The following basic principles apply when photographing insects, they are:
1. Make eye contact
An insect image will have far greater impact if taken at eye level. Most insect images taken from above typically lack impact (although they may be useful for ID purposes)
2. Maximise depth of field
When the subject matter is highly magnified, as it often is when photographing insects, the depth of field becomes extremely shallow. In order to get as much of the insect as possible in focus it is therefore necessary to use as small an aperture as possible. If this still does not result in the entire insect being in focus then the usual trick is to focus on the insect's eye. However, one way of helping to ensure that the whole insect is in focus is to photograph the insect side-on, so that the insect is parallel to the front of the lens. This is particulartly effective for butterflies with their wings closed and for long insects such as damselflies and dragonflies.
3. Pay close attention to the background
Insect images typically look best if the insect is isolated against a clean background. It is therefore important to (a) try to get your subject as far away from background foliage as possible and (b) to use just enough depth of field to ensure the insect is in focus but no more than that or else the background is more cluttered than it needs to be.
4. If using natural light, don't shoot in full sun
Not a great deal more needs to be said on this point. Full sun will tend to result in harsh highlights and deep shadows and generally provides less attractive macro images. Better results will be achieved shooting in cloudy conditions since the cloud softens the light by acting in the same way as a flash diffuser. Speaking of flash...
5. Don't be afraid to use flash
Some photographers prefer to use only natural light for macro work on the basis that the use of flash can make the image look artificial. Although this can be true if too much flash is used or if it isn't diffused well, flash does have a number of benefits. Firstly, it allows a smaller aperture to be used and hence provides greater depth of field ; secondly it picks out detail and hence can provide sharper-looking images; thirdly, given some insects' preference for lurking in the undergrowth, it provides photographic opportunities which simply wouldn't have existed if flash were not being used; finally, if lighting an image entirely by flash, the very short duration of the flash acts in the same way as a very fast shutter speed and can remove motion blur.
6. Try using a mix of flash and natural light
When lighting an image entirely with flash you will always get a black background unless you are very careful to ensure there is some foliage or petals in the background very close to the subject. Sometimes, however, it can be desirable to illuminate the subject matter using a diffused flashgun (in order to gain from greater depth of field and to freeze movement) but to allow natural light into the background. In some ways this technique provides 'the best of both worlds.' When shooting in this manner I will normally use aperture priority and will dial in -11/3 (one and one third) or even -1 2/3 (one and two thirds) negative flash exposure compensation to ensure the flash isn't too strong.
7. Capture interesting behaviour or action
Images are often more interesting if they contain some natural behaviour or action rather rather than merely a static insect.
8. Capture the insect's environment
Most of the above shots show the insect in isolation from its surroundings. Sometimes however, including the insect's environment can provide a more interesting image. A wide angle lens with close focussing ability, or a fisheye lens, are the best lenses for this sort of shot and it works best with fairly large insects.
9. High Magnification Macro
If your equipment allows, why not try high magnification macro? Although a lens such as the Canon MP-E 65mm is ideal for this sort of image, you don't have to break the bank to shoot high magnification images. Try reversing a basic 50mm lens (you can get adapters to fit the reversed lens to the camera) or try extension tubes on a macro lens (the smaller the focal length of the macro lens the greater the effect of the extension tubes) or try clipping a Raynox DCR-150 or DCR-250 close up lens onto a macro lens. Obviously the greater the level of magnification the shallower the depth of field, so some care is needed to ensure that the insect's eye is in focus.
