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Understanding Exposure
Exposure is the amount of light that hits the film in the camera, or nowadays the sensor.
A correctly-exposed image is one of the first steps in making a pleasing photograph - an underexposed image appears too dark and details in the dark-coloured areas are lost, while an overexposed image will be too bright and details in the lighter areas are lost. Modern cameras now have in-built light meters that detect the amount of light in a scene and adjust the camera's setting accordingly. Most folks using compact cameras and those just starting out using a prosumer or SLR camera will find it easiest using Auto mode. In this mode, the camera detects the light levels in a scene, and will set all its parameters automatically to produce a correctly-exposed image.
The 3 parameters that contribute to exposure are aperture, shutter speed, and film sensitivity (or ISO). Aperture is the open window or hole which lets light in - the larger the aperture, the more light enters. The shutters are mechanical curtain just in front of the sensor, which opens and closes at a given speed ("shutter speed") - the longer these curtains are opened, the more light enters. Finally, ISO refers to the sensitivity of the film or sensor to light - at higher ISOs, the sensor will require less amounts of light to produce an image of the same exposure.
Although the camera's Auto mode does a fairly good job to setting all these 3 parameters correctly, there are situations where the camera can be fooled into giving the incorrect exposure. Also, the ability to control these parameters independently gives you the freedom to tweak various aspects of your photograph in creative ways. Happily, most prosumer cameras, high-end compacts and SLRs allow the user to access these functions.
In Aperture Priority mode, you can set the aperture value, and the camera will adjust the ISO and/or shutter speed accordingly. This is my favourite mode for taking plant photographs. Aperture values are expressed in f/ stops - where the larger the f/ number, the smaller the aperture size. (i.e. f/11 yields a smaller hole for light to pass through as compared to f/4) Therefore keep in mind that if you use a larger f/ stop, you are effectively limiting the amount of light that enters, and will therefore the camera either has to increase the ISO or use a slower shutter speed in order to gain the correct exposure.
What really makes Aperture Priority mode shine in plant photography is the fact that aperture size influences the depth of field (DOF). DOF is the portion of a picture that appears discernably sharp. If only a small portion of the picture is in focus, this is referred to as having a "shallow depth of field". The areas that are vaguely out of focus behind then forms what is termed a "bokeh". If you were thinking of showcasing a particular plant, or part of a plant, amongst others in your collection, you will achieve good results by using a shallow depth of field (which mandates the use of a large aperture) as this separates the subject from its background. On the other hand, it will make sense to utilise a deep depth of field (i.e. a small aperture value) if you want to take a landscape-like photograph of your entire CP collection.
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Using a smaller aperture, the background is blurred leading to subject isolation.
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Almost all subjects in the frame are in focus at higher aperture values.
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Shutter Priority mode allows you to set the shutter speed (expressed in seconds, or fractions of a second) while the camera adjusts the aperture to achieve the right exposure. A fast shutter speed (combined with the correct aperture and ISO values) serves to freeze action, and therefore may be called into use in situations where you are trying to take a photograph of, say, Drosera filiformis which is waving about in a breeze. By and large however, I rarely use shutter priority mode in plant photography as fortunately CPs do not attempt to flee when you try to photograph them.
Finally, SLRs and some prosumer cameras/high end compacts also offer a fully Manual Mode. In this mode, you have control over BOTH aperture size and shutter speed. This is the most flexible mode which can be called into use for creative attempts or in tricky situations. For example, you have a Drosera filiformis flapping all around in a breeze, and you want to 1) maintain a deep depth of field , and yet 2) freeze its motion so that you get a good sharp shot. To do this, you require both a small aperture (which, if you remember in aperture priority mode will require a slower shutter speed to avoid overexposure) and yet a reasonably fast shutter speed to freeze motion. In such a situation, the camera without a flash will have difficulty finding this middle ground where you have a small-enough aperture and a fast-enough shutter speed, but you can achieve this in Manual Mode. First, decide on what aperture size you want, and toggle the dials/wheels on the camera to set the f/ stop. Look into your viewfinder, where there will be a graphical representation of a light meter, ranging from perhaps -2 to +2. The zero (0) point is where the picture is correctly exposed. Start toggling the dials to adjust your shutter speed up or down until the indicator on the light meter in your viewfinder reaches the centre (zero), or as close to it as possible. If required, you may want to increase or decrease your ISO accordingly. Once the indicator is on the zero mark, the picture will be correctly exposed. Check your shutter speed to make sure that it is fast enough to freeze motion - if not, you may have to increase your ISO sensitivity to achieve a combination of fast shutter speed plus a small aperture.
Composition
Apart from the technical aspects of photography, a good CP photograph also involves good composition. Composition of a typical plant photograph isn't as crucial as, say, an artistic photograph, but still serves the important function of drawing in the viewer's eye to the correct areas. I generally follow the Rule of Thirds in most CP photography. Divide the frame into 3 rows and 3 columns using imaginary lines, and essentially the subject of interest should rest on at least one of the intersection points where these lines meet.
Another easy mistake people make is to simply tower over their plants and take a top-down shot, as what you would normally see when just passing by your garden. These pictures do not convey detail. It is best to bend, stoop, squat or (in a worse case un-glam scenario) lie flat on your tummy to take a picture of the plant in profile at eye level. This makes for a more interesting photograph, and also serves to provide an unusual viewpoint of an otherwise mundane plant. There are of course exceptions to this, such as when taking photographs of pygmy Drosera. Even then, a slightly angled view can prove to be more interesting than the usual top-down view.
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Sarracenia purpurea ssp. venosa shot from the top. It shows off the growth habit nicely, but there is no defined subject and little interest. |
The same plant, this time done from an angle. |
Sometimes you may wish to provide a size reference for your photographs so that the viewer can gauge how monstrous (or tiny) your N.attenbourghii pitcher is. However, AVOID using your hand as that size reference. This is a common technique people like to use, but 1) everyone's hands are different in size, and sometimes drastically so, plus 2) it just looks plain ugly with a disembodied forearm sticking out through the front of the photograph. For something simple and direct, you can place a ruler next to your plant. Fancier (or simply more aesthetically-pleasing) references should ideally be things that people can easily identify with, such as a dime, matchstick or even living stuff like live sphagnum moss and a bee or fly. If you really insist on being in the photograph or having a human in it, frame it such that the entire person is part of the composition, or at least include enough of the person so that it does not look like you were involved in some gruesome body-parts murder.
Other specific tips
- The time of the day is crucial in taking a good photograph. Try to take them in the soft, diffuse natural lighting conditions which are found at dawn and early evening, instead of at noon where the mid-day sun casts hard, unflattering shadows on your plants. If you really can't take the shots at any other time, you might want to consider artificial lighting and flash photography instead.
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| Sarracenia x catesbaei, photograph taken at about 1pm. The light is coming almost from the top, casting hard shadows on the pitchers. |
The same plant taken in early evening. The colour tone is a little cooler, but more importantly there are fewer hard shadows that can obscure details. |
- Lightly misting the plants before taking a photograph is an easy method of conveying the message of life and freshness. A light mist on some Drosera can also help to increase the glistening effects of the dew, especially if the lighting used is incidental from the side.
- Isolate your subject matter not only using depth of field, but also by considering the background colour and texture. This is easy if you're shooting under controlled lighting indoors as an artificial background can be used. In the typical outdoors collection shot, try to move the plant or at least frame it against a simple, non-distracting background.
- Experiment with different and novel points of view. The most striking pictures of Darlingtonia were not taken of the entire pitcher from the side, but rather from uncommonly-explored angles such as through the mouth of the trap or from a top-down view.
- It is not always necessary to include the entire plant. Sometimes, taking a photograph of a specific part creates more visual impact. However, make sure that there are enough distinguishing characteristics in that specific area so that its context can be known easily.
- "Action shots" of your plants with captured prey are some of the most distinguishing points in CP photography, and always make for interesting pictures. In these shots, make sure the focus is defined clearly, such as on the insect's eyes.
- In areas of poor lighting, or while doing macro photography, use a tripod to prevent camera shake.
- When photographing wild plants, DO NOT DIG THEM UP TO GET A BETTER PICTURE. Leave the plants alone, and go down low as stated above. A little shifting of the surrounding non-subject foliage or leaf litter is acceptable, just do not harm its habitat.
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Photography Basics
