Shooting distance

If you are new to butterfly photography it is tempting to fit your camera with a telephoto or zoom lens, and to take your pictures from a distance. The problem with this approach is that it's difficult to hold the camera steady, so you need to use a fast shutter speed. This necessitates using a high ISO setting, which can result in high levels of "noise" - distracting multi-coloured specks that show up in shadowy areas if you make large prints.

There are of course occasions when you have no choice but to shoot from a distance, e.g. when a butterfly is high up in a tree, so it makes sense to carry a long lens in your camera bag, but for 90% of the time you are better off using a shorter lens, ideally a 70mm or 100mm macro.

A camera equipped with such a lens will be more manoeuvrable and lighter. It will also have a wider maximum aperture, resulting in a brighter viewfinder. OK, you have to shoot from a closer distance - and it takes experience to get near to the butterfly without scaring it off, but if you wear dark clothes, approach carefully, and avoid casting your shadow on the butterfly, you'll be fine.

Shutter speeds and apertures

The easy option is to set Program mode, and let the camera take care of everything, but if you do so you need to set the ISO to 200 or 400 to ensure that the camera chooses a shutter speed of 1/250 sec or shorter duration ( to "freeze" movement ), in combination with an aperture of F11 or smaller ( to keep more of the subject in focus ). The actual shutter speed and aperture chosen by the camera will of course depend on the lighting conditions.

I like to have more control. When shooting images for the website, I set the camera to 200 or 400 ISO, and Shutter Priority mode, usually with the shutter speed set to 1/250 sec. The camera then sets an appropriate aperture for the lighting conditions - typically between F8 - F16.

There is a tendency for butterfly photographers to use very small apertures such as F22 or F32 to obtain the greatest possible depth of field. While this is fine in theory, in practice it tends to result in photographs that have an overall softness. This is caused by diffraction and the laws of physics dictate that it affects all lenses regardless of brand or price. All lenses, including macro lenses are optimised to produce the sharpest results in the F5.6 to F11 range, and stopping down beyond F16 is definitely not recommended.

Metering and bracketing

Advertising hype will tell you that digital cameras have sophisticated light metering systems that compare the scene in the viewfinder with an on-board database representing 1000's of different scenes. Using advanced algorithms they calculate the exposure needed, and set a suitable shutter speed / aperture combination. Thus with "average" subjects it is unusual for a DSLR to deliver an inaccurate exposure.

Butterflies however are far from being average subjects - they range from very dark, almost black Ringlets, to dazzlingly reflective Whites and Morphos. Furthermore butterflies often settle on bare ground or other reflective substrates that fool metering systems into under-exposing, resulting in a very dark image. You can have similar problems when photographing brightly coloured butterflies against a very dark background such as shown in the photos below.

OK, you can use the exposure compensation control on the camera to correct this, but while you are figuring out how much compensation to dial in, and fiddling with the camera controls, it's very likely that the butterfly will have lost patience and flown away !

The answer is to "bracket" your exposures. This simply means that you shoot a rapid series of images, typically a series of 3 shots, with the first shot "as suggested" by the camera, followed by additional shots taken at different settings. This provides you with a series of images ranging from bright to dark. I would strongly recommend that you forget about using exposure compensation, and standardise on shooting a bracketed series of images on every occasion. All modern DSLRs have an option to shoot a bracketed series automatically.

Using flash

Funnily enough, when the sun is shining brightly, I usually use flash !  This may seem odd, but in sunny conditions butterflies are often very active, and the short duration of the flash ( typically about 1/2000 sec ) is better at "freezing" their movement.

Although the flash duration is short, the light output is very high - brighter than sunlight at close distances. This means that apertures as small as F32 can be used, resulting in greater depth of field, although as previously stated, going smaller than F16 is not recommended.

Another advantage of flash is that it can be used to lower the contrast ratio of the image by putting light into the shadow areas - a technique known as "fill-in flash".

Dedicated flashguns

"Dedicated" flashes automatically set the correct shutter speed for correct flash synchronisation, typically 1/125 or 1/250 second. They also transmit a "correct exposure achieved" signal to the viewfinder, and usually incorporate a timer which turns the flash off after a few minutes to save battery power, and turns it on again when you put half-pressure on the shutter release.

Dedicated flash units are produced by Canon, Nikon, Olympus, Pentax and Sony for their respective cameras. Aftermarket manufacturers including Sigma, Sunpak and Braun also produce flashguns dedicated to certain cameras. All of these manufacturers also produce special extension leads to enable the flash units to be used off-camera.

Auto flash

Modern DSLR cameras meter the flash intensity either directly from the image plane, or from the focussing screen. In a split second the camera measures the strength of the flash light coming through the lens, calculates the variables such as aperture, subject distance, ISO setting etc, and controls the duration of the flash burst to achieve correct exposure.

Some systems work better than others, and it is often necessary to use exposure compensation if the subject is very pale, very dark, or if the background is some distance behind the subject.

Pre-flash

DSLRs usually fire a low power "pre-flash" a fraction of a second before the main flash. This pre-flash is used to meter and set the flash burst duration of the main flash.

Unfortunately for us, many butterflies have extremely sensitive eyes and incredibly fast reflexes, so when the pre-flash fires, the butterfly instantly flicks it's wings, or flies off, leaving the photographer with a blurred image, or nothing at all !

For these sensitive species alternative methods must be used :

One option is to set the flashgun to fire manually on full power ( or fractional settings if available ), in which case the camera does not trigger a pre-flash. In these cases the flash burst duration is fixed, and the aperture must be adjusted to achieve correct exposure. The appropriate aperture will be dependent on subject distance, flash output and ambient lighting conditions, so it is necessary to take a few test shots beforehand, and use the results as a guide to which settings to use in the field.

The other option of course is to shoot these species by natural light.

Off-camera flash

Flash often produces unnatural results - butterflies can look like cardboard cut-outs, and reflections from the flash can make the wings look too shiny, particularly on older worn specimens that have lost a few wing scales.

You can minimise the problem by using a flash mounted on a bracket at 45 degrees above and to the side of the camera. This provides a more 3-dimensional lighting and eliminates the reflections, but tends to produce excessively dark shadows. You can improve the results by using the integral flash as a supplementary light to "fill-in" the shadows.

Ring flash

A ring flash normally consists of a single circular flash tube which surrounds the lens. Some models have a different design, with either 2 or 4 tiny flash tubes built in to a housing that screws into the filter mount of the lens.

Both types produce soft and virtually shadow-less illumination similar to that produced by daylight on an overcast day. Their devotees extol the virtues of soft lighting and ease of use, but the textures of the wing veins, scales and the foliage on which the butterfly is resting all tend to get lost, leaving a dull lifeless image. You may be able to use a ring-flash in combination with an off-camera flash, but things then start to get very cumbersome !

Ring-flashes are marketed by Canon, Nikon, Sony, Pentax, Olympus, Sigma and various other brands, and are dedicated to particular cameras.

Twin-macro flash

Twin-macro flashes consist of a pair of small flash heads, mounted on a ring surrounding the lens. The flash heads are linked by cable to a "controller" which sits in the camera's hot-shoe. The controller lets the user choose between using auto-flash, or manual output, and in most cases will allow each flash head to be set individually to fractional power settings.

Normal practice is to have one flash operating at full power to provide modelling and texture, and the other at half power to fill-in the shadow areas. The effect is usually very pleasing. The flash heads can be set to a number of positions around the ring, and can be angled to point the light directly at any subject regardless of distance.

Most twin-macro flashes come as a complete kit, with diffusers, wide-panels, extension arms and adaptors to fit various lenses. Canon, Nikon and Sony market models dedicated to their respective cameras, Currently there are no independent models available.

Diffusers