We have gotten so used to looking at images on television, in newspapers and on smart phones that it’s often a shock to see a truly sharp print at an exhibition. A sharp image can dazzle the eye so unexpectedly that we may feel we’ve never really looked at things that way.
That’s why professional photographers and serious hobbyists devote considerable thought and energy to achieving the sharpest image possible. Here are some things to keep in mind if you want to achieve a sharper image:
Equipment. Modern DSLR cameras are amazing instruments and you will get good results with any of them. In general, I tell students to use the camera they already have and to upgrade as they realize they want something better. If you’re just getting started, buy the best camera and other gear that you can afford.
For the purpose of sharpness, pay special attention to the quality of your lenses and get the best you can. In terms of sharpness, it won’t make a noticeable difference whether you use a good, currently-made zoom lens or a prime lens; and the same is true whether the lens is faster or slower. (A fast lens allows you to work in lower light.) The only lens type I would advise against is a super-wide angle, which tends to lose sharpness at the corners.
Then get to know your lenses. Check them out and find out where they are sharpest and where they tend to soften an image. For example, I know that my Fuji 10-24mm lens is sharp throughout its range while my Fuji 55-250mm or my Nikkor 28-300mm lenses lose some sharpness when used at their widest settings. Since I like these lenses, I avoid using them wide open in low light. Instead, I compensate for low light by raising my ISO, which lets me shoot with a smaller aperture.Just keep in mind that raising the ISO will increase “noise,” which will soften your image slightly. In low light, you may have to weigh whether to raise your ISO or open your lens a stop or two. That’s why knowing how your lenses behave is so important.
Also, as you enter the settings on your camera in preparation for a shoot, one of your options is to use RAW or J-PEG to control the resolution of your images. RAW images will give you the highest resolution but each image will need lots of memory because of the large number of pixels. JPEGS take up much less memory but have lower resolution. A good compromise is to use the FINE J-PEG setting.Finally, keep your lenses clean. Get in the habit of cleaning your lenses at the end of each day or more often if you’ve been outdoors in a windy or sandy environment.
Depth of field. Depth of field refers to the extent of sharpness from near to far, something you should learn to control so you get the degree of sharpness you want in an image. Wide angle lenses offer a greater depth of field, keeping foreground and background sharp. Telephoto lenses have a shallower depth of field and will limit the extent of sharpness from foreground to background. Also, with any lens, the smaller the aperture, the greater the depth of field.
When shooting landscapes, we generally want great depth of field, with the image sharp throughout the scene from foreground to background. Therefore, it would make sense to use a wide angle lens and select a small aperture (f/16 or more). Also, focus on a point approximately one-third up from the lower edge of your image, slightly below any foreground objects, to maximize depth of field.
But, if for aesthetic purposes you want limited sharpness — for example a portrait taken on a city street — use a normal to telephoto lens, get close to your subject and shoot at f/2.8-5.6.
Aperture and shutter speed. The raw material of any photographic image is light. Your camera’s aperture setting controls the size of the shutter opening while the shutter speed controls how long it will remain open. Together these two settings determine how much light will register to create the image.
Sharpness comes into the picture because the aperture setting also controls depth of field while shutter speed also affects how movement registers. To maximize sharpness, you would generally want to use a small aperture (f/16-22) and a fast shutter speed.
But how fast is fast when you are dealing with tiny fractions of a second? It’s very hard to create a sharp image, especially with a hand-held camera, using a shutter speed of less than 1/60 of a second. A shutter speed of 1/60 or 1/125 of a second is usually fast enough to freeze the movement of a person walking. For sports photography, you’ll need a shutter speed of 1/500-1/1,000 of a second.
Of course, life is full of trade-offs, including in photography. To accommodate super-fast shutter speeds, you will probably need you to raise the ISO, which will increase the noise factor. Still, a little bit of noise is usually preferable to a badly blurred image.
Also, a lot depends on your aesthetic preferences and your personal vision. For example, many professionals opt for the smallest f/stops to maximize depth of field and sharpness in their landscape shots, even though this may mean working with a slow shutter speed. The solution mount the camera on a tripod.
On the other hand, there are many pros who prefer to achieve sharpness at aperture settings from f/5.6 to f/11 because lenses are designed to be sharpest at the mid-range. Or, in some instances, they want to limit the depth of field with wide open apertures — f/1.2 to f/5.6 — so only part of the scene is sharp. (More on selective focus in an upcoming article.)
Focus. Today’s electronic DSLR cameras can make almost every aspect of photography automatic. They can set the correct exposure, white balance and focus for you. However, cameras are not infallible, especially when it comes to focusing, which is key to achieving sharpness. There are times when auto-focus is the way to go and others when you should opt to focus manually.
For example, if your subject is fairly large, in the center of the frame and relatively close to your camera, auto-focus will work very well. But if your subject is relatively small, placed to either side of the frame or lacking in contrast, the camera’s sensor will have trouble locking in on your subject so you’d be better off focusing manually.
For manual focusing, rotate the lens barrel until the image is sharp where you want it to be sharp. You can see the results you’ll get by looking through the viewfinder or, even better, use your LCD monitor if you have a live view option. You can even use the magnifying button on your camera to focus on the specific area that matters most to you. When everything you want is sharp, take your shot.
You’ll need to hone your skills even if you opt to use auto-focus. That’s because only you know what you want in sharpest focus and you have to communicate that to your camera.
In most cameras with auto-focus, you’ll find a grid of dots when you look through the viewfinder. Once you’ve composed your shot, you’ll need to highlight one of those dots to indicate the point you want in sharpest focus. If your camera is set for auto-focus and you don’t highlight any of the dots, the camera’s default will be to focus in the middle of the frame and on a subject closest to the camera. (For older cameras that don’t have such a grid of dots, you can achieve the same results by putting your subject in the center of the frame, partially depress the shutter release to lock in the auto-focus setting, then, keeping the shutter release partially depressed, recompose your picture and press down until the shutter clicks.)
One last point: most of today’s cameras give you a choice of single auto-focus or continuous auto-focus mode. Use single auto-focus mode unless your subject is moving. For moving subjects, such as children running, birds flying or any action sports, continuous auto-focus mode will give you a burst or sequence of images, with your camera automatically refocusing for each image.
Movement. The most challenging factor to getting sharp images is movement, whether it’s the motion of a flower swaying in the breeze or the almost imperceptible vibration of hand-holding a camera or even the minute jostle caused by mechanisms in your camera. You may not be able to completely eliminate all these movements but you can take steps to reduce. First, use a tripod. Placing your camera on a sturdy tripod goes a long way toward overcome an unsteady hand. This is especially true when using shutter speeds of 1/60 of a second or slower, as you may do when photographing landscapes.
What’s more, a tripod makes composing and focusing much easier since you don’t have to concentrate on holding the camera. I recommend the Gitzo Traveler carbon-fiber tripod because it’s light and strong and fits comfortably in a regular suitcase if you are traveling. I’ve had mine for 20 years and it’s still going strong. Many of my students use a Benro tripod and like it very much. Another good option is Manfrotto.
Even if you’re using a tripod, you may cause the camera to shake or vibrate by depressing the shutter. So use a cable or remote release, or set the camera’s self-timer. Otherwise, press down on the camera at the same time as you depress the shutter release.
Also, most DSLRs have an internal mirror that bounces light up into the camera mechanism so you can see the image through your viewfinder. When you release the shutter, this mirror moves out of the way as the picture is taken. As it moves up and down, the mirror can cause some vibration that may affect the sharpness of your image. To prevent this from happening, you can lock the mirror in place after you are satisfied with your composition, focus and other settings. Using the mirror lock is especially important in super high-resolution cameras like the Nikon D810, Canon, Sony, Fijifilm, Hasselblad, Pentax, and Mamiya.
If it’s not possible to use a tripod, take advantage of the image stabilization feature in your camera or lens. This feature steadies the camera so you can use a slower shutter speed — some say up to four f/ stops slower — and a smaller aperture to maximize your depth of field.
And keep in mind that your choice of lenses will affect sharpness to some extent. In general, shorter focal length lenses — 24-50mm — are less likely to show the effects of camera shake while longer lenses — 100-400mm — are likely to magnify them.
What if it’s your subject that’s moving? You can manage to get a sharp image in several ways. First, you can use a shutter speed fast enough to freeze the movement — 1/125 of a second or faster, depending on how fast the motion is. If you’re shooting close-ups of flowers and the wind is tossing them back and forth, watch for the split second before the flowers switch direction. This takes patience and practice to get it right. Or you may be able to block the wind to some extent. Alternatively, try using an off-camera electronic flash to help stop the movement.
In upcoming articles, we’ll explore how to use after-capture techniques to manage sharpness and how to create aesthetically fascinating images without sharpness.
