expose to the right rule in mind, how about those deep, dark canyons
and rain fed rivers. Sometimes they have the most epic scenery but can
be hard to photograph well. Let's tackle the second most common issue
in whitewater photography, motion blurred photographs.
is not enough light to shoot our ideal settings, it's time to play a
game of balance with our three previously mentioned controls, Shutter
Speed, Aperture and ISO.
First we can
adjust our shutter speed, because the slower the shutter the more light
we let in. The problem with this is that rarely do you want motion blur
in a kayaking shot. I consider my slowest acceptable shutter speed to
be 1/500 to 1/800 depending on the situation. You will have to judge
this based on the speed of the paddler and water. If you are freezing
motion at the top of a waterfall, both the paddler and water will be
going slow enough that 1/500 might work (although paddle blades can
Here the paddler is nice and
crisp both the paddle blade and splashes make it feel soft overall. Nikon D200. Nikkor 18-200 @
70mm. Shutter: 1/500 Aperture: F5 ISO: 500
On the other hand,
if you are trying to freeze action at the bottom of a waterfall,, it's
will be moving much faster and harder to freeze, and thus will blur.
Shutter speed is the weakest of the three methods for adjusting
exposure on dark days, because you only gain one stop of light going
from 1/1000 to 1/500.
ISO, the equivalent of
film speed, will play a role on dark days but has some serious
drawbacks. Noise, the digital equivalent to film grain (often looking
worse) is the most well known drawback. Outside of noise, using a high
ISO also drops your dynamic range and the sensors ability to correctly
capture color and texture. But there are occasions where there is no
other option than to pump the ISO up. This is where they amount of
money you spend on a camera can make a big difference. Whatever you do,
do not, I repeat, do not, under-expose a high ISO shot. If you are
shooting at your camera's base ISO you have quite a bit of flexibility
to adjust the exposure while post-processing. (Which will be it's own
tutorial) At high ISO's any noise is greatly magnified if you adjust
the exposure, and this can ruin a great shot, making it even worse than
too slow of a shutter speed.
Example One: Shutter:
1/1000. Aperture: F4.8. ISO: 800. Post production +2.5 exposure.
Example Two: Shutter: 1/640.
Aperture: F2.8. ISO: 800 Post production +.25 exposure.
While the difference is pretty
obvious, it's even more obvious when the images are cropped at 100%:
ISO: 800, Post production +2.5
ISO: 800, Post production
Although a little bit
of the sharpness loss is due to lens choice,the first illustrates the
dangers of underexposing a high ISO image.
Aperture is by
and far the most powerful of the three choices. Opening your aperture
from 8 to 2.8 is a full three stops. This is the same as going from ISO
200 to 1600, or 1/1000 to 1/125. There are some downsides to large
apertures. Large aperture zoom lenses are expensive and heavy, because
it takes a lot more glass to let in all the light. Another downside is
that on many lenses the largest apertures are not as sharp and lose
contrast. As a rule of thumb you can't shoot low light kayaking with a
cheap zooms and get great results.
Option #1 is to lower your
standards and shoot high ISO speeds with cheap light zooms.
Option #2 is to buy expensive
fast zooms, but they run around $1,500 and weight as much as
3lbs. Plus 2.8 isn't really that fast.
Option #3 is the route I have
gone. Trade away the convenience of a zoom for the light weight and
(often) cheap cost of a "prime" lens. Prime lenses have generally been
in production a long time and are light and simple since they don't
zoom. The $120 50mm 1.8 is a great example. Over one full stop faster
than the $1,700 24-70mm 2.8, 1.7lbs lighter and $1,600 less! The
downside of shooting primes is the hassle of changing lenses on a
regular basis, and more hiking to get the shot you want. Sometimes you
just can't get where you'd like to be too. They are especially tough in
a rainy environment, where you don't want to expose the inside of your
camera body while changing lenses.
Nikon D200, Nikkor 50mm 1.8 @
1/500 F1.8 ISO 250.
The final problem
with low light kayaking shots is white balance. Ever notice how most
dark weather kayaking shots look "cold"? That's because they have too
much blue in them, even the best of cameras' Auto White Balance (AWB)
is not perfect. As always we have a few option to remedy the problem.
The first is to use a preset white balance that is built in. Shooting
on a cloudy day? Hold down the WB button and rotate the command dial
until you get to the cloud symbol. The downside to this method is that
it's not completely accurate as not every cloudy day is the same.
White Balance set to cloudy on
a Nikon D50.
The second is to
leave the camera on AWB and adjust while post-processing. This works
well with high end cameras that gets it right 90% of the time, but with
a camera like the D50 I found myself adjusting nearly every shot, way
too much work.
Third is setting
manual white balance with a gray card. Judging from my love of doing
things the hard way (manual exposure and prime lenses) it seems like
this would be right up my alley, but it's not for two reasons.
A. It's simply too much work
to set manually for every shot.
B. It's impossible to stand in the location of the actual shot to get a
true white balance, and the lighting on shore is often different.
With the D50 I used the camera
presets. With the D200/700 I use the AWB and adjust in post processing.
You'll have to judge based off of your camera's AWB abilities.
To sum it up with a few rules
of thumb: Adjust to your slowest acceptable shutter speed &
largest aperture before raising the ISO. There is a fine line between
lens performance at maximum aperture and ISO degredation. For example
on the Nikon D200 I'll bump ISO from 100 to 200 before taking the 50mm
from 2.8 to 1.8, because the ISO boost effects quality less than the
limited depth of field and loss of contrast seen in the lens at 1.8.