Pixiq

Over thirty years ago I became intrigued with insect flight.  I had been constructing my own hi-speed flash guns when I saw a remarkable book by pioneering photographer Stephen Dalton Called ‘Borne on the Wind’ where, through a collaboration with electronics engineer Ron Perkins he had begun to produce remarkable images showing the way insects ‘rowed’ their way through the air. These have been followed with incredible shots of animals of all sorts.

Today, with an off-the shelf DSLR you can get some pretty impressive insect shots and if you invest in something like the Phototrap™  (reviewed in my next post) the only limits are your ingenuity.

The No-Frills Approach

In the early summer heat here in Italy, Hummingbird Hawkmoths (Macroglossum stellaturum) tirelessly work the flowers of lavender bushes and, later in the year,  the Buddleja bushes.

I have real affection for these beautiful little insects and their mastery of flight since, years ago, when based in Cyprus, I used to watch how they would visit an outdoor restaurant table to probe at the sugar incrustation left on the rim of a glass of brandy sour. I have seen them at the coast and then flying close to sunny, warm cliff faces at altitudes of 2000m and more in mountains, where they rise on thermals.

Leaving the camera unattended in the hot sun was not a good idea so I did not set up the phototrap. Instead, I  used the Auto FP facility with a SB900 nikon flash - one of those amazing features not trumpeted loudly.  With Auto FP (FP = Focal Plane) mode on a Nikon D300 and other cameras you can use a flash synch speed of 1/320^th and higher (up to 1/8000^th sec) with guns such as the SB 900, 800, 600 and the SB200 macro flash.

It worked like this... first set the camera on manual exposure: do this to get the background illumination right and integrate flash and ambient light seamlessly. The background beneath the Buddleja bush was in shade so the flash provided the illumination. Camera plus flash was set on a tripod so I could tilt it to alter field of view and focus manually – the Nikon 105mm f/2.8 VR macro is fast to focus  with AF but still hunts slightly.

The trick is to wait aiming at a suitable flower and watch what comes along. The hit rate was very good circa 50%. The technique is easy and effective and can be modified to suit. It is surprising how many overlook this hidden high-speed synch capability tucked away in the camera menu…I did.

What goes on inside...

As many will know, with a focal plane (FP) shutter the synch speed is limited because the flash has to fire when both shutter curtains are wide open. It is a mechanical nightmare and the reason that shutter synch speeds are usually around 1/250^th at their fastest. If you try to use a higher speed you just get a strip illuminated as the curtains chase one another. The copal-type shutter used in rangefinder cameras (and Zeiss lenses for the Hasselblad) gives a much faster synch speed.

Nikon engineers have effectively ‘lengthened’ the flash pulse so that the subject is then illuminated for the full time that the shutter curtains are travelling across the sensor. It is not a single long flash but a series of extremely rapid, sequential pulses. To achieve this the flash output power is reduced: Nikon do not just stop at a minimum synch speed of 1/320^th (the default when Auto FP is set) sec you can work up to 1/8000^th sec…

With Auto FP the Nikon metering system takes care of ambient light, too when the “TTL. BL” (balanced TTL) option is used. It is ingenious, to say the least and a feature not trumpeted loudly.

For anyone with a Nikon system who wants to read more there is a very useful article here by Russ MacDonald

A more adventurous approach: Triggered Flash and insects in flight

I have long used auto flash guns on manual and adjust the power ratio control to get some very fast flash times. With fractional power the flash duration is shortened (and power reduced) by diverting some of the electrical energy provided by the capacitor into a ‘quench’ tube. 

For info, here is a table that gives the pulse durations at reduced power for a Nikon SB900 – data for other guns times will be similar since the trigger/quench circuitry used will not differ much – just component values in terms of capacitor size and so on.

I used this technique to get the shots of large sphinx moths - Convolvulus Hawks (Agrius convolvuli) - in flight in low light when the flash took care of all exposure and there was no need to worry about ambient light.

I discovered a form of photography that suited me down to the ground. It involved setting up Nikon D300 camera plus SB900 flash and an Infrared trigger device called a Phototrap™ ...then settling down with a large glass of red wine and waiting in the encroaching twilight (the really testing part). I’ll post a separate review of this phototrap in a day or so – it is worth it.

A slight ‘dipping’ movement of  the tobacco flowers (Nicotiana) heralds the arrival of the visitors at dusk for their rapid wing movement generates a breeze that make the flowers wobble. It increases your sense of anticipation....if the small child within is still there.

The task - to capture a convolvulus hawkmoth in flight involved ‘thinking’ like a moth … where would I put my proboscis if I wanted nectar...as it were. It was not difficult to work out where to place the camera, the trigger and wait for the action. Getting pin-point sharpness was a bit more tricky and needed persistence.

The very first picture showed just part of the moth against the background of a dry stone wall, the second captured it, revealing a proboscis that must have been some 12 cm long. For two weeks this became the nightly routine and I got to recognize the three individual moths that came. No, I did not give them names!

This is a return to something that I experimented with three decades ago when, as a one-time physicist, I built my own flashguns and, indeed, a flash meter (not a thing of compact beauty). They were hardly portable, fired on 3,000 V and exploded like a rifle going off ...leaving the distinct smell of ozone in the air – lethal, you betcha, don’t try this at home kids. How much easier it is now with the Nikon SB 900 set on manual at 1/16^th power, a flash duration of about /10,000^th sec with sufficient light to give exposure at f/22 and /250^th sec. What  pampered folk we are.

I shall post a detailed, updated review of the Phototrap in a day or so

INSPIRATION – INSPIRATION - INSPIRATION

“Out there” on the internet there are some amazing pics where people are really pushing the boundaries.

• Already mentioned is the master, Stephen Dalton I have always loved his work and dedication.
• Matt Cole has some lovely insect shots with several flight images on his site
• For those who love the gadgetry check out a retired Belgian engineer who calls himself Foto Opa (Photo-grandad). There is a stream with great detail on the development of his own system and some lovely photos.
• A real treat for anyone who wants to see what can be done the work of - Kim Taylor: here a UK national newspaper has picked up his amazing bat imagery. But to see the variety of his work in its full artistry than check out the Warren Photographic website.