Photographing Insects in Flight

We have been developing kits to photograph insects in flight since about 1975, back
in the days of film cameras and complicated home-built flash units to get the requisite
short duration multiple flashes at the power required for 64 ISO speed film.

Below is a photograph of the current state of our art. A cover fits over it for storage or
transport. For scale, the base (almost the width of the first image) is 1.13 metres long.

The black rectangular item just right of centre is the normal trigger beam with
a pair of IR LEDs (Infra-red Light Emitting Diodes) and sensor at the tip.
We can slide the box across the 'stage' to allow for the insect's speed of flight.
The operator sits behind the sliding box and tries to tease insects with soft paint brushes
to fly in the wanted direction. A bright window in the wanted flight direction is a big help
except for some species of moth.

Inside the white box is a another beam break (5 IR LED/sensor pairs) occasionally
used for different views. This used to be our primary flight direction (towards
the camera at the right) but we get more flights and better images with the
insects flying across the 'stage'. The setup is large enough to include
the whole of the UK largest Dragonflies with a bit of margin.

The camera is on a mini sliding mount looking left into the dark box but
focus locked onto the centre-line marked in white just below the centre of the
first image.

There are 3 flashguns all electrically (not radio or 'slaved') connected to the

  1. The obvious gun on the right providing the main light. 
  2. Under the camera is a 'fill' flash tucked under the camera on its side with
    a wide angle diffuser
  3. Finally a 'background' flash inside the big white box used to illuminate a
    painted sky.

All of the guns run at very reduced power, typically 1/32 (3% of maximum power) in
order to get a very short flash to freeze the wing motion. Details later.

The camera is set at X-sync speed, F29 (very small for maximum depth of focus)
fast multi-frame and mirror locked up. The control electronics 'holds down the shutter'
for the time required for the camera to take 3 frames (or however many you want
and the flashguns can manage)

Bottom left is the control electronics:-
  A small PC of great vintage with parallel printer port used as control signals. It runs
  MSDOS from Windows 95 but with the right fudges for port access and a PCMCIA
  parallel port card you could use anything. If we built the kit again now we would use
  a 'Raspberry Pi' and write the software in Python.

  A large steel case containing sense amplifiers for the beam break, and power supplies.
  This content of this box is about 20 years old & can't be re-built the same.

Ref: P34_20090503_1523_917 Flight tunnel setup (ft1)(r+mb Sample@768).jpg 146K

P34_20090503_1523_917 Flight tunnel setup (ft1)(r+mb

Inside the large white box - the painted background, replaced with black velvet and the
flash turned off for night flying moths and multi-flash.

Ref: P34_20090503_1524_927 Flight tunnel setup (ft1)(r+mb Sample@768).jpg 108K

P34_20090503_1524_927 Flight tunnel setup (ft1)(r+mb

A clearer view of the camera and flashes 1 & 2.
Flash 2 being on its side is fine because it is set to very wide angle.

Ref: P34_20090503_1524_933 Flight tunnel setup (ft1)(r+mb Sample@768).jpg 126K

P34_20090503_1524_933 Flight tunnel setup (ft1)(r+mb

Another view of the kit configured for strobe effects. Flashgun 1 is moved so as
not to illuminate the black velvet background, and is the only flashgun used for this.
The exposure varies. 

Ref: P34_20100917_1125_436 Flight Tunnel 1 multiflash strobe configuration (orig)(r+mb Sample@768).jpg 148K

P34_20100917_1125_436 Flight Tunnel 1 multiflash strobe
        configuration (orig)(r+mb Sample@768).jpg

The electronics has been moved from system to system and is very old.
The sense amplifier looks for sudden reductions in brightness rather than
absolute levels so adjusts well for ambient light. This is the decades old

Ref: Flight Tunnel 1 (FT1) Beam Sensor (web size).gif

flight tunnel 1 (ft1) beam sensor (web size).gif

The setup is complex, and its a year between main sessions, so we work from a check-list
that includes lots of setup details. The easiest way of presenting this information seems to
be simply include the list with irrelevant stuff removed:-


Boot Toshiba Micro-PC into DOS (F8 at start of boot)
  and start FLIGHTUN (else shutter is left pressed) &
     CD  \FLIGHTUN<enter>
  (or continue from previous hibernation).
Flash cables into Camera Hot shoe.
Check Hot Shoe battery OK Light.
Select Flash power 'SE' for required guns

Load in Camera preset file:-
    Settings include 1/250 sec, F29, Manual, Fast Multi-frame,
    MIRROR LOCK mode 2 (mirror STAYs up after each shot)
    30 minutes to power off, 160 ISO
    No aperture board, Normal angled sky board.

STROBE flash:    
     Fit 16cm aperture board (stops flash lighting background).
     Camera changes from standard:-
         Single frame, ISO 250, Shutter speed to match MULTI.
     Fill and background Flash: OFF
     Main Flash: Move to Forward position
         MULTI --- off, 1/32,
         50Hz: Set shutter to 0"3     (300mS = 16 frames)
      or 80Hz: Set shutter to 1/5 Sec (200mS = 20 frames)

FLASH: Position    Gun  Angle  Power  Zoom

       Main (Left)  5    90     1/32   50   (OFF FOR STROBE)
           Normal: Mounted in raised rear position
           MULTI:  Mounted in low forward position extreme left.

       Fill (Horizontal mounted sideways under camera lens,
             18mm = diffuser pulled out and over flash aperture)
                    3    90     1/64   18   x times y Hz as Requ.

       Background   2    Dip    1/32   28   (OFF FOR STROBE)

Select Stage aperture size & Fit Canon 28-135 mm ZOOM.
Normally used at 105mm near closest focus.
Software shutter press time is 450mS to give 3 frames per press.

Test barrier & trigger selection.
Shutter release switch cable connected.

Up the Tunnel:      Frame and Focus in front of barrier.
Across the Tunnel:  Frame & Focus on Cross flight line.

Lens to Manual Focus (if used to set auto-set focus).
Lens to Stabilizer OFF (if present)

Expose test card using a beam break - check required guns flash.

REGULARLY:            Check flash 'ready' lights
WHILE DISMANTLING:    All flashguns to OFF

Example images

Ref: 20090516_dc1_20090423_1345_185+1357_199 ft1 orange-tip butterfly male flying over red campion (montage)(r+mb id@576).jpg

Only the orange tip butterfly male (shown here) sports the orange tip that gives the
species it's name. The female does share the delicate green tracery with her mate.
The insect and plants are often photographed separately with exactly the same
setup (and choosing a suitable plant for the insect) and then montaged together
as indicated in the filename.

Ref: 20101108_da1_20100917_1234_018_ft1 common darter dragonfly male in flight strobe @ 80hz (crop)(r+mb id@768).jpg

This image is taken as a single exposure using a strobe light - a very fast flash with the shutter held open.
80Hz means 80 flashes a second, so the image below last for about 1/10th second. These have to be photographed
against an extremely black background (typically 20 flashes hit it) and are not photo montages but made
'in the camera' with the images appearing to be transparent.

Last Updated: 20 Jan 2013.