AERIAL PHOTOGRAPHY
by Ironsides
[Revision 26 dated 20 July 2003]

There are many expensive rigs that will allow you to take great photos from the air.   They range from fully stabilized platforms for full size 35 mm cameras  to the newer 2.4 gigaherz video down links [ http://www.supercircuits.com/ ] or [http://www.polarisusa.com/  ]

A most interesting recent development in the 2.4 gigaherz band is the additional of virtual reality goggles to a downlink video system.  This setup allows a pilot to "actually" fly his airplane.  Have a look at [http://www.wirelessvideocameras.com].

A more recent offering in the 2.4 gig band can be found at: [http://www.digicams-uk.com/category1_1.htm].  The RCGroups eZone forum really likes the Black Widow system that can be found at: [http://www.blackwidowav.com/]

You will find a very comprehensive site reviewing fixed and rotary wing still and video aerial photography at this Australian site
[ http://www.hicam.com.au ]. They provide a very interesting link to some excellent aerial photography can be accomplished using kites.
Kite on over to:  [http://arch.ced.berkeley.edu/kap/].

For the average user wishing to take photos from an RC aircraft, there are two inexpensive practical options.  First, there are new digital cameras and second the old fashioned 35mm formats.  While few will risk an expensive digital or 35mm camera, have a look at the following digital options.

DIGITAL from Electric-powered Park Flyers

A technical breakthrough has arrived in the form of the Aiptek Mini Pen Cam 1.3 meg chip ®, costing about $US 60.   This digital camera weighs in at about 50 grams without the required two AAA batteries.  [The Aiptek now comes as an SD version that permits the use of a 128 meg storage medium.]  Equally exciting is the arrival of the Mustek GSmart Mini3 ®, priced at about $US 90, which sports a 2.1 meg chip and a built-in lithium-ion battery that recharges through the USB port.  It weighs only 40 grams.  Both the Aiptek and Mustek cameras feature 16 meg built-in storage.
 

 
Both cameras are CMOS-based - this format has a problem with vibration in that wavy lines result as the image is written to storage.

These CMOS cameras work best when lifted by electric planes where the motor can be switched off, to eliminate most vibration, while the photo is taken and stored. 

The most popular planes are the Slow Stick (left below) and the Wingo (right below), both park flyers best suited to low wind conditions.  [The Soarstar is very similar to the Wingo.]

Photos below by Richard Ingram:   http://webpages.charter.net/ringram2077/picprojects.html


Aiptek 1.3 on Slow Stick pointing straight down                                                                         GSmart Mini 3 on Slow Stick aimed obliquely

 While the cameras can be triggered with micro servos, most recently electronic switches that plug directly from the receiver into the camera have been developed.  Any detail on technical advice available on "How to.." is contained in the links below each photo.

                                           GSmart Mini 3 with Mr. RC-CAM switch                                                                                           Michele Schiepatti GSmart Mini 3 switch
                     http://www.rc-cam.com                                                                            http://www.rc-flysoft.com
 

                                           SMT Switch by Wild Moose                                                                                                         GSmart Mini 3 switch by Richard Ingram
         http://home.att.net/~mechconsultant/wsb/html/view.cgi-home.html-.html                               http://webpages.charter.net/ringram2077/picprojects.html

Bottom Line:  If you open a camera, then the warranty is void.  If you feel comfortable taking apart a digital camera and you know where to solder a switch to trigger the shutter, then the Michele Schiepatti Switch is a simple and inexpensive solution from Italy at: Schiepatti Switch.  If you want a turn-key solution, Aiptek camera with switch "ready-to-go", then order directly from "Wild Moose" in the USA at: Wild Moose Aiptek Pencam

SMT Soldering Technique:  Before you try soldering anything, you might want to review this link by BD Micro:   BD Micro
Equally, you could download this PDF file by Luke Enriquez to review the basics.   Hints and Tips for using Surface Mount Technology (SMT)
 
The new digital cameras, coupled with the ultralight airborne receivers used in park flyers, would seem to offer a great opportunity for aerial photography from the smaller RC blimps.  The limited weight lifting capability of these blimps would be overcome. The blimps offer an extremely stable platform for aerial photography.
 

If you think these inexpensive cameras produce an unusuable image, think again.

A pilot named GunnisonFlyer, who flies in the Gunnison, Colorado area, has submitted this image to the news group.  Keep in mind that this photo has been reduced in resolution to keep within the posting size restrictions.
 

Watch developments as they are reported on RC Groups Aerial Photography forum at:

http://www.rcgroups.com/forums/forumdisplay.php?s=55e52748a3325cec9b23fc9cde37f59c&forumid=128

The Slow Stick-Mustek GSmart Mini 3 shown below offers a unique ability to fly from a postage stamp and take excellent aerials of a neighbourhood.   The ten foot wide path was more than adequate to get the 24 ounce rig aloft.  David got this shot of a suburb in Scarborough in early April, 2003.  The year winter refused to quit.  The landing roll out was about 36 inches.
 
 

On a typical mission, the camera can take 30 digital shots with a resolution of 1600 by 1200 pixels or 20 shots at 2048 by 1536. Usually this creates an image that is far too large for web use and typically the photo is resized to 640 by 480 ppi.

The “Eye in the Sky” cost about $Cdn 500 to put together. The aircraft is quite inexpensive, but the camera and the radio control equipment make up the bulk of the cost. The plane can stay airborne for about 8 minutes. There is an Electronic Speed Controller (ESC) on board that regulates the thrust of the electric motor, under pilot control. Once the airborne battery discharges to a certain point, the ESC cuts off power to the motor to ensure that there is enough electricity remaining to power the receiver and the aircraft controls to enable the pilot to land safely.

To fly another photo mission, the camera images must be downloaded into a computer while the airplane battery can be recharged in about 45 minutes. Thus, it is feasible to fly one photo mission per hour. The real limitations are wind and sun.

The pilot has no real way to tell the exact image framed in the camera viewfinder. With practice, the pilot learns how to set up a shot. Out of a batch of 30 digital photos, only a handful will be useful. The frame might be tilted, the target not captured or the exposure not quite right – that just makes it so much more exciting when a truly great shot is captured.

Ideal photos can be obtained on a calm day with bright sunlight. The camera does not work well shooting into the sun so the pilot is challenged to manoeuvre the plane into a good shooting position. To compensate for wind direction and sun angles, the camera can be set up to shoot left, right or to the rear. Each mission calls up a different set of parameters. But, the number one variable is always LUCK.

My LUCKY shots are compiled in this web site at:   Eye in the Sky
 
 
As of June, 2003, the Soarstar on Floats carrying the Mustek Mini 3 was added.  It has the added advantage of being able to shoot straight ahead.

The floats are 19 inches long and add a total of 100 grams, hardware and all for an all-up-weight of 825 grams with the Mustek camera. 

The rig is hand-launched, photos taken and then landed on the water and taxied to the beach.  The Soarstar lands on a grass lawn with the floats as well, if not better than wheels.  This is a fairly safe rig over water. Each of the major components will float even if the aircraft breaks up on severe impact. 

For the ESC and the Receiver,  the cut off fingers of a surgical glove were used with tie wraps at both ends. For the camera,  the palm of the glove was used. A small round hole in the palm, about half the diameter of the lens, was cut and the lens poked into the hole for a friction fit. Then both ends of the palm were tied off with tie wraps. 

The Soarstar on water needs a rudimentary water rudder to permit on-water taxiing downwind.  Without a rudder, the plane will simply weathervane into wind on all but the calmest day and it will be next to impossible to get the plane back to the shore if the wind is blowing in the "wrong" direction.

The rudder shown friction fits into the steering column below the fuselage.  Assembly made from scraps.

Late Breaking News


Mustek has started to produce a new series of cameras that are CCD-based instead of the cheaper CMOS cameras such as the GSmart Mini 3.  The CCD cameras are bigger and weigh more than the CMOS versions, but the CCD technology should overcome the "jaggy" problem.  In addition, SD/MMC® external storage permits more in-the-field flexibility for more photos and multiple flights.

Mustek specifications can be seen at:

http://www.mustek.com/html/CBD.html

Mr. RC-Cam has "hacked" one MDC 3500 camera.  This camera costs less than $US 200.

Unfortunately, Mustek will not ship outside the USA.

As of June, 2003, Mr. RC-CAM has hacked the Sony DSC U20.  This camera weighs about 4.5 ounces, is a 2 meg camera that will support a 128 meg memory stick and is a true CCD imager versus the cheaper CMOS cameras.  The cost is $US200 from the Sony USA web site. 

The auto focus feature proved useless for aerial photography, but it can be set to manual focus - infinity.

Unfortunately, it is a very difficult hack as outlined in:

http://www.rc-cam.com/cammsny.htm

Casio has introduced the Casio Exilim EX-S2 and S3 models.  They are 2 and 3 meg versions, CCD and are very small.   This camera weighs 4oz with the lithium battery and 128 meg SD card installed.  The cost is in the $US 290/340 range.

This camera has a fixed focus, which might make for a simple hack using the Schiepatti Switch.

 

"Extremeone" and "Mr. RC-CAM" have identified the solder pads for a simple shutter switch trigger for the Casio Exilim EX S3.  Within the red rectangle marked, the blue scribe mark is the ground while the solder pad to its right is the shutter trigger. 

Be aware that this calls up some tricky SMT soldering.  If you don't know what SMT means, that's a fair hint that you might not want ruin a nice camera. [Use a servo instead]

[Photo by Extremeone]

35mm from Glow-powered Aircraft

For the average pilot in the glow-powered crowd, the interest is casual.  A relatively inexpensive route is to take a point and shoot 35 mm camera.  The least expensive versions are fixed focus and single frame-at-a-time.

If you have a bit more money, you will find that auto wind is a great feature that allows you to take more than one photo per sortie.  It is so hard to aim the camera that the "secret" is to take a lot of shots and to only show your friends the ones that worked out.

Full-fledged 35 mm cameras offer sharper focus and help eliminate vibration induced blurring by allowing us to take advantage of faster films to set higher shutter speeds.  Of course, we always have to keep in mind the trade-off between shutter speeds, film rating and enlargement grain.  Depth of field is not usually a consideration unless you like to fly very close to your target!

Before you try to take photos, you have to get used to the idea that you might crash and wipe out the plane and the camera.  If you can't get past that thought, quit!

There are two basic ways to mount the camera, looking straight down and looking horizontally slightly down from the horizon, the oblique shot.  Most of us are used to looking out of the window of an aircraft cabin in the oblique view.  Vertical shots are very hard to line up with a model airplane; usually, we will have much more success taking oblique shots.

That having been said, vertical shots are by the easiest way to get into business.   Simply build a small balsa box to contain your camera (shock mounted in latex foam) and use rubber bands to hold the apparatus to the side or bottom of the fuselage.  The shutter has to be tripped under your control.  The simplest way to do it is to attach a small servo to the camera with silicone bathtub sealant in just the right position so that the servo arm will trigger the shutter when an used channel, such as the gear selector, is triggered.  The silicone sealant adheres well, but has a bit of give so that the shutter servo does not stall in the maximum down position.  Two methods are shown below.
 

On the left, the clever use of a ball bearing within a race is demonstrated.  The inner race is glued to the servo arm.  As the servo arm moves, the outer race provides friction-free action.

On the right, the rubber tube compresses as it passes over the camera shutter button.

Keep the weight on the centre of gravity so that flying characteristics are not upset.  You will not notice any appreciable difference from the off-centre weight of a side mount or the increase in drag bottom or side.  This jury rig will work even for a 40 size trainer - case in point, a Skyward 40 with an OS 40 engine.  The problem with verticals is that you have to guess when the airplane is flying straight and level over your target.  If the aircraft tilts in any axis, you get a shot of the next county!  Here endeth the lesson on verticals - all that follows is about oblique shots.

The biggest technical problem is engine vibration.  Some folks have built electric powered heavy lifters that completely eliminate this situation.  They fly the aircraft to height, chop the juice, glide to the correct position and click the shutter.  Then they power up again and go around for another pass.  Unfortunately, the glow engines will give only one chance under this scenario.  Vibration can be minimized by combining three techniques:

First, rubber mount the engine, second pack the camera into the airframe with lots of good quality latex foam and lastly, keep selecting different power settings until you find a sweet spot. You can get some idea of the best engine setting by holding a finger on the airframe while a buddy moves the throttle up and down.  The best position will be different for all planes as it is a combination of the harmonics of engine vibration and airframe construction.

There is a tendency to want to protect the camera lens by having the lens look through some sort of "window''.  The best results are obtained by just letting it all hang out in the breeze with no obstruction.  But, it is best to have the opening on the opposite side to the exhaust - spent fuel plays havoc with cameras.
 
The easiest way to line up an oblique shot is to have the camera look down the wing at a down slant of about 10 degrees from the horizon.  Fly the plane so that it crosses directly in front of the pilot and press the camera shutter switch just as the wing aligns with the pilot.

In the photo shown, there is a large hole in the left side of the fuselage within which the 35 mm camera is mounted looking down the left wing.  Not quite visible, is a clear plastic water shield mounted vertically along the forward edge of the cavity - this keeps water spray out of the camera lens.

This photo also shows that a six foot Unionville Beaver, equipped with floats and powered with an inexpensive Thunder Tiger 0.46 two cycle engine has more than enough lift  to carry an Olympus Infinity 35 mm point and shoot.  There are, however, a number of tricks to learn.

The first is that you will have to take a whole roll of film to get a few reasonable shots.  In the scenario painted above, the aircraft is going to cross in front of the pilot at about 50 mph.  If you take a picture out the window of a car passing something at 50 mph, the image will probably be a little blurred.  So, the better air images are from a fair stand off distance - the blurring will be less noticeable.

Second, try to pick the sunniest days as that will let your camera use the fastest shutter speed.

Third, in your initial attempts, it might be best to enlist the aid of a buddy to trip the shutter release.  It is hard to fly a good pattern and also line up the camera.

The Beaver took this shot at the Christie Lake Fun Float Fly co-ordinated by Laddie Mikulasko.

Finally, when you shoot a roll at a Fun Fly, get a second set of prints and send them to the Event Co-ordinator.  Everybody will be curious to see if you got something and it is a nice way to say thanks for being invited to the event.