Need ND Filter Help!

[John B.]

Originally Posted by clickin girl

Hello guys! I have fallen in love with daytime long-exposure and want to try my hand at it. I want to buy a ND filter but not sure which one to get. I have done some looking around online and some photogs use 2 stop, some use 3 stop, and some use 10 stop. I am limited on budget and can only buy one right now. I am leaning toward the 10 stop, but if you could only buy one what stop would it be?

Just a suggestion if you haven't already done it, make sure your ISO is manually set to 100 and not automatic. Also use the camera in aperture priority mode, and the smallest aperture (usually around f/22 depending on the lens). Those things will make the camera as slow as naturally possible. Then you won't need an expensive 10-stop filter.

[jet_kit]

Originally Posted by John B.

Just a suggestion if you haven't already done it, make sure your ISO is manually set to 100 and not automatic. Also use the camera in aperture priority mode, and the smallest aperture (usually around f/22 depending on the lens). Those things will make the camera as slow as naturally possible. Then you won't need an expensive 10-stop filter.

As the old song goes, "It Ain't Necessarily So."
Nice bright sunshine at ISO 100 will give you about 1/60 at f22. This is nothing like slow enough for the effect Clikin' Girl is looking for. By contrast ISO 100 at f11 and a 10-stop ND will give about 8 seconds which is more like it. Even this may not be slow enough for the cloud effects she's after; Stopping down to f22 will only give her 16 seconds, whilst she could need minutes depending on how fast the clouds are moving. Bearing in mind that she's shooting the sky (which is a lot brighter than Auntie Mabel under the Apple Tree), the necessary combination might have to be TWO 10-Stoppers!

[GeoffWessex]

Also worth noting that using "the smallest aperture" can also be a problem. All lenses work best at an 'optimum' aperture - usually around f/8 - and using the narrowest apertures can produce lens diffraction and reduce the quality of the image (which already has its work cut out with a dark filter in front of it). Open up by a stop (at least) for better quality - say f/16 or even f/11. Yes, it will then make your exposures shorter, defeating the object to some extent..... but it's best to leave it to the filter to force the slow shutter.

Then, of course, a long exposure can also reduce the quality by introducing noise (becoming less of a problem with newer cameras) and the fact that a long exposure needs a very rigid camera - the longer it takes, the more chance of camera movement.

[donoreo]

Originally Posted by GeoffWessex

Also worth noting that using "the smallest aperture" can also be a problem. All lenses work best at an 'optimum' aperture - usually around f/8 - and using the narrowest apertures can produce lens diffraction and reduce the quality of the image (which already has its work cut out with a dark filter in front of it). Open up by a stop (at least) for better quality - say f/16 or even f/11. Yes, it will then make your exposures shorter, defeating the object to some extent..... but it's best to leave it to the filter to force the slow shutter.

Then, of course, a long exposure can also reduce the quality by introducing noise (becoming less of a problem with newer cameras) and the fact that a long exposure needs a very rigid camera - the longer it takes, the more chance of camera movement.

Aren't you mister negativity

[GeoffWessex]

Nooo - Negatives are a thing of the past!

The loss in quality in using the smallest aperture is, to be fair, almost negligible - unless the image is printed quite big. But it's there, eh?

And you need a sturdy camera support to be completely sure there's no camera movement - so a lightweight tripod could be a problem if it's windy.

Photography, from the aperture/shutter-speed calculation onwards, is all about 'what you gain on the swings you lose on the roundabouts'.

[John B.]

Originally Posted by jet_kit

As the old song goes, "It Ain't Necessarily So."
Nice bright sunshine at ISO 100 will give you about 1/60 at f22. This is nothing like slow enough for the effect Clikin' Girl is looking for.

I never intended my comment to mean it would satisfy the effect she is trying to achieve. And I never meant she would not need a filter.
I was only saying she won't need an expensive 10-stop filter. A lesser one will do. My suggestion was only meant as a starting point. Auto ISO will work against her, and so will a maximum aperture.

[jet_kit]

Originally Posted by John B.

I never intended my comment to mean it would satisfy the effect she is trying to achieve. And I never meant she would not need a filter.
I was only saying she won't need an expensive 10-stop filter. A lesser one will do. My suggestion was only meant as a starting point. Auto ISO will work against her, and so will a maximum aperture.

Sorry John, but your response was a bit definitive. I think you need to read my reply a bit more carefully - Clickin' Girl will need the 10-stop and possibly more to get what she wants.

[donoreo]

Originally Posted by GeoffWessex

Nooo - Negatives are a thing of the past!

The loss in quality in using the smallest aperture is, to be fair, almost negligible - unless the image is printed quite big. But it's there, eh?

And you need a sturdy camera support to be completely sure there's no camera movement - so a lightweight tripod could be a problem if it's windy.

Photography, from the aperture/shutter-speed calculation onwards, is all about 'what you gain on the swings you lose on the roundabouts'.

Yes, everything you said is true, I was just being somewhat silly.

[GeoffWessex]

Good comments from everybody here....... there are lots of pros and cons to filters, long lenses, shutter speeds, apertures etc and it's worth airing them.......... hey, if all cameras really were 'point and click' or had 'modes' for every conceivable technique, most of us wouldn't bother with photography at all, would we?