Neutral Density Filters

[Statto]

Hello All

I have been reading about the benifits of ND Filters and would like to purchase one

The problem being that the articles I have read say that you want to be looking at 10 stop ND Filters

The darkest 55mm ND Fliter I can find is an 8x (three stops)

My question to your guys is this

If I fitted two 8x filters together would I effectivly get a 9 stop filter? (3stops x 3 stops = 9 stops)

Cheers
Statto

[dcclark]

Noooo... unless you have very specific needs, you don't need a 10-stopper. I own a 3 stop (8x, sometimes also called 0.9), and it's almost always more than enough for (for example) a 1 or 2 second waterfall exposure in bright sunlight, or a 3-5 second exposure in shade.

If you fitted two filters together, they would absorb a total of 6 stops (3 stops each). However, the result would probably be some heavy-duty vignetting (shadowing around the edges).

But again, you almost certainly don't need a 10 stop filter. What kinds of articles have been advising that?

[Statto]

Originally Posted by dcclark

Noooo... unless you have very specific needs, you don't need a 10-stopper. I own a 3 stop (8x, sometimes also called 0.9), and it's almost always more than enough for (for example) a 1 or 2 second waterfall exposure in bright sunlight, or a 3-5 second exposure in shade.

If you fitted two filters together, they would absorb a total of 6 stops (3 stops each). However, the result would probably be some heavy-duty vignetting (shadowing around the edges).

But again, you almost certainly don't need a 10 stop filter. What kinds of articles have been advising that?

It was an article in this months 'practical photography' magazine in the UK, the idea behind the 10 stop is so you can get 30second exposures in bright daylight

[Statto]

Hey David

Ive just had a look at your web store

The pics of flowing water you have on there have very nice 'silky' water effects.
Do you get these results using 3 stop density filter (8x)?

Cheers
Statto

[dcclark]

Statto -- why do you need a 30 second broad daylight exposure? Unless you can answer that question, you probably don't need it. (One common use is to "remove" moving objects, since the exposure is so long. But in that case, any fixed objects which move, such as a tree, will appear very blurry.)

It's a very special kind of photography. For waterfalls, such as those on my photo site (thanks!), I used a 1/2 second or maybe 1 second exposure with my 8x filter.

[OsmosisStudios]

B&H have B+W ND filters, 55mm, 10-stop. $40.50 for the standard, $65 for the slim.

Super density filters are very specialized and often unnecessary, but they sure can be fun.

[dakwegmo]

The difference between a 1-2 second exposure and a 30 second exposure can be very dramatic, but unless you're trying to get extremely long shutter speeds (to capture the swirls in slow moving water, for example) or you also want a very shallow depth of field, the 10 stops are overkill, especially if you're also using a CP to reduce reflections. That said, if you're going for the effect, 10 stop ND polarizers are listed as 3.0 filters, and can be had here: B+W | 72mm #110 Neutral Density (ND) 3.0 Glass Filter | 65066724

Click on the features tab, and you'll see a chart showing you how each of the numbers ND .3, .6, .9 etc. translate into stops of light filtered.

[nemesis256]

Originally Posted by dcclark

Noooo... unless you have very specific needs, you don't need a 10-stopper. I own a 3 stop (8x, sometimes also called 0.9), and it's almost always more than enough for (for example) a 1 or 2 second waterfall exposure in bright sunlight, or a 3-5 second exposure in shade.

dcclark, what aperture are you shooting waterfalls at? I don't have any experience with 10 stops ND filters, but I get a feeling that it would be very useful for waterfalls that are in the direct sunlight. I'm asking about the aperture because I don't want to get smaller than f/16 due to the possibility of having diffraction in my images.

[dcclark]

Originally Posted by nemesis256

dcclark, what aperture are you shooting waterfalls at? I don't have any experience with 10 stops ND filters, but I get a feeling that it would be very useful for waterfalls that are in the direct sunlight. I'm asking about the aperture because I don't want to get smaller than f/16 due to the possibility of having diffraction in my images.

I'm typically in the f/10 to f/16 range, depending on sunlight or shade. Waterfalls still look great, even only at 1/4 to 1/2 second. Diffraction is really hard to see, unless your image quality is so amazing and your technique so perfect that nothing else affects image quality.

Some examples:

Douglass Houghton Falls: 1/4 sec, f/22, handheld in partial sunlight, no filter. The blur is from being handheld, not from diffraction.
Spring Falls: 1/2 sec, f/14, handheld in shade, filter.

[OsmosisStudios]

I have to say, I prefer a longer shutterspeed. Clark, your shots are awesome (Spring Falls, in particular), but to get that truly ghostly water, you nee several seconds.

I managed to get this one without a filter on a very overcast summer day a few years ago. Its a 15s exposure, 100ISO at f/22. I've had it blown up and, though you can see a bit of diffraction, its negligeable. That's why I love heavy-duty ND filters: it lets me open it up to f/11 and keep the same exposure, or keep it stopped down and get total ghosts.

Im looking at an ND1000 (10stop) filter for use in similar situations and during the brightest days of summer. Theyre just so expensive in 77mm guise.