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| Pond Brook Falls 67seconds, 6 Stop ND |
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| 10 Stop ND |
It is a common saying that,
“To a man with a hammer everything looks like a nail”. Over the last few days, everything has looked
like an opportunity to use my new Neutral Density Filters and I have been
having a great time.
Over the years I have used
various filters when I wanted to reduce the light reaching my camera’s
sensor. Most often this has been when I was
trying to slow my exposure of flowing water to get that soft, cotton candy
look, which I love. I routinely use my
polarizer which, with the right direction of light can knock of one or two
stops as well as cutting the reflections on the rocks. With low light, a
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| Chesterfiled Gorge Cascade, 79 Seconds |
polarizer may be all I need
to get the exposure down to 0.5 to one second, which creates a nice soft look
without obscuring all the detail in the water.
If I need to block more light, my next step has been to use my gradient
neutral density filters. I have a nice
set of Cokin filters, which are designed to block the light in a portion of the
scene. Most commonly this is helpful to reduce
the contrast between a bright sky and a foreground which is shadow, but the
portion of the filter which has the maximum darkening effect is usually large
enough to cover the entire lens. It is
an awkward arrangement but, in a pinch, it can work like a fixed neutral
density filter.
These have been my light
reduction work-arounds, they can work but are difficult and, despite my best
efforts, at most I can reduce the light by 3-5 stops, not the 6 – 10 stops that
can really change a scene. Obviously, I
needed a set of fixed ND filters that would be easy to use and provide a wide
range of light reduction options. Oh,
and they need to be high quality and low price.
Easy.
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| Ashuelot Falls 46 Seconds, 6 stop ND |
Finding a Reason to Stop at 2Filter.com
That brings us to earlier this
week. Susan and I were heading home from
a tour of possible wedding party venues for my daughter (YEH), and happened to
be passing the unobtrusive offices of 2Filter.com in Gilsum New Hampshire. 2Filter.com is a great on-Line source for
photographic filters, but it is not a retail store. The first time I made an order, I scared the
hell out of the people in the office when, upon being asked for my shipping
address, I announced that I would be dropping by to pick it up. Since then I have enjoyed a friendly
relationship with the owner and his helpful staff. On this day, I had to come up with a reason
to stop at the office and ND filters came immediately to mind. With the help of the staff, I came away with a set of Fixed NDs [3,6 and
10 stops), and also a Clear-Night Filter for my astrophotography.
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| Ashuelot River Park, 45 Second 10 Stop ND |
When buying filters, you want
to get multicoated glass filters with thin but sturdy rings. The thin rings are important to avoid vignetting
especially if the filters are stacked. My
kit of Haida fixed ND filters met my criterion and for a fair price. It was then time to go out and play.
So what situations call for
the significant reduction of light making it to your sensor?
1) Flowing
Water
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Pond Brook Cascade
1/60th second Polarizer |
The use of long exposures to make flowing
water appear like a gossamer veil is one of the most commonly used pieces of
photographic magic. Water never actually
looks like cotton candy, but it is just one way to capture the feel of
waterfalls and streams. Different slow
shutter speeds create different renderings, but on bright days, even with a
polarizing filter, it can be difficult to slow the shutter sufficiently. Neutral density filters allow long exposure
even in the brightest sunlight.
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| 60 Seconds, 6 stop ND |
For waterfalls, I typically use shutter speeds from
0.5 to one second, but I have been having fun experimenting with my new NDs for
much longer exposures. My camera only goes to exposures of 30 seconds, but with
the bulb setting I have captured my flowing water up to a minute or more. Definitely a different look and feel.
2) Moving
Clouds
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| Chesterfield Town Hall |
Technically just another kind of flowing
water, using ND filters to capture moving clouds can lead to interesting
effects. The optimal shutter speed
depends on the density of the clouds, how fast they are moving across the sky
and, of course, personal preference. I
am excited about getting the chance to experiment with angry, fast moving
clouds, but, as of this writing the weather has been too damn nice. Over this weekend I caught puffy clouds
flying by ther Chesterfield Town Hall.
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| 71 Seconds, 10 Stop ND |
3) Video
Shutter Control
It is generally understood that video has a more
natural, “cinematic” appearance with a shutter speed of 1/50th – 1/60th of a
second, which is roughly twice the usual frame rate. This can be difficult to achieve when filming
on bright days, and neutral density filters are routinely used to block the
light sufficiently to allow the optimal shutter.
4)
Bright Light Shallow Depth of Field, Especially Portraiture
Portraits are always difficult on sunny days. The stark shadows, the squinting and the flat
colors often present insurmountable challenges.
Reflectors and fill flash can help, but the bright light may also make
it impossible to open the aperture sufficiently to get a nice soft focused
Bokeh behind your subject. Many of the
newer DSLRs have faster shutter speeds that may be used to avoid this problem,
but cutting the light with an ND can also permits a wider aperture.
5) Long
Exposure Crowd Control
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| Portland Alley |
Over the years I have occasionally
been able to use long exposures to remove unwanted people or vehicles from a
scene. With a long shutter moving
subjects may not be in one spot long enough to register on the sensor.
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| 30 Second Exposure |
A few years ago, I used this technique on a
night shot of a busy alley in Portland Maine. A 30 second exposure was
long enough to remove all but the idle smokers from the scene. For the dark alley, all needed was f/22 and
an ISO of 100 to allow the 30 second exposure, but for shots in brighter light
a neutral density filter would be needed.
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| Maine Street Keene, NH |
Earlier
this week I set up on Keene’s busy Maine street in bright midday sunshine. Traffic was heavy, but I magically removed
most of the cars a 10 stop ND, f/22 and an 8 minute exposure. I couldn’t remove all the evidence of bright
car lights. This technique will work
better when used to remove people (who don’t have headlights) strolling by, and
when the motion is perpendicular to the cameras view.
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| 8 Minutes, 10 Stop ND |
Neutral Density Lessons
These are just a few uses for
fixed Neutral Density Filters. I am sure
more can be suggested. I have only been
playing with my NDs for a couple of weeks and can hardly be considered an
expert in their use, but I have learned a few things from my experiences so
far.
Stacking
First NDs can be stacked
either with themselves or with other filters.
When NDs are stacked there is a wide range of effects than can be
achieved. A 3 stop and a 10 stop can be stacked to reduce exposure by 13
stops. Although it would be unlikely to
be necessary, stacking all three filters from my new kit, I could reduce the
light by 19 stops! With that I could hit
the shutter and come back in several days to review the results.
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| Stickney Falls, Dummerston Vt, 93 Seconds |
For my waterfall pictures I
like to use a polarizer to reduce the reflections off the rocks and a polarizer
can be stacked with an ND. The polarizer
reduces the exposure by an additional stop or two. With more powerful NDs which essentially
eliminate the light, I must adjust the
polarizer as well as the composition and focus before I add the ND. Care needs to be taken to avoid moving the
Polarizer ring as the ND filter is screwed in place.
The other important issue
with stacking any filters is to watch for vignetting. This is more of a problem when thick filter
rings are stacked and when using wider angle lenses.
Focusing and Composing
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| 63 seconds, Chesterfield Gorge |
Even with relatively weak ND
filters, it can be difficult to compose and focus in the viewfinder. One approach is to focus before the filter is
added, but I found that even with moderate amounts of light reduction, I could
use Live View to focus and to adjust the effects of a polarizer on the
LCD. With the 10 stop filter, everything
was completely black and I had to make my adjustments before adding the
filter. Of course, cameras vary, and
experimentation will usually be necessary.
Exposure
Maintaining the same exposure
after adding a ND filter is simply a mater of compensating for the number of
stops. Since aperture adjustments are
limited, I tend to keep the f-stop fixed and compensate with changes in the
shutter speed, but it can get confusing when trying to count out ten stops on
the shutter adjustment.
Happily, there are several
easy Apps, available in the iTunes App Store, that make this adjustment
easy. I settled on free one (typical)
called the “Long Exposure Calculator”. You start by finding the correct exposure
without the ND. For my waterfall
pictures, this means the correct exposure with the polarizer in place. This “Base Shutter Speed” is entered into the
App and, when the filter density is dialed in, the correct filtered shutter
speed appears on the bottom. Simple, and
if the shutter is greater than 30 seconds, a timer pops up to count down the
appropriate amount of time. This works great, but if the light changes some
adjustment may be required.
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| Long Exposure Calculator |
I’ve been having great fun
with my NDs. One of the remarkable
things about photography is how even relatively inexpensive pieces of kit can
open exciting new ways of seeing our world.
Go have some fun.
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| Evening Stickney Brook Falls, Dummerston Vt : 60 sec 6 Stop ND |
I know that
it is Tuesday and I am WAY late for my usual Sunday Blog posting, but you are
lucky, or maybe not, to get anything at all!
