Dept of field is a powerful tool when taking macro images, and it’s a technique you’ll need to understand in order to work true macro magic. You’ll generally be using very shallow depth of field settings when getting up close to the subjects, and the closer you get, the shallower depth of field becomes.
At times this can be frustrating. For Example, you think you have captured a great image of a flower in full bloom, buth then find that parts of the image are too soft. One way of getting around this is to stand a little further back and use more zoom, but be prepared to pay the penalty in terms of camera shake.
A much better option is to adjust the aperture setting manually. Selecting a smaller aperture, such as f/16 or even f/32, will increase the depth of field and ensure that the subject stays sharp. Larger aperture settings, such as f/2.8, will provide sharp focus area that can be measured with millimeters.
However, as soon as the aperture gets smaller, shutter speeds start to get much longer in order to compensate for the reduced amount of lighting coming through the lens. At settings of ISO 100 and f/16, shutter speed will be roughly 1/60secs or even slower, which can be a bad news if you’re taking a hand-held shot because the risk of camera shake increases considerably.
You can still take the shot by using a tripod. You don’t need to get the biggest, heaviest tripod model you can find; if you choose a sturdy model, it is possible to leave the shutter open as long as you like. If a tripod is unavailable, steadying the camera against a wall, fence or even a camera bag will make things much less shaky.
Last tips, autofocus saves a great deal of time and hassle in norma shooting modes, but it’s often a good idea to use manual when shooting up close. Even the best AF can be fooled when working so near to the lens, so switching to manual is the best bet to ensure pi-sharp pictures every time.