Tips for Aerial Photography from Electric Park Flyers using Micro Digital Cameras
version 21 dated 23 Dec 2004

General

Before you even start, think about the mission.  Remember the old adage of PPPPP (Prior Planning Prevents Piss Poor Performance).  Get it sorted out on the ground before you takeoff.

Until you get some experience, don't even bother to fly a sortie without bright sun and low wind.

Subject Matter

Before you fly, think of an interesting way to frame a shot.  A boring subject on the ground is still boring when viewing from the sky.
[Credit: Caveman]  One thing to remember about  aerial photos, they really "flatten out" terrain elevation changes. [Credit: Steve Nolan]

Reset

Once in a while, these inexpensive cameras "lose their minds".  In this situation, you need to RESET.

The Mustek camera has a small hole just above the On/Off switch.  Turn the camera On and then just poke a soft object such as a toothpick into the hole to reset it.

For the Aiptek, refer to page 30 in the manual... bottom of the page... real small print..  (2) Hold down the mode button until the LCD displays "888". Press the shutter button, and the camera will reset.  [Credit:  Sparky Paul]

Optimizing Focus

The typical Aiptek and Mustek cameras may need some work on the focus.  Optimizing the focus setting will radically improve the photo quality. Very tiny changes in the focus ring position can have a dramatic affect.  For sure, all the blurry background issues can be eliminated.
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For the Mustek camera, start full clockwise (infinity detent) and then snap photos every 5 degrees (yup, that is a tiny amount) up to about the mid-focus position.

Snap the photos of EXACTLY the same scene, which needs to include some highly detailed items, like trees or telephone poles, in the far distance. This is important.

Plug the camera into the PC and review each photo at 100% or larger zoom. The one with the best far field focus wins.  In cases where you cannot tell which is the sharpest, look at the photos' file sizes.  If the photos have the exact same background, then choose the focus corresponding to the largest file size. If the photos do not have identical backgrounds, then do not compare file sizes.

Once you identify the best far view focus position these little cameras can achieve stunning photos. [Credit: Mr. RC-CAM]
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The Aiptek appears to have the lens tube assembly preset to some nominal focal length at the factory. On some cameras, this preset position can be off by as much as a full turn so a manual re-adjustment of the lens tube is necessary to get optimum results.

Over 80% of the cameras require a tweak in the positive (towards infinity) direction, upwards of 1/2 turn on average.

This requires you to open up the camera and reset the lens tube to focus ring relationship. Taking shots while you adjust the lens a 'click' (equivalent to one notch on the lens tube) at a time.

At some point, the image file size max's out.  Zooming in on a section of that photo will reveal a distant object that's either 'pixelated' or 'defined'.

[Credit:  Wild Moose]

If an Aiptek is really messed up, then you should remove the lens barrel and count backwards about 7 to 9 full turns.

If your lens barrel is a loose fit (about 75% of the Pencams are like this), simply use a very tiny dab of rubber cement or silicone caulk on a couple of threads to provide some interference, the lens will turn smooth as silk.

Here is a great trick to use when in the field.  Pre-focus by simply doing the following, no laptop/computer connection is necessary.

Dial the camera to infinity then open it up and offset the focus ring 50% (midway between close-up and infinity).

Assuming you tend to redial in focus in the infinity direction, adjust the focus ring one 'click' (equivalent to a single notch on the inner lens tube ).

Point the camera so that you have 50% sky and 50% ground. This ensures consistent 'metering' by the camera. Try to avoid general outdoor scenery with trees and shrubs as these are too complex an image and will vary greatly from shot to shot if you do not aim with a tripod and have consistent lighting.

Snap as many shots as the camera will take without an SD card in it (very important!). Note how many shots you can take before the camera yields multiple beeps, this indicates that the built-in SDRAM is full.

Advance the focus ring one click and repeat.

At some point, you will notice that the camera will take less shots. This is the clue! Remember, well focused images have larger file sizes for the same image/lighting conditions. So by taking less shots before the internal memory buffer is full you will know you are very close.    Using this method you will be within 80%-90% of 'dialed in' depending upon the complexity of the image taken.

If the number increases, usually you will know this by about the third iteration. Simply reverse the direction of the lens adjustment.

[Credit:  Wild Moose]

Another method to tweak the Aiptek focus is described as follows.  Turn the focus ring all the way in one direction till it stops. Take a fine tip marker and make marks around the focus ring on the camera body: use the ribs on the focus ring as reference. Mount the camera on a tripod and find an open space where you can aim the camera at a distant object, preferably with an equal amount of sky and ground. Aim the camera at your target and snap a photo, then rotate the focus ring one mark (or if you really want to get picky, move the focus ring till the arrow points between the mark you just used and the next) and take another shot. Do this until you've moved the focus ring all the way around until it stops again. Go home and upload the images to your computer and look at the file sizes. A picture that is in focus has more detail than one that is out of focus, and the more detail a picture has the larger the file size will be. Just look at your pictures file sizes and the largest one will be the one that has the best focus. Count the number of pictures until  you get to the one with the largest file size, then set the focus rings to the same number of marks and you will be in focus.

[Credit:  tgrover]

Altitude, Distance and Look-Down Angle

You should know the field of view of the camera.  Do some test shots on the ground.  Measure out one yard and take a shot of a yard stick 90 degrees to the camera.  Upload the photo and read off the distance from centre.  Then get out your trig tables and compute the angle.  Use the tangent tables - the opposite over adjacent.  In this case the opposite is the distance that the camera "saw" and the adjacent is one yard.  For the Mustek Mini 3, the field of view is 34 degrees.

Work up a spreadsheet on your computer so that you can tell how far back you have to be from a target to get in its total width.  Then work out the height you have to be for the given look-down angle.  Then add 25% extra and you should get a shot.

Assuming you are doing anything other than vertical shots, the look-down angle should be adjusted on the ground.  If you intend to do distance shots of the far horizon from maximum altitude, then a look-down angle from the horizon of about ten degrees is correct.  Equally, if you want to fly low and get a "heads-up" shot, the ten degree angle still works.  But, it the middle altitude range, you probably want the camera to look down as much as 45 degrees.  Some pilots use a system of different holders for each scenario, others use hinged or swivel arrangements.  The simplest when you start out may just be a series of balsa wedges that you use as shims between the camera and the plane.

Test

Plug in your camera and test the trigger on the ground.  Consider securing the connection - something like half a reef knot, plug in male/female parts and draw tight.

Wind

You want to fly into the wind to keep the over-the-ground speed lowest to minimize motion blur.  Put the camera on the side that points to the target when flying into wind.  Put a 12 inch length of yarn on the tip of your antenna so that you can judge wind direction easily.

Sun

You want the sun to illuminate the target.  Best is directly down sun but up to 90 degrees to the side will work.  Do not try to shoot into the sun unless absolutely unavoidable - the colors will be all washed out and you will get lens flare.  Wear a cap so that the visor will shield your eyes from the sun.

Dogs

Dogs that are running loose off the leash on your "airfield" provide an unusual hazard.  Some breeds see the light craft that we fly for AP as an easy meal to be grabbed out of the air as we land.  Scan your surroundings before you take off.  It is helpful to have a co-pilot to make dog owners in the area aware of the problem.

Power

Once you have lined up the target, cut the power and trim for the glide.  Wait until the propeller stops wind milling before you trigger a shot.  Shoot as many as possible while in the target zone.

Camera Orientation

Do you want the camera to point straight ahead or should it look to one side or the other?

With a tiny & cheap camera, pointing straight ahead isn't really a problem. Otherwise, usually:

*  the camera is in front of the CG so you need to replace it with ballast if you fly without the camera
*  the camera is on the front of the plane, so if you crash it's going to get smashed
*  the lens is liable to get stuff on it (bugs, dust, water, etc.), both in flight and on takeoff/landing

[Credit: Bill Glover]

You could point the camera to the side for a few reasons:

* the side of the camera is usually slimmer presenting less drag
* under the wing at the center of gravity, it's easier to balance the plane
* more protected in a crash
* easier to get the shot.

The last point is the main reason. If the plane is traveling towards the subject, you have a shorter moment of opportunity than from a side-circling shot. From a side shot, you can maintain a certain distance, opposed to a one-shot bombing run.

[Credit: rtideas]

Steady As She Goes

These cheap CMOS cameras take some time to dial in the correct exposure. The best way to get the camera to the right exposure setting when shooting in bright daylight is to fly a straight line in relation to the sun for about 10 seconds or so then snap the picture.

Every time you turn the plane, the camera has to recompute the exposure and that takes a bit of time. The best way to get a feel for this is to attach the camera to a portable computer and slowly turn in a circle. You'll see how long it takes to stabilize the exposure when moving from dark to light and back again.

Flying slow large squares works very well for 45 degree down angles from horizontal. At 10 degree down, avoid shooting toward the sun and set up your flight line to provide a settling in time for exposure before reaching your intended subject.

[Credit: ggunners]

Many Shots

Take as many photos as possible on each mission.  There is no way of knowing whether you got the target framed properly, so more shots increases the probability of getting it right.

Binoculars

Binoculars could be invaluable to help you determine a high flying  plane's orientation.  But, it cannot be stressed enough the danger of accidentally looking into the sun through binoculars. Even if it doesn't cause lasting damage that hurts for hours or days, you may not be able to see clearly for minutes after exposure to magnified sunlight. [Credit:  Kinnic^2]

That having been said, binoculars can help you if you have to fly close to the sun to get into position - the narrower field of view helps blocks the sun.
But, consider this an emergency measure only.  It would be much better if a friend helped out with the binoculars if you have to fly close to the sun.
It is best to use binos that have a low magnification power and wide field of view. [Credit: Arp]

Note:  If you use the binos yourself, you should have your transmitter on a neck strap so that you can use one hand for the binos and one for the transmitter.  Equally, the binos need to be on a neck strap.

Timer

Get a small timer to attach to your transmitter. Time your battery endurance on the ground.  Fly about 75% of your pack's time and then start looking for a landing spot.  Always keep that battery reserve so that you can go around if the landing approach is bad.

Flying Tips

Always launch and land into the wind.  You need to get the maximum airflow over the wing for the minimum ground speed.  Equally, just as you launch and land, the airplane is at its slowest and roll control is very hard to maintain.  You want the minimum side forces trying to tip the plane in this critical phase.

You'll have better luck gaining altitude if you fly into the wind.

Try to keep the plane upwind of your intended landing spot until you are sure you will make the Landing Zone (LZ).  As the battery fades, it gets harder and harder to fly into the wind.

If you need to lose altitude in a hurry, resist the temptation to just push the stick forward to get into a dive.  The flimsy electrics we are using for AP can easily set up "flutter" that can destroy a major component in a matter of seconds.   Instead, put the plane into a spiral dive by pulling full UP elevator and pushing the rudder hard over to one side - hold both at full deflection.  The plane will go into the spiral dive and lose altitude fairly quickly but will not pick up speed.  To recover, neutralize the controls.  Change underwear as required.

It is virtually impossible to set up the perfect dead stick landing approach.  If you are slightly low, you can add a bit of power and pull the plane into the LZ.  If you are a bit too high, it is better to bleed off height by gliding in a power-off "S" pattern than having to go around for another circuit.

If you do have to fly in wind, keep in mind that a Slow Stick flies at a mere 5 mph and that 12 mph winds are as much as even an expert pilot can handle [Credit:  Kinnic^2]  A SoarStar can handle higher winds but gets swatted to the ground in 20 mph gusts.

Posting

If you post to a web-based forum, you will inevitably be asked about your plane and the camera that produced the masterpiece.  You could store this information in a text file and then cut and paste it into your posting message.

The plane part usually breaks down to the following detail:   Model Name, Motor, Gearbox, Propellor, Battery Pack:

Example:  Slow Stick, GWS 300, GWS 6:1, 10 by 4.8, 8 cell NiCad 600mAh

The camera information should include: Model Name, Full Frame Resolution, Memory/Storage Capacity, Shutter Trigger

Example:  Mustek GSmart Mini 3, 1600 by 1200, 16 meg, Mr. RC-Cam

You might want to add any detail about software used to 'enhance' and/or reduce your image.

Example: MGI PhotoSuite4, reduced to 640 by 480

[Credit:  Kinnic^2 and Flattire]