[daacon]

I just purchased some Hoya ND filters for some long exposure water shots. My question is how ?

I will have the opportunity to shoot some fountains in a few days , probably in harsh daylight and at night just wondering how this whole process works. I assume I have the ND filter on and then set a shuuter speed in TV mode ? Is it more or less hit and miss approach ? Is there a more scientific approach ?

Edit: Oh and I have 2 4 and 8 how do I determine which one to use ? I am hoping there is a tried and true method ... then again it's digitial and the hit and miss method only costs time.

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Last edited by daacon; 07-15-2009 at 07:41 AM.

[Ben_Edict]

I just purchased some Hoya ND filters for some long exposure water shots. My question is how ?

I will have the opportunity to shoot some fountains in a few days , probably in harsh daylight and at night just wondering how this whole process works. I assume I have the ND filter on and then set a shuuter speed in TV mode ? Is it more or less hit and miss approach ? Is there a more scientific approach ?

Edit: Oh and I have 2 4 and 8 how do I determine which one to use ? I am hoping there is a tried and true method ... then again it's digitial and the hit and miss method only costs time.

If anything, you won't use Tv, as you don't want the camera to pump up the ISO, to get a short exposure time... Use a fixed low ISO setting (aka 100), close down the aperture to f/16 or f/22 (whatever your lens allows) and then the camera will choose (in Av mode) the matching long exposure time.

In broad daylight you will probably use the ND8 filter to get an exposure time of 1s or 2s - But perhaps a shorter exposure time of 1/10s will give a more natural look - though it is sure best to try different expsoure times with the different filters in order to get a feel of the different appaerance of the water over integration time.

Ben

[Ratmagiclady]

I just purchased some Hoya ND filters for some long exposure water shots. My question is how ?

I will have the opportunity to shoot some fountains in a few days , probably in harsh daylight and at night just wondering how this whole process works. I assume I have the ND filter on and then set a shuuter speed in TV mode ? Is it more or less hit and miss approach ? Is there a more scientific approach ?

You should still be able to meter normally, or use Tv, if that's what you mean. That, or you can meter with no filter on, and correct for the factor of the ND filter you'll be using. They're designed to be known quantities. (Edit: Oh, yeah, in light of Ben's post, don't set ISO to auto if you want to use TV: I always select that manually, unless maybe I'm using TAv mode. )

As for what shutter speed to choose, it'd probably be good to experiment somewhat: you can get very different effects with different shutter speeds, with different waterfalls, and other factors.

[Nesster]

If you're metering TTL, with the ND filter on you don't have to make any other adjustment, the meter is already reading through the filter!

To get longer exposure, yes you can go Tv and let the camera set aperture - but the way I'd do it is as Ben recommends - set aperture to a value that gets you a long enough shutter speed. Personal preference, either way, or even manual exposure setting, will work.

For daylight shots, you may want to stack a polarizer or a second ND filter in order to get a long enough shutter speed.

[daacon]

Awesome - thanks for the tips All makes sense.

[Venturi]

The ND filter numbers (2, 4, 8...) are the powers of 2 of the full stops of light reduce by the filter. An ND2 is 1 stop, ND4 is 2 stops, ND8 is 3 stops. I'm sure there's a really good reason for complicating the numbering related to zone system calculations or something - dunno, but that's what they mean anyway. If you knew that already, my apologies but your inquiry read like you were trying to make sense of what each filter did.

IMO, since you're shooting flowing water shutter speed is your main priority, so use M or Tv mode. Set your ISO (or pick your film) and shutter speed as your creative vision dictates, and apply your ND filter(s) to get the aperture into the range you want. That's my method anyhow, for what it's worth.