Aerial Photography

Take Your Best Shot

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Potowat Indian Health Village Clinic 

Photographs of buildings often benefit from slanting light. In this case, I knew that late afternoon sunset would highlight the view of the entrance to the new Potowat Indian Health Clinic north of Arcata, California.

Since long shadows are projected backwards, no important details are obscured, but the shadows give a feeling of depth to the photo. Minimum flight altitude over populated areas is usually 1000 feet, so a moderate telephoto lens helps fill the aerial photo frame.

Planning
Equipment
Optional Equipment
Setting the Camera
Flight Path
Shooting the Photographs
Photographing From Commercial Airliners

OBJECTIVE

With aerial photography, like most photography, you want to take a well-composed, sharp photograph of the intended scene, your photographic “target”, without distractions or confusion. Here is how to do that.

PLANNING

Do your planning on the ground. Believe me, after a few hundred hours of aerial photography, I know for a fact that it is ten times easier to plan on the ground than in the air!

First, know the objectives of your aerial photo project; in other words, what is your target? Things look a lot different from the air, so work on the identification of your target: study maps (air, road, topography), get landmarks in mind, take GPS (Global Positioning System) readings if you can, ask pilots for help. In other words, do everything you can that will help you to find your target from the air. You may have driven up your own driveway for twenty years, but there’s no way to read street signs from a thousand feet and none of the usual landmarks look the same, either.

Consider the lighting you want for your photo. If the photo requires lots of overall detail with little emphasis on aesthetics, then midday lighting is best. With the sun up high, shadows are at a minimum. Overall the lighting effect is rather flat, but not much detail gets lost in dark shadow. In fact, a day with a high and evenly-spread cloud layer can work, as long as you don’t need an altitude higher than the clouds. If you’re looking for a more beautiful photograph, then the lower slanting light of morning or late afternoon gives a dramatic look from the air. Analyze which sun angle you want on your target to plan for the best time, within limits, of course. A client once asked me for a photo of the south-side front of his building, and he wanted the sunset behind it, to the north. I can afford to wait for good weather for an aerial photo, but would have to wait a long, long time for a northern sunset!

The format for aerial photographs can be either vertical or oblique; vertical photos are shot exactly straight down - a fairly technical assignment - so this article will discuss just the oblique photo which is shot at an angle to the ground, much like looking out from a hillside to the valley below. Oblique aerial photos come in two formats: one format includes the horizon at the top of the photo, the other doesn’t.

North Coast Lagoons Clouds

When shooting an oblique view that includes the horizon, be extra careful to keep the camera level with the horizon. If the airplane is in a banked turn, avoid the tendency to orient your camera with the aircraft instead of the world outside. Also, unless clouds add interest to the composition, you don’t need very much sky, so don’t “aim” at the horizon as the center of your photo.

Geography along the Pacific includes Redwood Creek at the bottom of the photo, then Freshwater Lagoon, Stone Lagoon, Big Lagoon and Patrick's Point. Recent rain storms provided a brown, silty texture to the ocean.

North Coast Lagoons Clouds

When shooting an oblique view that includes the horizon, be extra careful to keep the camera level with the horizon. If the airplane is in a banked turn, avoid the tendency to orient your camera with the aircraft instead of the world outside. Also, unless clouds add interest to the composition, you don’t need very much sky, so don’t “aim” at the horizon as the center of your photo.

Geography along the Pacific includes Redwood Creek at the bottom of the photo, then Freshwater Lagoon, Stone Lagoon, Big Lagoon and Patrick's Point. Recent rain storms provided a brown, silty texture to the ocean.

 Before the flight, establish the best possible communications with your pilot - get on the same track. Study maps together, discuss air speed, headings, and altitude. If possible, a previous aerial photo of the same area can be of great help. During actual photography from the air, agree ahead of time that you will give directions for the flight on everything that does not compromise safety. I can’t ever recall having overdone preflight planning with a pilot.

You are completely responsible for the preflight check of your own equipment. Be sure lenses are clean, film or digital cards/batteries are loaded, and lens hood and filter are firmly attached. In short, make sure all of your camera equipment is working. Some additional concerns for your aerial photography preflight include:

Tape your lens focus at infinity or apply the infinity setting to your digital camera if possible.

Tape down knobs, such as shutter speed or settings dials. In the noise and sensory overload conditions of an airplane cabin, it is surprisingly easy to bump knobs or other settings on your camera and not notice.

Use a haze filter to help remove some of the blue cast that comes from shooting through a lot of atmosphere. Also, a polarizing filter can increase contrast and give very pleasing results at certain camera angles and times of the day. If you’re just starting out though, twisting that filter while trying to maintain the target in your viewfinder is just one more detail in an overloaded work environment. Especially in the beginning, keep things as simple as possible.

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Boardwalk with Boat

Late evening light calls for a combination of fast film and fast lenses. The extra dollars spent on a quality lens pays off when you can confidently use the lens at its widest aperture and still use a fast shutter speed.

There is no need for depth of field in aerial photography; just tape your lens focus at infinity and use the widest f-stop. If you don’t have a professional lens, for sharpest photographs, adjust the lens about two stops from its widest setting, as long as you can keep the shutter speed at 1/500th of a second or faster.

Of course, it always helps if a boat shows up at just the right time to reflect the glowing sunset in its wake, here along the Boardwalk in Eureka, California.

EQUIPMENT

A quick and simple checklist of the minimum you need to take aerial photos:

Camera—film or digital, 35mm is fine unless you want the bigger enlarement options of a medium format film

Lens—zoom is ok if it is a professional lens; high quality at low cost can be obtained with fixed focal length, such as 50mm or 90mm lenses

Camera strap—keep that strap around your neck! A loose camera out the window is both expensive and dangerous.

Film and/or Digital Supplies—Slow speed film (50-100 ISO) for midday sunlight or if you have a fast, professional lens; Medium speed (200 ISO) for point-and-shoot type cameras or cloudy bright conditions; Fast speed (400+ ISO) for low light or if you won’t enlarge prints much beyond 8x10”. Take two to three times the film you think you’ll need. For digital, take a spare digital card or two, plus plenty of batteries. Battery life is significantly reduced with cold temperature, such as from the open window of an airplane.

Aircraft—most airports have flight instruction and rental operations that you can hire. Many have introductory flights at a reduced rate and won’t mind you bringing along a camera. Cessna airplanes are readily available and make a good camera platform because of their high wing and windows that open.

Pilot—I have flown in the past as a pilot. For aerial photography, I have thought about piloting again, briefly. However, I am primarily a photographer, which is job enough up in the air. So while I concentrate on getting the best possible aerial photograph, I leave the best possible job of flying, navigating and safety to the pilot. It’s a good combination and always adds a comfortable level of safety while in the air. Occasionally I get to take the controls while the pilot sets the GPS or consults the map for the next target. But we each have our specific focus that works well to get the job done. Pilots of U-2s and SR-71’s might also be taking the recon photographs, but they have a few million dollars of autopilot, radar and automatic camera equipment to back them up. Lacking that, I prefer the assigned duties covered by two people – one pilot and one photographer. Aircraft rental companies will often provide a pilot, usually an instructor. Don’t be shy to ask how many flying hours your pilot has or how familiar he is with the local terrain. An experienced pilot with whom you can easily communicate is your best asset for aerial photography.

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Eureka High Altitude

On exceptionally clear days, aerial photography from high altitudes can give seldom-seen perspectives of an area. On a winter day from 12,000 feet over the Pacific, we could see from Eureka, California all the way to Mt Shasta, 100 miles to the east. This high up, a haze or polarizing filter definitely helps, and so does an oxygen bottle! Dress warm and wear gloves – even with the Cessna 182 window open for just a minute, it got cold in a hurry.

Remember that smaller planes can take a long time to get this high, too. Ask your pilot about airplane climb rates (vertical feet per minute) as well as hourly rental rates, and factor in the increased aircraft rental cost for taking aerial photos at high altitude.

OPTIONAL EQUIPMENT

Spare Camera—don’t waste an expensive flight and all that time if something goes wrong with your camera. Take a spare on every flight!

Haze and Polarizer Filters—filters help to cut the blue cast and increase contrast, especially at high altitudes.

Lens Hood—Also helps to increase contrast and avoid lens flare when the aircraft wing is not shading the camera from the sun.

Electrical tape—seems like up in the air, there is always something to tape down. On your camera, electrical tape removes easily without leaving a sticky residue. Duct tape works, too - I usually have several small pieces already cut and sticking to parts of my camera bag.

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SETTING THE CAMERA

Exposure—For manually setting the camera, the “Sunny 16” rule works well for most hours of a sunny day in the air. That rule says to set your lens f-stop to f16 and your shutter approximately to the film speed. For example, with 100 ISO film, your setting is f16 at 1/125th second shutter speed. Of course, 1/125th is too slow for aerial photography, so swap f-stops for shutter speed, e.g., f11 at 1/250th, f8 at 1/500th, f5.6 at 1/1000th and so on. I consider 1/500th the slowest handheld shutter speed and prefer 1/1000th for aerial photos. Remember, the airplane is vibrating, the ground is moving, and, often enough, you’re shaking.

In conditions other than blue-sky sunshine, before takeoff, take a light meter reading on the ground, either an incident reading by pointing the meter up toward the sky or a reflected reading using neutral gray such as the runway cement or a neutral gray card if you remember to bring it. Then set your camera accordingly.

The light exposure reading from the air can usually be trusted over mixed terrain if you are at low altitudes. Over 2000 feet, depending on atmospheric conditions, your camera’s built in meter can give worse exposure readings than what you measured on the ground. When in doubt, bracket exposures. I prefer transparency (slide) film and usually bracket one stop under and over the selected exposure. Over a dark forest or a bright wheat field, your camera’s reflected exposure reading can be off by a stop or two, so trust “Sunny 16” or your on-the-ground meter reading.

Once again, you don’t need depth of field at 1000 feet or more above the ground. Try to find the “sweet spot” where your lens has its best resolution and then use that f-stop with a film speed and shutter combination that allows you to shoot at 1/500th or faster.

Whether auto or manual exposure, get out the tape and stop those camera dials from moving. If it can move, tape it down! I’m amazed at how a camera seems to have a mind of its own in the air and ends up on settings that I never intended.

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Humboldt Bay Entrance

Be on the look out to add interest in your aerial photo. Seeing this freighter approaching the entrance to Humboldt Bay, I directed my pilot to get the proper perspective as the ship passed the jetties on either side. Pilots usually enjoy the assignment and “mission” aspects of aerial photography – just give clear directions regarding speed, altitude, and heading, along with an occasional please and thank-you. In this case, thanks very much to the U.S. Coast Guard aircrew, who gave me one of the best views of-the-world in-the-world out the open door of a Dolphin HH-65 helicopter.

 Lens Focus

Unless you’re in a helicopter flying very low, flight rules will keep you at 1000 feet or higher for most aerial photography. For all intents and purposes, that’s infinity on your lens focus. So tape your lens barrel at that setting. I guarantee that if you don’t, you will come home with out-of- focus pictures because the lens changed focus due to vibration or bumping or whatever airborne gremlin it is who delights in twisting that barrel!

If your lens is autofocus, the camera may have trouble focusing on the rapidly moving earth beneath you. Best approach is to set it to manual focus and just tape it down (have I mentioned tape before?). Some point-and-shoot type of camera are really deficient at focusing on moving objects – if your camera does not allow a manual focus setting at infinity, you might want to test it from a moving car first to see how the autofocus acts on distant objects out the window.

Lens Focal Length

For many years, I have done 95% of my aerial photography with fixed focal length lenses (also called prime lenses) of 35mm, 50mm and 90mm on my 35mm Leica M6 or with corresponding focal lengths on a Hasselblad 6x6cm. Once in awhile a telephoto of 200-300mm on an 35mm SLR would be needed to isolate a single house from the air. Zoom lenses that cover some part of the 28-200mm range are useful and handier than prime lenses. However, high quality zoom lens with fast f-stops are expensive. You get more bang-for-the-buck with prime lenses. If you need to zoom, just ask the pilot to “go ‘round” again a little closer or farther away.

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Arcata Marsh

If the oblique aerial photograph does not include the horizon, use other landmarks as references to make the picture level. The electrical towers provided the vertical comparison. Another way is to temporarily raise the camera to include the horizon, establish “level”, and then tilt the camera perpendicular to the horizon. Tight cropping here ensures lots of detail while still including all the prominent geography of the Arcata, California marsh and water treatment facility.

FLIGHT PATH

Typically to capture your target on film (or digital) you need a smooth, slow turn around the subject. If, for example, you are documenting a building, you could orbit the target, shooting every 45 degrees for eight shots total. Then climb a few hundred feet and repeat the process, maybe closer in to the target at a steeper angle to the ground. Even if you need a photo of only one side of your target, the orbit approach works well – just tighten up the turn. Use the wing as a reference to keep your camera aimed at the same angle out the window.

Speaking of windows, most Cessna aircraft have a window on the passenger (right/starboard) side that opens a few inches and then stops due to a bracket. That bracket is easy to remove, does not violate any flight regulations when removed, and gives you an unobstructed view with the window wide open and “flying” in the air stream under the wing. The wing strut and wheel will limit your overall angle of view somewhat, so watch out for them creeping into the corner of your photo. Don't poke the camera out into the windstream which will buffet the camera, cause even more vibration, and make it  difficult to track your target. In any case, make sure you can open the window wide. After all the money you spent on great optics, don’t cover up that image with the optical “gauze” of scratched plexiglass between you and the target.

Ask the pilot to give you a slow but safe speed to orbit your target. Don’t hurry. Line up properly. If you miss the shot, go around again. Most of your time (and expense) was spent just getting to the target anyway, so take your time with camera and positioning to get it right.

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SHOOTING THE PHOTOGRAPHS

Here is a checklist for actually taking the photo:

  • Safety—make sure your seat belt and camera straps are all in place.
  • Communicate with the pilot. Direct the flight. Pilots will override if safety issues.
  • Find target and set up the turn. Ask pilot to tighten or widen turn as needed.
  • Hold the camera steady. Don’t brace it anywhere that transmits vibrations. (Your “Seat & Feet” only should be in contact with the aircraft.)
  • Avoid edge of door, wing strut and landing gear in the photo.
  • Look ahead—remember the map and ground views of your target.
  • Compose:
      Hold the camera level left to right - no tilt (horizon for reference).
      Crop with zoom lens or “zoom the aircraft” if a prime lens.
      Fill the frame while maintaining relationships around the target.
  • Don’t stab at the shutter release (use rifleman’s technique - breathe and squeeze).
  • Get your sequence of shots.

If you think you missed something, you probably did - go around and shoot again – it’s much cheaper than having to redo the whole flight.

 


As a little reminder, think of doing your aerial photography with CLASS!

   Compose
   Level the camera
   Acquire your target
   Steady the camera (seat and feet, squeeze shutter)
   Sequence your shots

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PHOTOGRAPHING FROM COMMERCIAL AIRLINERS

Commercial flights can take you over some very beautiful country, with opportunity to shoot it. Conditions aren’t optimum and you can’t ask the flight attendant to see if the pilot could do a quick go’round. However, you can still get some good photos with some simple steps:

• Of course, ask for a window seat, but not over the wing.
• If the plane isn’t very full, look for a window seat with the least scratched window.
• Using the photo techniques described above, gently touch the lens to the plexiglass, and then back it off slightly so no aircraft vibration reaches the camera. Keeping the camera close to the window eliminates reflections and keeps optical distortion from the window to a minimum.
• Don’t use a polarizer – the plexiglass/filter combination gives odd colors.
• Especially look for good photos at low altitude while taking off or landing  (Get your camera out if your bag is in the upper storage - the seat belt sign is on during the most interesting low altitude part of the filight).

• At altitude, try using the little round window at the rear galley of some commercial airplanes – it is often fairly clean and scratch free.

Mt. Shasta from Jetliner

You can take good aerial photos from passenger jets, especially near the airport when you are at relatively low altitude. For Mt Shasta, I used the technique described in this article and had a good window seat in a U.S. Navy C-9 (same as the civilian DC-9) as we climbed out of the Redding, CA airport. The original digital photo had a blue cast, which was easily removed with the “Auto Color” feature of Photoshop.

GET STARTED

The complexity and methods of aerial photography can fill a whole book just for how to shoot oblique photos. Vertical aerial photography leads to even more complexity covered by topics such as Photogrammetry and Remote Sensing. But for getting started, the ideas in this article cover most of the basics and should help you with that unique pictorial perspective called aerial photography. Be safe and have fun.

 

Samoa Stitched Vertical

ABOUT THE VERTICAL FORMAT PHOTO: Shooting straight down on the landscape gives a perspective that can be helpful for planning or mapping. However, many people have a hard time understanding what they are looking at from the vertical angle. Also, for a hand-held camera, it requires some special aerial maneuvering to get the camera pointed absolutely vertical. I rely on a special camera mount in the airplane, which keeps the camera vertical while in normal, level flight, and also allows for a series of vertical shots that can then be scanned and stitched together with “panorama” software on the computer.

Since I am not actually looking through the camera viewfinder on vertical photo flights, careful preflight planning is also required. In this case, for proper ground coverage, I calculated altitude for the lens/film size combination, gave the pilot specific flight path information (GPS points, heading and speed to fly), and then took photos every 15 seconds as we traversed the Samoa Peninsula located between the Pacific Ocean and Humboldt Bay. The six photos cover about two miles on the ground as required by my client, an engineering company. The final digital photo was over 350 megabytes and clearly displayed detail down to the yellow stripes on the highway.

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Articles and photographs copyright Gary Todoroff. For licensed use, call (707) 445-8425 or contact him by email.