One of the most popular books that I read during my childhood was Eric in the Land of the Insects, written by the Dutch author Godfried Bomans. In this humorous fantasy, nine-year-old Eric enters the landscape painting that hangs on his wall and he discovers a world of man-sized wasps, bees, butterflies and other insects that is stunningly similar to the world of humans. Once photography became a part of my life and I purchased the Canon extreme macro lens MP-E 65 mm f/2.8, my world was populated with grasshoppers, spiders, snails, flies, dragonflies and butterflies—Eric’s world.
Magnification describes the relationship between the actual size of the subject and the size of its image on the sensor of the camera. Photographing a 3 cm (1.18 inch) long blue-tailed damselfly so that its image size is 1 cm (0.39 inch) on the sensor means that the magnification is 1/3 (1:3) life-size. Dividing the size of the subject’s image on the sensor by the actual size determines the magnification. At 1:1 life-size, the size of the subject on the sensor is as big as it is in real life. Macrophotography is restricted to magnifications in the order of 1:10 to 1:1 life-size. Microphotography is the extreme form of macrophotography, dedicated to the photography of small objects from life-size to modest enlargements of up to about 20.
Portrait juvenile grasshopper: Magnification 6, f/11, ISO 100 and 1/250 sec.
Approaching Insects
Although most insects do not have orifices in their body for picking up sound vibrations, many use parts of their body, such as their wings, antennae, or special hairs, like TV antennae to detect vibrations in the environment or in the air. Any errant movement on your part could cause you to lose a shot, so be sure to tread carefully when approaching your subjects. Your job is to make yourself non-threatening. The first thing you want to do is to move very slowly. Look before you move, look at where you place your feet, look at where your equipment is, and most of all plan where you are going to put the front of your lens. Many potentially good shots have been ruined by the front of a lens bumping a branch or leaf where an insect was resting, causing it to flee.
Insects such as the housefly, the hornet, the butterfly, and the beetle, have what we call compound eyes. These eyes are made up of many separate units called ommatidia. Each ommatidium samples a small part of the visual field. Having multiple ommatidia allows the animal to easily detect motion. Some, like the dragonfly, have as many as thirty thousand units per eye, each with its own lens. With a compound eye the insect sees a mosaic image. This looks something like the highly magnified dots of a newspaper photograph. Because the lenses in the insect’s eyes have a fixed focus, and can’t be adjusted for distance, insects see shapes poorly.
As an object moves across the visual field, ommatidia are progressively turned on and off. Because of the resulting “flicker effect”, insects respond far better to moving objects than stationary ones. Honeybees, for example, will visit wind-blown flowers more readily than still ones. Houseflies and dragonflies have eyes that cover most of their head. This gives them almost 360 degree vision, enabling them to see predators coming from any direction. Most insects can see some color. While our eyes see a full spectrum of wave lengths from red to violet, many insects see a limited range of colors. The colors they detect are the ones most useful for finding food and shelter.
It is known that insects, especially flying insects, will try to escape from a predator by a simple escape reflex based on the direction and the velocity of a moving shadow or object. If a critical velocity is exceeded, the insect will try to fly away from the direction of the threat. Slow moving objects or shadows often do not trigger this reflex. The lesson learned is that the best way to approach an insect is to move slowly and gently. Most of all, avoid casting your shadow on the insect.
Two female jumping spiders (second one has caught the first one): Magnification 4, f/14, ISO 100 and 1/250 sec.
Larger than Life-size
Strictly speaking, a lens is categorized as a macro lens only if it can achieve this 1:1 magnification. Microphotography can be undertaken by normal macro lenses equipped with modestly specialized equipment. A lens’ minimum focusing distance is the closest distance your macro lens will allow you to get to your subject while still maintaining sharp focus. A low-budget method to decrease the minimum focusing distance is to extend the distance between the lens and the sensor by inserting extension tubes or a continuously adjustable bellows. Both the extension tubes and the bellows do not contain optical elements. The further the lens is from the sensor, the closer the minimum focusing distance, the greater the magnification, and the darker the image given the same aperture. Tubes of various lengths can be stacked, decreasing lens-to-subject distance and increasing magnification. Extension tubes and bellows can be used for different lenses. A small disadvantage is that the use of extension tubes and bellows may not preserve autofocusing, auto exposure and auto aperture operation.
The maximally obtainable magnification can be calculated with the following simple equation:
(D (length of the set of extension tubes or the bellows) + F (focal length of the macro lens)) ÷ F = magnification.
For Example: Adding a set of extension tubes with a total length 0f 60 mm to a 60 mm macro lens will give maximally a magnification of (60+60) ÷ 60 = 2.
By adding a teleconverter, an even greater magnification can be achieved. Application of a 2x teleconverter produces a maximum magnification of 2 and 2 stops loss in light intensity. Adding more glass means a drop in quality and quantity of light transmission, the extent of which depends on the quality of the particular teleconverter you’re using.
Placing an auxiliary close-up lens (or close-up “filter”) in front of a macro lens is another option. Inexpensive screw-in or slip-on attachments provide close-focusing at a very low cost. Some two-element versions are qualitatively very good while many inexpensive single element lenses exhibit chromatic aberration and reduced sharpness of the resulting image. When you use macro lenses with different diameters, for each macro lens a close-up lens has to be purchased separately. Most close-up lenses are marked with a +d number in diopter unit, the power of the lens. The diopter (or power) of a lens is defined as 1000 ÷ Fd, where Fd is the focal length of the lens measured in mm. Thus, a lens with a focal length of 50mm has a diopter of +20 = 1000 ÷ 50, and a +4 diopter close-up lens has a focal length of 250mm = 1000 ÷ 4.
The maximally obtainable magnification can be calculated with the equation (2F + Fd) ÷ Fd.
For Example: coupling a +20 diopter lens with a 60 mm macro lens produces maximally a magnification of (2*60+ 50) ÷ 50 = 3.4.
An interesting alternative is the reverse lens technique which can be accomplished by mounting a lens with focal length Fr in reverse, in front of a normally mounted lens of greater focal length F, using a macro coupler which screws into the front filter threads of both lenses. The maximally obtainable magnification can be calculated with the equation F ÷ Fr. Depending on the quality of the reversed mounted lens, a drop in quality and quantity of light transmission may negatively influence the image quality. All discussed techniques can be used in conjunction to obtain even larger magnifications.
Portrait of a black garden ant with a length of around 5 mm. The color varies from brown to black: Magnification 8, f/6.4, ISO 100 and 1/250 sec.
Composition
The increase in magnification reduces the depth of field in an image, decreasing the total area of the image which is in sharp focus. This provides another disadvantage. The reduced depth of focus makes it more vital to think about composition and selecting which area to place the most focus on. Magnifying the image also magnifies any movement of the camera and the subject, so it becomes far more challenging to make super sharp images.
Even with all the limits of insect photography, photographers have found ways of going around them and producing vivid images. There is an inverse relationship between magnification and depth of focus. To make up for the limited amount of depth of focus, photographers are more careful of what areas to include in the final image. Composition is a key element to insect photography. In most cases, we want good focus and sharpness on the eye of the insect that we’re shooting. But with depth of field of less than a fraction of a millimeter, getting any part of the animal in focus can often be quite a challenge.
When deciding whether or not to include a subject’s entire body, one guideline to remember is to ‘cut hard or not at all’. It’s often problematic to include the whole subject in a frame. Apart from anything else, some insects have very long antennae, so including the whole body would mean shooting at a relatively small magnification ratio.
Capture the aspect which makes the insect unique. If it is the insect’s mandibles, then compose the image to show the insect when it is eating. For maximal sharpness throughout, adjust the angle of your camera so that the plane of sharpest focus aligns with the head/plane of your subject. Play around with composition until you get something that works.
Small wasp on dandelion, size around 1.5 mm: Magnification 8, f/8, ISO 100 and 1/250 sec.
Focusing
Working with large magnifications means that the subject is only a few centimeters in front of the lens. During the day time insects move from feeding place to feeding place or are hunting. They stop only for very short periods of time at a specific place to forage, which means that there is no time to set up a tripod. One needs to hand-hold the camera to make the photos. Magnifying the image also magnifies any movement of the camera and the subject, so it becomes far more challenging to make super sharp images.
Because I am hand-holding a relatively heavy and bulky setup, it is not possible to focus using the lens focusing ring, which also determines the magnification. Rather, I pre-set the focusing ring based on how much magnification I want. Once the focus is set, I will physically move the lens, mounted on the camera body, back and forth until the facets in the compound eye(s) of my subject are in perfect focus in the viewfinder. This is the tricky part, obviously, as a fraction of a millimeter can significantly affect the focus. For instance, at five times life-size the depth of field of the MP-E 65 mm at f/16 is 0.269 mm. For higher magnifications, the situation is even worse. In order to stabilize the whole setup, I’ll rest my elbow on my knee or both elbows on the ground. As soon as I see perfect focus being achieved, I’ll press the shutter button to take a photo.
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Detail head of speckled bush-cricket: Magnification 8, f/8, ISO 100 and 1/250 sec.
Micro lighting
By far the biggest challenge to microphotography in the field is getting enough light on the subject. Light is lost when using macro lenses, extension tubes and teleconverters. As magnification increases, depth of field decreases rapidly. Due to loss of light and depth of field considerations, it is advisable to use a ring flash or twin flash when shooting micros. It will allow you to shoot at a reasonable speed, yet enable you to use a small aperture for sufficient depth of field and a fast shutter speed (e.g. 1/200 sec) to capture moving insects. It becomes a necessity for most shooting above magnification 1:1 simply because there is normally not enough light.
Front lighting will provide better color saturation, while side lighting gives your subject more light on one side than the other. This gives the picture a greater sense of depth and dimension even though it’s a two-dimensional image. A ring flash will provide an even level of lighting so that your image won’t have strong highlights and shadows, but the downside is that this often looks unrealistic because the flat front lighting produces a flat appearance.
A twin-flash system will produce a more natural lighting situation and the results are often more appealing because there is more dimensionality to the image. Being able to choose the position of twin-flash units allows you to mix front lighting with side lighting. Twin-flash units also allow you to change the output levels of light. One flash may be brighter than the other, giving you much wider latitude for creating more natural shading and a greater sense of depth. The two flash tubes/heads can also be independently rotated around the lens rim to adjust the location of highlights and shadows, thus better matching the shooting situation and creative intentions of the photographer.
Getting the light just right is never simple. While single or twin-flash units give us the opportunity to add light, sometimes, even with controls that allow us to vary the light output, the added light is still too harsh. To soften the light, you can choose to use flash diffusers. Diffusers are translucent plastic covers placed over the flash head so the light passes through them, softening the light.
Huub de Waard
Huub de Waard is a Dutch wildlife photographer who specializes in insect macro photography. He photographs very small invertebrates so close-up that they are transformed into large subjects.
Through his images he aims to highlight the different characteristics of a variety of species – and their individual charm.
He does not apply focus stacking and all of his pictures are single images made in his own garden. His work can be found at http://www.huubdewaardmacros.com/
