In macro photography you should aim to capture a sharp image of your tiny subject with all — or nearly all — of the subject in sharp focus. Using a macro lens on a DSLR is the optimum way to travel. There is one more thing to be taken into account: you must keep the subject still and the camera must be locked off. For macro shots you need a steady camera and subject, a small lens aperture and a slow shutter speed. Then you need more light to cope with the slower shutter speed.
Keep Your Distance
In macro shooting the optimum camera-to-subject distance is a long one. Place the camera too close to the subject and there’s a good chance you’ll throw a camera shadow onto it; at too close a distance you may distort the subject. Using the macro mode on a compact or DSLR and wanting to capture a very, very close detail of your subject, it’s most likely you’ll move the lens to the widest angle/shortest focal length setting. This also presents the possibility of optical distortion.
Macro lenses for DSLRs are best chosen in the longer focal lengths: many lens makers market a 100mm macro — ideal for the task. Canon and others make stabilized macro lenses. The idea is sound in principle: if you have to handhold the camera/lens combo while you snare close shots of a bug, a stabilized lens would seem to be the answer to the need for a steady camera. The truth is that there are too many variables in the equation: moving camera, moving focus, moving subject. And then you have to frame the shot properly. The best approach is to keep the camera steady.
Viewing
When shooting macro with a digicam, always use the LCD screen for viewing — never use the optical viewfinder. Use the optical finder and you will encounter parallax error … what you see in the finder is not what the camera will photograph.
Distortion
Digital compact camera optics are a compromise between size and price. With budget cameras you will probably encounter spherical distortion: shots taken at the wide end (even in macro!) of the zoom will barrel out at the edges; shots taken with the zoom set to tele may show distortion which forces the picture edges to bow inwards, like a pincushion. Try shooting a square subject — like a stamp — and you’ll see. The solution is to use the Spherize filter in Photoshop to straighten the barrel distortion on the affected image.
Depth of Field
This is possibly the core factor in successful macro shooting. When you focus, the depth of field includes the plane you focus on plus an area in front of and behind that plane. Half of the sharpest area will be in front of the plane and half will be behind it. Depth of field varies with the lens aperture, focal length and the camera-to-subject distance. Competent use of it will give you a subject in pin-sharp focus with the background in soft focus: a soft focus background isolates a subject, making it stand out sharply.
No Confusion
Take care to position your macro subject against an appropriate background: no confusing fuzz, no bright spots; dark backgrounds for light subjects and vice versa.
Lighting
You've probably set up the camera only centimetres from the subject. Flash is useless at a close working distance — it would overexpose the shot. If you’re working in filtered daylight, you can help by scattering small reflectors around the subject. But in most cases you’ll have to live with the existing ambient light level. Arguably the optimum light for macro work is to set up a scrim of translucent material (like rice paper) over the subject. In this fashion you can shoot in bright sunlight, with the subject illuminated by soft light.
Light Loss
If you’re working with a DSLR you might like to use extension tubes or close up bellows to shoot macro. If you do, you will encounter one problem: the further the lens is extended from the image sensor the more you will encounter light loss, requiring the camera to use a larger lens aperture.
Focus
In macro photography it is advantageous to have full charge over focusing — especially when you want to have control over that part of the subject you want in focus. If your camera allows manual focusing, use it and manually focus on the part of our subject that is the main point of interest.
