[BIG HEAD MAN]

ND 鏡有多種號碼,2x 4x 8x,請問有何分別,只買一款有何見議?

[neu]

the bigger "x" the darker the filter would be, and then reduce more light. think sunglasses and you would understand.

there are different ways to label nd filters. eg. hoya use "nd x4" to describe the same filter "0.6" in kodak.

i found 0.6 and 0.3 wratten nd gel filter useful. for 0.6, it reduces 1 ev of light and takes 2 stops for compensations. 0.3 reduces 0.5 ev & needs +1 f/stop. kodak has a wide range of gel filter available, from 0.1 to 4.0. the "darkest" one i had was a 3.0 nd that took +10/f stops compensation!!! but in that kind of situation, it is far too extreme/bright to shoot. 0.3 and 0.6 should cover most situations.

there are different types of nd filter. would u consider wratten gelatin filter (魚膠中性密度濾光片) or glass type (玻璃濾光片)? technical speaking, gelatin is the best but more troublesome as u need to get the whole set of filter holder.... they are less durable, expensive and difficult to purchase. BUT if your lense has internal filter holder, like canon ef 17-35 2.8L, then you might want to get a regular size (75mm) gel filter of 0.3 to make 2 pieces of small size nd filter. insert 1 piece for 0.3 (o.5 ev) and 2 pieces for 0.6 (1ev). that could save some $ la. buying one filter and make 2 smaller pieces to cover 0.3-0.6.

if you want to use glass nd filter, then i'd recommend hoya. x4 should be the same as 0.6 if i remember correctly.

for precise techncal data, pls check kodak L9 catalog and it's website. my experience of using filters is quite outdated. pls correct me if i am wrong.

hope the info'd help. happy shooting

[BIG HEAD MAN]

多謝 neu 的詳細講解, thanks!!!!!!