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Whitewater Photography Tutorial #5: Focus.
Another make or break it component to any action shot is a
getting a good focus. Digital cameras focus best on areas with straight
lines and high contrast, not exactly the prime feature of whitewater.
Big water can be exceptionally tough.
This is an area of photography where Canon has been far
ahead of Nikon until the D700 and D3 which have made considerable steps
forward. Being a Nikon shooter all my comments will be based towards
these cameras, especially my D200 workhorse. The more expensive the
camera, the better and more confusing the AF system gets. I'll try to
keep it relatively simple here.
As a side note I have used some third party lenses, but have found that
in general they miss focus more often. In some cases like the Sigma
18-200, there is an incredible rate of back focusing.
Nikon D50, Sigma 18-200 @ 116mm. 1/1000 F6.3 ISO 800. Note how
the rock and water in the background are in focus while the paddler is
blurry.
But it's just not third-party lenses. Nikon D200, Nikkor 18-200 @ 95mm. 1/800 F8 ISO 200.
Shooting with longer lenses:
On many cameras the center sensor is the only truly reliable one, which
is a shame since we rarely, if ever, want the paddler in the center of
he shot. One of my favorite tricks is to focus on an object (rock or
tree) that is the same distance away as the paddler will be, then
recompose my shot on the rapid.
This works on Nikons all the way down to the D50, and I
assume it would on Canons too. First turn your auto-focus mode to Auto
Focus Continuous aka AF-C. If it's a lower end camera then through the
menu system turn your AE-L/AF-L button to "AF-ON". This disables the
button as Auto Exposure Lock but removes focusing from the shutter
release. Now when you want to focus you use the AE-L/AF-L button
instead of the shutter release.
Shot using the "longer lens" method. Nikon D200, Nikkor 50mm 1.8 @ 1/1000 F3.2 ISO 100.
Higher end cameras have a dedicated "AF-ON" button.
Through the menu system you have to turn off the shutter release from
activating AF. Now the shutter release is just that, and the AF-ON
button us used when you want the camera to focus. On both make sure
you're set to continuous AF because it is more accurate, and once the
AF-ON button is released, your focus is set. AF-C also ties in nicely
to the next piece of AF advice.
Focusing with wide lenses:
Missed up close focus. Nikon D200, Nikkor 20mm 2.8 @ 1/1000 F3.5 ISO 100.
Focusing with wide lenses is easy if the object is over
five feet away, because if you have a relatively large aperture,
everything past five feet is in focus! Of course this is rarely when a
wide angle lens will look good. It's not about "getting it all in" with
a wide angle, it's about getting close to your subject; the paddler. In
the above shot I missed the focus trying to use the "longer lens
method" of focusing but estimated my distance poorly. Nail that focus:
Standing in the same shot with the same exact specs, but using a
different method of focusing.
When shooting up close I'll look through the view finder and format my
shot, noting where I expect the paddler to go. I'll then select that
focus area and make sure the camera is set to "Dynamic Area AF". Then
I'll do one of two things. If I know the exact composition I want, and
that it will be hard to get perfect again, I will compose the shot,
keep the AF-ON pressed down and wait for the paddler to come into the
frame. If I am not as worried about the composition and just want to be
sure the paddler is in the right spot, I'll focus on them in the lead
in and keep the selected AF sensor over them (and on) while following
them through the drop, taking a shot (or sequence) when they are close
to where I want them.
While not easy to explain, these two methods should help you achieve a
better ratio of in focus shots.
Next up: Basic lighting.
Whitewater Photography Tutorial #1: Intro
Whitewater Photography Tutorial #2: What is the right exposure?
Whitewater Photography Tutorial #3: Getting the right exposure.
Whitewater Photography Tutorial #4: Low Light Action
Whitewater Photography Tutorial #5: Focus
Whitewater Photography Tutorial #6: Basic Lighting
Whitewater Photography Tutorial #7: Composition
Whitewater Photography Tutorial #8: Gear Picks
Whitewater Photography Tutorial #9: Post Processing
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