziggy/lecream.

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One thing that Cokin does have in it's favor is longevity. I have had mine for many years. The quality is very ok to quite good, but it is not the best of the best. It all depends on how picky you are. At least you know though that you won't get stuck with stuff that will be discontinued in 5 years. I used to use their diffusers a lot doe that dreamy wedding stuff people seem to like..

If going to shoot fine art landscapes I would definitely go Singh-Ray, but they may a LOT more than what is in your budget. The prices are on their website..

Here is a Singh Ray ND review, and there is a link to the Singh Ray site at the bottom of the page..

Http://www.f-8andbethere.com/tips/filters.htm.

Have had some of my Cokins for 10+ years and no detioration with good care. Sorry I don't have any experience with Lee.Age and treachery will always overcome youth and skill..

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See my throwaways on Flickrhttp://www.flickr.com/photos/niagaragirl/..

Thankyou for the advice! believe it or not I had not heard of singh-ray before you mentioned it, I'm glad I checked it out now, I may save up for some of them instead (dollars is right, so expensive here in UK)..

Im so confused about the size. I thought only x-pro could be used below 20mm focal length, and thought that p-series was a different smaller size, is it actually possible to use p on my sigma 10-20? am I right in thinking that the xpro and pseries are two different systems with no cross-compatable bits? If I buy singh-ray, what filter holder would I need-still cokin? and which sing-ray size fits which holder...? do you find bellows or some device to cover the back of the glass/resin from light are necessary?.

Sorry for all these questions, ive been looking through online brochures for weeks and I feel I know less than when I began looking! it also seems that no-one has them in store to look at or knows anything about them..

Thanks again for your help..

I can't help in terms of sizing, but I just bought the Cokin P system for my 18-70..

I bought two of their ND Grads (121 and 121L, I think), and they had a pronounced magenta cast to them, which took quite a lot of playing with to remove in Photoshop..

I looked around and most people recommended HiTech, as well as Lee and Singh Ray. Turns out they're made in Wales and are available for remarkably reasonable money. I've only had limited experience with them so far and they seem very good. I've certainly not had to correct for colour casts since using them..

Http://www.formatt.co.uk/stills-filters/products.aspx..

Have you checked out 2filter.com? I am in a rush so just some quick thoughts....

Lee makes it's own holders. Some other companies make filters for use with cokin holders..

Here is an example:.

Http://www.2filter.com/prices/4x4filtergradkit.html.

2 filter is a US based company but it's a good site to look over for the range of possibities out there....

Good luck!.

Nancyhttp://diggin99.smugmug.com/..

Cool, thanks for that, ill check out the site:).

Marwood, do you find you get light fall off/vignetting at 18mm with the p-series?.

Cheers!..