Filter Neutral Density

Filter Neutral Density
Photographers I want to use a ND filter but I don’t know which holder to buy. Help!?

I want to buy this filter

8X Neutral Density Filter
http://www.bhphotovideo.com/c/product/146972-REG/Hoya_523334_52_mm_Neutral_Density.html#features

to use with a 50mm f1.8 which holder do I buy please help

focal length has nothing to do with your filter size.
it depends on your lens, ask your manufacturer or Google it.

Photography using a Split Neutral Density Filter