Thursday, September 4, 2008

Photography tips: macro photography and lighting

Everyone who has ever tried shooting macro shots knows that close-focussing distance comes with a huge loss of depth of field. Even at fairly small apertures like f/8 or f/11 it is hard to get an entire bug in focus. Yet if we look at 'professional' macro-shots, we see crisp and clear images. How on earth do they do that?

The answer is simple: use a flash and narrow your aperture even further. Macro lenses often go up to f/32, so that's not the problem. The problem is the direction of light. On-board flashes come from the wrong direction. Your lens gets in the way and casts a shadow over your subject. So, don't use an onboard flash, use a separate one.

Ring flashes
Flash manufacters make so-called ring flashes. They are to be mounted on your lens, and provide light from the exact same angle as your lens. This implies a total lack of shadow. It also implies that light is pretty flat, which may be desirable for some types of portraits, but not for macro photography. The very expensive types have the option of balancing (even aiming) left and right lights to solve this problem, but they come at a price. Apart from that, a ringflash might simply get in the way while trying to shoot bugs.

Off-camera flashes
The other option is to use an off-camera flash. You can either hand-hold it (very flexible), hand-hold it on a monopod (for more reach and stability), put it on an extension arm mounted to the camera (follows the camera wherever you point it) or put it on a tripod (stable, and you have both hands available for the camera). I use either of these options, depending on the situation. The main disadvantage of using an off-camera flash is the shadows it casts. This is not always a problem, but if it is, it may be softened by using a fill flash or a reflector. I have a nice small ring reflector that fits on my lense. It fills just like a ringflash would, and since it is not my main light source, I do not have the problem of flat lighting.

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