Neutral Density (Newbie ?)

[Darkninja462]

For Neutral Density Filters what does it mean by :

Authorizes a 1 stop Shutter speed/Aperture decrease.

Does that mean to get the same picture without the filter if you alter those settings ?

Sorry for the newbie question would just like it cleared up
Looking ideal to use it with water if that helps.


Ninja

[RichardTaylor]

That's correct. However without a ND filter you may nit be able to reduce your shutter speed to the value you want (it depends on the available light and the minimum aperture of your camera).

[Big Nick]

Originally Posted by Darkninja462

For Neutral Density Filters what does it mean by :



Does that mean to get the same picture without the filter if you alter those settings ?

Sorry for the newbie question would just like it cleared up
Looking ideal to use it with water if that helps.


Ninja

No, if you just increased your settings on your camera with out using a Neutral Density Filter you would over expose your image. More or less when you put a ND filter on you are putting sunglasses on your lenses. This allows you to change these speeds and still allow you to take a photo at the proper exposure.

I hope this helps

[Darkninja462]

I think I confused myself, let me re-frase it

When I put my ND filter on what do I need to change ? or what would you suggest to change ?

Ninja

[Big Nick]

Originally Posted by Darkninja462

I think I confused myself, let me re-frase it

When I put my ND filter on what do I need to change ? or what would you suggest to change ?

Ninja

It really depends on what you are shooting. I usually use ND filters to change my shutter speed. This way I can take longer exposures which are great for say moving water or getting motion blur in sunny situations.

[Darkninja462]

That's what I'm aiming for water effect I suppose its just a case of trial and error with that in mind I think ill shall wander down to the local park and take some pictures of the waterfalls/weirs or if its raining use the tap at home

[dakwegmo]

A ND filter reduces the amount of light reaching the sensor. If you have a one stop ND filter on your lens then the amount of light is reduced one stop. If proper exposure without a ND filter is 1/250, f/16, ISO 200. Then you'll need to do one of three things to increase compensate for the loss of light reaching the sensor: slow your shutter speed to 1/125s, open up your aperture to f/11, or increase ISO to 400. Depending on what effect you're going for one of these may be a better choice than another. Most of the time when I use a ND filter it's to get slow shutter speeds for long exposures, so I usually choose a slower shutter speed.

[Darkninja462]

Thank you that's the information I wanted to hear I shall try that out.

Many Thanks

Ninja

[inkista]

The other reason to use an ND filter is to use a wider aperture and get a smaller depth of field at a slower shutter speed. Say, if you're limited by the x-sync speed on your flash to using 1/250s, but you want to shoot with your 50mm f/1.4 wide open at f/1.4. In the daytime, this could well put you over 1/250s, even if you shoot at iso 100.

The stops of the ND filter are important, because you need to know what your target shutter speed is. To get the flowing water effect, you usually need a shutter speed of a few seconds. So, if in normal circumstances, a good exposure would cause you to be at 1/60s, and you wanted a 1s exposure, you need to know how many stops that is.

A stop is a doubling/halving of the amount of light. So with iso and shutter speed that means a doubling/halving of the setting. With aperture, that means a full stop on the f-number scale.

So, in the example of trying to move your shutter speed from 1/60 to 1s, you'd need

1/60 -> 1/30 -> 1/15 -> 1/8 -> 1/4 -> 1/2 -> 1s . Which is 6 stops. I do know that my personal tendency is to underestimate how many stops I'll need, because I live someplace that's horribly sunny. For me, a single-stop ND filter is no damn use. But then, I tend to buy very dark sunglasses.