Tips for Working with Magnified Subjects
Creating a magnification ratio greater than 1:1 (macro) requires you to be extremely close to your subjects, and at such close range, even the slightest movement has a major effect on your point of focus and your exposure.
If you handhold your camera at a 3:1 ratio, your subject becomes quite elusive, even when it’s perfectly still. The movement that you cause is enough to make your point of focus bounce around, and this can become annoying or overwhelming.
The first step in eliminating movement is to put your camera on a tripod. This takes care of the shaking hand dilemma, but that’s not the end of your issues when dealing with extreme magnification. You have to position your point of focus.
You want to achieve as much magnification as possible, so your lens will be extended all the way out, and there’s only one distance at which you can achieve focus. In this situation you have to move your camera rather than using the focusing ring.
If your camera’s on a tripod, moving the camera around slightly to position the focal point is not easy. That’s where the focusing rail comes in — a piece of equipment that mounts on top of your tripod and enables you to make precise movements with the camera by twisting a dial. With a focusing rail you can pinpoint your point of focus without having to move the entire tripod.
A moving subject requires you to pinpoint your focus and then take the shot immediately before the subject moves away from the focal point. On top of that, you have to use a fast enough shutter speed to freeze the motion. Increased magnification means the lens is farther from the digital sensor and light is going to fall off before it reaches the sensor.
With light falling off, your exposure times become longer. Plus, depth of field becomes very shallow with increased magnification. You therefore need small aperture settings (like f/16) to depict more of the subject in focus. Small aperture settings require longer shutter speeds to compensate for the small amounts of light coming in the lens.
If you want to photograph moving subjects with extreme magnification, shoot in an area with a great deal of available light. Seek out bright, direct sun, and avoid cloudy days, open shade, and most indoor situations. If you do find a brightly illuminated subject to photograph, be sure not to block the light with your own shadow.
In situations that don’t provide enough light to get the shot, you can use a flash to light your subject. The flash provides enough light to allow for faster exposure times and is ideal for freezing motion. The duration of the flash serves as a shutter speed within a shutter speed, so to speak.
This photograph shows the difference between a subject photographed with a 3:1 ratio using available light and flash lighting. Notice how the available light example (left) has issues with motion blur, while the flash lighting example (right) doesn’t.