Friday, November 30, 2012

Look sharp!

One factor that can have a significant impact on the quality of your images is how sharp they are. Sometimes I like being able to stand up close to a large print and enjoy the clear definition around the smallest details. Sharpness helps the images look more lifelike.

While there's also something to be said for the art of blurring away the fine details, producing sharp images is something that most nature photographers want to accomplish, at least some of the time. The quality of your equipment plays a big role in how sharp your images are, but so does your technique.

Here are some tips for getting the sharpest images out of the equipment you already own:

Use your tripod. If the camera is moving, even slightly, while the sensor is recording, your image won't be sharp. Heavier tripods provide the best support, but any tripod is typically better than trying to hold your camera perfectly still. The key to sharp images is to eliminate as much camera movement as possible.

Use a cable release or timer. Any time you touch the camera – even when it's on a tripod – you introduce the possibility for vibrations. And, again, if the camera is moving at all during your exposure, your scene will be a bit blurred. Using a cable release is ideal, but most often, I just use my camera's two-second timer. Even though I touch the camera to start the exposure, after two seconds, any impact from my touch has long since dissipated.

Use mirror lock-up, if available. If you use an SLR (cameras whose viewfinders show you exactly what's coming through the lens), search your menu options for something called "mirror lock-up." These cameras work by placing a small mirror in front of the sensor. When the mirror is down, you can see through the lens. But when taking a picture, they have to move the mirror up and out of the way. That rapid movement causes vibrations within the camera.

When you use mirror lock-up, taking a picture becomes a two-step process. The first time you press the shutter, the camera moves the mirror up. The second time, it actually takes the picture and moves the mirror back down.

Or, if you use the two-second timer, you just have to press the shutter once. When you press it, it lifts the mirror and starts the timer. After two seconds, it takes the picture and lowers the mirror.

While mirror lock-up does improve sharpness, do be aware that while the mirror is up, you won't be able to see through the viewfinder; it will be totally black. If you are trying to capture action, it is typically best to turn mirror lock-up off. I have used it in some cases, however, such as trying to capture waves crashing over a particular rock. In this case, I use a cable release instead of the timer. I press the cable release to lock the mirror up and then wait for the action. Do be aware that once you lock the mirror up, you typically have to take your picture within 30 seconds. The camera will not lock the mirror up indefinitely.

Remove your UV filter. Anything you add to a lens will degrade image quality somewhat. In the case of a polarizer, that loss of sharpness may be worth it because you gain a visual effect you can't get any other way. A UV filter doesn't really do anything for digital cameras, which aren't sensitive to UV light (some types of color film were, especially at altitude where there is more UV light).

Use f/7. The aperture you use will also affect image quality. Lenses are typically sharpest around f/7. At a tiny aperture like f/22, diffraction can significantly reduce sharpness. That doesn't mean you should never use f/22. It does maximize depth of field so things close to the camera can appear in focus along with things in the background. But if your scene doesn't have a tremendous amount of depth, try using a more open aperture, like f/7.

Sharpen during post processing. Most images also benefit from some sharpening in software. One of my last steps in Photoshop is to apply some Smart Sharpening (from the Filter menu, select Sharpen, then Smart Sharpen). The numbers can be confusing, but understand the larger the radius, the more extreme the sharpening. I like a subtle effect, so I usually use a radius of 0.8 or 0.9 at 70 to 80 percent strength.

There is a huge difference in quality between a $200 lens and a $2,000 lens. You generally get what you pay for. But taking full advantage of these techniques can help you maximize sharpness even from budget equipment.

(Follow Kevin Ebi's photography on Facebook, Twitter, or Google +.)

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