Help with Neutral Density filters: Hoggers, I'm having difficulty making sense of the numbers on an ND filter. In one article I read (...

Triplets Loc: Reading, MA

Hoggers,

I'm having difficulty making sense of the numbers on an ND filter.

In one article I read ( http://www.digitalcameraworld.com/2015/11/13/how-and-when-to-use-nd-filters-and-what-the-numbers-mean-2/ ), it says ND128 is a 7-stop reduction. But when I search ND filters at B & H, I see B+W ND110 that is listed as a 10-stop reduction ( http://www.bhphotovideo.com/c/product/752927-REG/B_W_1066177_77mm_110_Solid_Neutral.html ).

Can anyone shed light on this for me?

bsprague Loc: Lacey, WA, USA

There is a useful chart here: http://en.wikipedia.org/wiki/Neutral-density_filter

Triplets Loc: Reading, MA

bsprague wrote:

There is a useful chart here: http://en.wikipedia.org/wiki/Neutral-density_filter

Thanks...I guess there is no "standard" system. Chart is somewhat helpful.

Regards,

Dennis

big-guy Loc: Peterborough Ontario Canada

For every stop, the amount of light either increases or decreases by a factor of 2. When using a ND the light is reduced.

1 is the base exposure (no filter)
2 is 1 stops difference, twice or ½ the light (from base)
4 is 2 stops difference, 4 times or ¼ the light (from base)
8 is 3 stops difference, 8 times or 1/8 the light (from base)
16 is 4 stops difference, 16 times or 1/16 the light (from base)
32 is 5 stops difference, 32 times or 1/32 the light (from base)
64 is 6 stops difference, 64 times or 1/64 the light (from base)
128 is 7 stops difference, 128 times or 1/128 the light (from base)
continue as you wish...

bsprague Loc: Lacey, WA, USA

Dennis,

The answer is in the chart. It is more than "somewhat" helpful! ND filters are used in so many applications like microscopes, telescopes, movie cameras and on, there are different numbering or rating systems. The easiest for photographers is the f-stop reduction.

One rating system states that an ND128 will give a 7 stop reduction. A different rating system says an ND 110 (notice the space) is 10 stops.

The charts shows how an ND128 is equal to a ND 107.

To make it worse, the various brands will use different systems.

Triplets Loc: Reading, MA

big-guy wrote:

For every stop, the amount of light either increas... (show quote)

That part I understand. My confusion is determining the difference in the number of stops. As I stated earlier, one article stated ND128 = 7 stops while a vendor's description stated ND110 = 10 stops.

Triplets Loc: Reading, MA

bsprague wrote:

Dennis, br br The answer is in the chart. It is ... (show quote)

DGStinner Loc: New Jersey

Triplets wrote:

That part I understand. My confusion is determining the difference in the number of stops. As I stated earlier, one article stated ND128 = 7 stops while a vendor's description stated ND110 = 10 stops.

There's a space between ND and 110 which helps differentiate it from something like ND128 which don't have a space. When there's a space between ND and the number, the last two digits are the number of stops. For something like ND128, it's a matter of what power of 2 would equal 128. 2^7=128 so ND128 is a 7 stop filter.

Triplets Loc: Reading, MA

DGStinner wrote:

There's a space between ND and 110 which helps differentiate it from something like ND128 which don't have a space. When there's a space between ND and the number, the last two digits are the number of stops. For something like ND128, it's a matter of what power of 2 would equal 128. 2^7=128 so ND128 is a 7 stop filter.

Thank you...that makes sense to me.

rmalarz Loc: Tempe, Arizona

Triplets wrote:

Hoggers,

I'm having difficulty making sense of the numbers on an ND filter.

In one article I read (http://www.digitalcameraworld.com/2015/11/13/how-and-when-to-use-nd-filters-and-what-the-numbers-mean-2/), it says ND128 is a 7-stop reduction. But when I search ND filters at B & H, I see B+W ND110 that is listed as a 10-stop reduction (http://www.bhphotovideo.com/c/product/752927-REG/B_W_1066177_77mm_110_Solid_Neutral.html).

Can anyone shed light on this for me?

Having, and being knowledgeable in its use, a Capt. Midnight Secret Decoder Ring, will help immensely.
--Bob
8-)

PhotoArtsLA Loc: Boynton Beach

I suggest getting a variable ND filter equal to the largest filter size of the largest lens you intend to have. Then, with simple, cheap step down rings you have an array of neutral density for all your lenses without having to adorn each lens separately.

Triplets Loc: Reading, MA

PhotoArtsLA wrote:

I suggest getting a variable ND filter equal to the largest filter size of the largest lens you intend to have. Then, with simple, cheap step down rings you have an array of neutral density for all your lenses without having to adorn each lens separately.

That has been suggested to me in the past and I find it to be good advice.

big-guy Loc: Peterborough Ontario Canada

It is called a step-UP ring which, as an example, allows you to use a large 72mm filter on a small 49mm lens. (step up to the filter)

A step down ring (very little use these days) allows you to use, following the above example, a small 49mm filter on a large 72mm lens and yes that will involve vignetting. (step down to the filter)

PhotoArtsLA wrote:

I suggest getting a variable ND filter equal to the largest filter size of the largest lens you intend to have. Then, with simple, cheap step down rings you have an array of neutral density for all your lenses without having to adorn each lens separately.

rmalarz Loc: Tempe, Arizona

PhotoArtsLA wrote:

I suggest getting a variable ND filter equal to the largest filter size of the largest lens you intend to have. Then, with simple, cheap step down rings you have an array of neutral density for all your lenses without having to adorn each lens separately.

Variable ND filters can cause a myriad of issues, mostly a cross pattern in the image. They apparently work at particular f-stops, but not all f-stops.

Prior to purchasing one, I called Schneider and spoke with one of their personnel. They were very forth coming in stating the issue exists in all, including theirs. I decided to purchase the fixed ND filters instead.
--Bob

bsprague Loc: Lacey, WA, USA

I think most only need two simple ND filters.

My kit contains a 3 stop for shooting in the brightest of sunlight when I want to open the aperture a little or slow the shutter speed a little, especially for video. I also have a 10 stop for "creative" water flowing and motion scenes. I don't think the variable versions are worth the price or that good at the higher settings.

For the graduated density versions, they split the image at the middle and make composition a PITA. It is better and easier to get the dynamic range of a RAW capture and make the adjustments in software like Lightroom.