what can a ND filter do?

[ryan84]

what the different between x2,x4,x8?

 

[latmo]

what the different between x2,x4,x8?

http://www.thkphoto.com/products/hoya/oef-05.html

 

[Adiemus]

The more "x"s, the more stops of light it cuts off.
so effectively, a 2x cuts of less light than a 8x ND filter.

 

[ryan84]

let say i shooting waterfall and mountain..
which X? is better?
or is it depend on the lighting of the day...

 

[foxtwo]

it depends more on how long u want open ur shutter to get ur intended effect.

 

[ryan84]

so the theroy is say that when i set at 15sec and i use x2 ND filiter and i get 30sec of shutter because it x2?

 

[latmo]

no ..... :nono:
read the website i post ...

 

[tingchiyen]

so the theroy is say that when i set at 15sec and i use x2 ND filiter and i get 30sec of shutter because it x2?

If you set your filter at 15 secs, you'll get 15 secs. The x2 ND filter will reduce the light entering by 1 f/stop, which means, if without filter you get an equation of 15 sec : f/11, with the filter you should use 15 sec : f/8. Which also means you can push the f/stop higher and get longer exposures. The filter's to prevent over-exposure outside the f/stop values available to you to play with, when you really want to get long exposures. Try using shutter priority with the filter, might be easier for you, if all you want to do is get a specific motion effect, like waterfall curtains etc. Hope that helps.

 

[latmo]

If you set your filter at 15 secs, you'll get 15 secs. The x2 ND filter will reduce the light entering by 1 f/stop, which means, if without filter you get an equation of 15 sec : f/11, with the filter you should use 15 sec : f/8. Which also means you can push the f/stop higher and get longer exposures. The filter's to prevent over-exposure outside the f/stop values available to you to play with, when you really want to get long exposures. Try using shutter priority with the filter, might be easier for you, if all you want to do is get a specific motion effect, like waterfall curtains etc. Hope that helps.

erm
think should be with filter F11 without is F8

 

[tingchiyen]

erm
think should be with filter F11 without is F8

Nope, with filter = less light = wider aperture. :think:

 

[latmo]

Nope, with filter = less light = wider aperture. :think:

F number bigger mean the hole is smaller .......

 

[foxtwo]

tingchiyen's Point:

1. correct metering at 15secs = f11
2. metering with NDx2 = f16 (-1stop)
3. compensate 1stop light loss = f8

latmo's Point:

1. correct metering at 15secs = f8
2. metering with NDx2 = f11 (-1stop)

Am i correct?

 

[tingchiyen]

haha yeah... thanks, fox.
but don't confuse ryan! just plunk on the filter and use shutter-priority! :thumbsup: