CRASH COURSE
ESSENTIAL PHOTO SKILLS MADE EASY
Can’t get everything in focus? Adam Waring shows you how to focus-stack images for incredible front-to-back sharpness
A macro lens enables you to focus extremely close to a subject so that it’s reproduced at life-size on the camera sensor, opening up a world of incredible detail that’s impossible to see with the naked eye. The drawback is that at such close focusing distances depth of field becomes extremely shallow, and will be only a matter of millimetres even if you stop down to a narrow aperture – so all that detail is lost from all but a very narrow band of sharp focus.
The solution is focus stacking. Take a series of shots, each at a slightly different focus distance, then combine the images to include the sharpest elements from each shot. It sounds complicated, but all the hard work is easily done in software, and it’s a largely automated process.
You simply focus on the closest part of the image, take a shot, then twist the focus ring a tiny bit and take another shot, repeating the process until the most distant part of your subject is in focus. Some new cameras make things even easier with ‘focus shift’ shooting modes which automatically takes a series of shots, each at a slightly different plane of focus.
Macro photography is just one application of focus stacking; it can be used for any subject where you can’t get enough depth of field in a single frame, such as landscapes in which you can’t get both distant mountains and foreground rocks sharp without encountering diffraction, an optical anomaly that causes softening of images at narrow apertures. Here’s how we created the image above…
1 GET SET UP
We’re using a Sigma 105mm f/2.8 Macro lens, but any close-focusing lens works for this technique – even a kit lens, which can focus at around one-third life size. Use a tripod to keep your camera steady, with the subject positioned so that everything fits in the frame.
2 CAMERA SETTINGS
Switch to Manual mode so that each shot has the same exposure, and set an aperture of f/11 for optimum sharpness, along with ISO100 and a matching shutter speed. Flick the switch on the lens barrel to manual focus, and focus on the closest part of the subject.
3 GET FOCUSED
It’s best to use Live View. Zoom in to the closest part of the subject, and twist the focus ri
