How to Shoot a Macro Shot with Proper Exposure
Exposing a macro shot is not as simple as trusting your meter and taking the photo. There are several factors to consider before clicking the shutter release.
Step 1: Business as Usual
The most difficult part of macro photography is dealing with depth of field. Once you have come to the realization that you need to close down your aperture in order to get more depth of field, you may find yourself set to an F22. To compensate, you have added a good deal of light to your scene and set your shutter speed to a 1/125. This way, you will not have any motion blur or ambient light problems. However, you may not be ready to shoot yet.
Step 2: Aperture Corrections
It is now important to understand that the actual size of the hole that an F22 creates is extremely small. This pinhole aperture can cause diffraction in your lens, which leads to diminishing sharpness. This, therefore, also leads to light loss. Luckily, macro lenses account for this difference in the lens markings. However, if you are attempting to use a normal lens for close up photography, you will need to compensate for the disagreement between your light meter and your lens. Some in-camera meters will show you the effective close up aperture in the viewfinder. Otherwise, you can find the appropriate corrections in Kodak's Photo Guide. The difference could be as drastic as a full 2 stops.
Step 3: Diffusing Contrast
Exposing an object that has both blacks and whites can get tricky. If you go too dark, then you lose detail in the blacks, and if you go to light, then you blow out the whites. Attempt to soften your light sources. This will help eliminate the hot spots and in general diffuse the contrast of your subject. Adding some return bounce fill will also help. However, no matter what you do, black will always be black.
Step 4: Bracketing
Even with a diffuser, you still could have problems exposing both the blacks and the whites in a single shot. If you are photographing something static, then there may be a solution. Using some Photoshop tricks, you can combine multiple exposures into a single shot. Set your camera on a tripod and lock it off firmly. Set your F-stop 1 stop under general exposure and take a shot. Then, without moving the camera, carefully reset the stop to the recommended F-stop and take another shot. Now, open up one more stop and take one final shot. If you move the camera while doing this, it will not work. You can now use Photoshop to take the blacks out of the more brightly exposed shot, and insert them into the shot with the best exposed whites.
Exposure is not so easily predicted in macro photography. There are some unique factors to consider, but most of these concepts are merely magnified by the level of detail in the subject matter.Popular P&S Cameras for High Quality Photos: