Daytime Long exposure photos

[Lebanese]

HI
I am improving my shooting skills with the filters,first I bought B+w polarizer nano coating circular filter to make impressive photos at river removing the light reflection .Now I want to shoot long exposure photos using bulb and I have over exposure images so correct me if am wrong I need Nd filers ..But the question is which one should I buy ? I found one and I want to make sure it will be the right choice since I will order it online. Zomie 77mm HD 2Nd-400ND variable filter it say that its 8 stops filter
your ideas please

[TCampbell]

Commonly it's a 10-stop filter for these long exposure stops.  If the filter is listed in "density" values then each "0.3" worth of density is equal to 1 stop of exposure (0.1 is 1/3rd stop).  That means you'd be looking for an ND 3.0 filter.

One quirk... the filter is so dark that you cannot see to compose, focus, or get an exposure reading.  This means you do all that with the filter removed, focus, get a meter reading (in manual mode) then turn off the auto-focus, insert the filter, manually increase the exposure by 10 stops before taking the shot.

I have a B+W ND 3.0 thread-on filter as well as a Lee "Big Stopper" filter (slide-in type).

In "Sunny 16" conditions it would take you from f/16 at 1/100th (ISO100) down to a 2 second exposure.  (an 8-stop would only take you down to 1/2 sec.)  

[jrhoffman75]

I have no personal knowledge of the product, but an Amazon reviewer said it has a strong color cast. That is a known problem with many less expensive ND filters. Getting the "neutral" into "neutral density" seems to require a higher quality product.

You can Google reviews and make your own determination if no one on the Forum has any direct experience.

[Lebanese]

As I have mentioned before I got b+W POLARIZER nano coating can I attach to it a second circular nd3.0 filter?
I was looking for an nd filter with a budget betweeen 50 and 100$ b+w has one with single coating around 80$ while multi coating reaches 150$! Some how I am still confused which one to buy!