Keeping
our
expose to the right rule in mind, let's move on to deep, dark canyons
and rain fed rivers. Sometimes they have the most epic scenery but can
be hard to photograph well. When there
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
blur).
Here the paddler
is nice and
crisp both the paddle blade and splashes make it feel soft overall. Nikon D200. Nikkor
18-200 @
70mm 1/500 f/5 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 spent on a camera can make a big difference. If you are
shooting at your camera's base ISO you have quite a bit of flexibility
to adjust the exposure on a computer after the fact. In darker light
make sure not to under-expose a high ISO shot. At high ISO any noise is
greatly magnified if you adjust
the exposure, and this can ruin the shot.
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 seen at 100%: ISO: 800, Post
production +2.5
exposure
ISO:
800, Post production
+.25 exposure.
Although
a little bit
of the sharpness loss is due to lens choice,the first illustrates the
dangers of underexposing a high ISO image, look at the colored noise on
the dark rock wall.
Aperture
is the most
powerful of the three choices. Opening the 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 that 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.
I see three basic routes that can be taken for photographing kayaking
in darker conditions.
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 $1,800 and weight as much as
3lbs. Plus 2.8 isn't really that fast.
Option #3 is prime
lenses. Trade
away the convenience of a zoom for the lighter weight and
(sometimes) cheaper cost of a prime. Prime lenses have often been
in production a long time and are light and simple since they don't
zoom. The $120 50mm f/1.8 is a great example. Over one full stop faster
than the $1,900 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 @
1/640 F1.8 ISO 320.
The
final problem
with low light kayaking shots is white balance. Ever notice how most
dark weather kayaking shots look "cold"? That's because when the sun is
not shining there is a lot more blue light still present. There are of
course a few options to remedy this problem.
I strongly suggest shooting in raw and dealing with white balance
issues later, and skipping the below. If you insist in shooting jpg,
read on.
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. Same for sun or shade as there is a
setting for each. The downside to this method is that
it's not completely accurate as not every day has the same exact
balance of light.
If you're really a
masochist, it's
possible to set set
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.
To
sum it up with a few rules
of thumb: First adjust to your slowest acceptable shutter speed
& next to
largest aperture before raising the ISO. There is a fine line between
lens performance at maximum aperture and ISO degradation. For example
on the Nikon D200 I'd move the ISO up from 100 to 200 before opening
taking the 50mm
from 2.8 to 1.8, because the ISO at 200 is less detrimental to optimal
capture than shooting the 50mm at 1.8. White
Balance set to cloudy on
a Nikon D50.