2. Shutter Speed & Aperture
In aerial photography, the subject is almost always at "infinity."
So depth of field is rarely a consideration. However, the camera is moving through
the sky at more than a mile a minute, so motion-freezing shutter speeds are
important, especially at lower altitudes.
For most aerial work, you want the fastest possible shutter speed,
to offset the motion of the airplane (and camera), especially
at lower altitudes. This shot was made with the camera pointed
straight down at the ground for a vertical viewpoint. Remember
to shoot some vertical-format images, too--don't shoot
everything in horizontal format.
I shoot wide-open in aperture-priority AE unless except in cloudy conditions
where the sun might suddenly come out--the camera's fastest shutter
speed won't be fast enough to avoid overexposure with the lens wide open.
For example, at ISO 400 (which I use for cloudy weather), the proper shutter
speed for bright sun at f/2.8 would be 1¼12,500. In such conditions,
I either closely monitor the light level, or switch to program AE mode. (Action
mode would provide the fastest possible shutter speed for a given light level,
but doesn't permit use of exposure comp, and I frequently use that--for
example, most SLRs tend to overexpose greenery.)
A fast shutter speed is especially important when photographing
nearby objects like clouds--even if you hold the camera perfectly
steady, you are moving past the object at more than a mile a minute,
and a slow shutter speed will blur it. Tip: Fly toward such subjects
at an angle, rather than trying to shoot them when they are directly
to the side--the relative motion will be less, and your chances
of a sharp shot that much greater.
3. Focal Length
I like focal lengths from 28mm to 135mm for aerial photography (not coincidentally,
I have a 28--135mm zoom lens). With wider focal lengths, it's hard
to keep from getting some part of the camera plane in the shot; with longer
focal lengths, it's hard to get sharp results due to camera shake (my
28--135 has a built-in image stabilizer). Sometimes it's nice to
use a really wide lens and deliberately include a wing as a graphic element,
but generally it's best to shoot "clean" aerial photos. With
the "affordable" digital SLRs and their smaller-than-full-35mm-film-frame
image sensors, any lens will have a narrower angle of view than it does on a
35mm SLR--my 28--135 frames like a 45--216 when used on my digital
SLR with its 1.6X "crop factor." This still provides a good range
of focal lengths for aerial shooting, but I also have a wide-angle zoom lens
I use on both film and digital cameras.
Sometimes a lens outside the 28--135mm focal-length range
comes in handy. It's a bad idea to fly near fires--smoke,
turbulence and firefighting aircraft present hazards, and TFRs
(temporary flight restrictions) make it illegal. This image was
cropped from a shot made with a long image-stabilized lens from
well clear of the fire area.
Why zoom lenses? Because it's a lot easier to rotate or slide a zoom
ring than it is to change altitude hundreds or even thousands of feet to get
the desired composition. Most pro aerial photographers work at lower altitudes--500--1000
feet above ground--because shooting from lower altitudes provides a more
dramatic perspective (the higher you shoot from the flatter everything looks)
and reduces the amount of atmospheric haze between camera and subject, but I
also shoot a lot of images while en route to destinations, at much higher altitudes.
Those perfect moments when camera angle and lighting are just right are fleeting.
Keep your eyes open, and when you see something good, have the pilot circle
it, so you can get several chances at that perfect moment.
If you see something interesting, have the pilot circle it, so
you can shoot from several angles, and get more than one shot
at the best one. Be sure to keep the horizon horizontal, even
if it doesn't appear in the frame. If you tilt the camera
around the lens axis, the ground surface will look "off"
and make viewers of the image uncomfortable.
5. Fear Not...
If you're afraid of little airplanes, you can still get some "aerial"
photos by shooting from hilltops or tall office buildings. This also provides
the advantage of a stationary camera, allowing you to study your compositions
carefully before shooting, and you can get sharp images in dimmer light by attaching
the camera to a tripod and making longer exposures.
Next Month: Telephoto Lenses