Here are 3 filters from 3rd party Chinese, what made me to post them are the price and the material used to make the filters, GLASS, i always prefer glass even not high quality over a resin high quality, i bought 3 filters from 3rd party glass which were last pieces [lucky me] and all giving me great results when used with any lens.
A. 2/3/10 stops ND:
http://www.ebay.com …Shott-Glass-/121497085981
http://www.ebay.com …Shott-Glass-/111527600456
http://www.ebay.com …9de653:g:cQkAAOSwPcVVmlFC
3 of them together will cost about $160 if no shipping, this price is nearly as one BIG stopper filter from LEE. You can Choose Haida which is little bit more but still cheaper than LEE/Singhray/Hitech glass versions, so i no longer look at those high brands anymore.
B. 2/3 stops GND:
http://www.ebay.com …t%3D6%26sd%3D151810525268
http://www.ebay.com …t%3D6%26sd%3D151810525268
I think you don't both, one of them is enough, i recommend going with 0.9 [3 stops] over 0.6, and Haida is a good filter brand and the quality isn't bad, glass too, if you find something else go for it, but i keep recommending glass filter over any plastic/resin ones regardless which brand you buy, i have LEE and Hitech resin filters and i want to buy them all, not because of low quality as they are all high quality with LEE is winner, but the resin material isn't good for scratches and flares and also color cast very slight, and cleaning is a pain in .... so even if the glass has some cons i accepted over how many cons with resin.
And here is a square CPL that you can give it a try:
http://www.ebay.com …044813:g:LMQAAOSwPgxVRzZW
Couldn't find something cheaper, i bought the LEE one before knowing about Haida, CPL glass square filters are expensive anyway from all brands even 3rd party, i saw another one cheap but i can't tell about the quality, it sounds it is deigned more for video cameras than still, but it may be used find for DSLRs, you can buy it and give it a try with that price, if it is great then others may like to buy it as a cheap alternative too.
http://www.ebay.com …a5b58b:g:9pQAAOSwcF9UWENi
About filter holder and adapter rings, also from ebay i can choose any filter holder that is designed for 4"[100mm] filters and i will go with the metal design one [Aluminium maybe] over plastic one, it is not a very big factor as i bought LEE and Hitech and both are doing the job just fine, also try to have a wide angle adapter rings, 77 and 82 are the most used for me
With above kit even if you pay a lot i assure you won't look anything else, it will be used for different many lenses for long time, i regretted buying resin filters and i am trying to sell what i have already even hitech ones, i don't stop buying $300-500 filters kit as i don't want to put something cheap in front of my expensive lenses, and with glass i won't worry much about color cast, and those 100mm filters will reduce the vignetting so much, i don't mind slightly vignetting, but i know if i didn't use those kit i will see ugly/too much vignetting at widest FL [10-18mm on FF], i took a long path/way until i found my ultimate filters kit, also you can ad something like reverse ND and Vari ND just for more effects if needed, but the above are standard to start with and use more, and some will say they don't use filters anymore because they are masters with software to have same effects, to me it is always less headache to have almost good enough shots from camera before i touch it with software for even further better results.
Good luck!
