Know your camera’s limits

Match the tool to the picture-taking task

Do you know your digital camera’s strengths and weaknesses? They can vary so let’s look at a few critical areas to make sure you aren’t losing image quality because you aren’t compensating for your camera’s weaknesses.

Match megapixels to task
How many megapixels does it have? The more megapixels it has the more loosely you can compose a picture and crop it later in Adobe Photoshop, giving yourself more options. But if you regularly make enlargements 11 x14 or bigger, you’ll need to compose tightly and minimize post production cropping.

Fast focus
Some camera-lens combinations can focus really fast for action photography. Not mine. I don’t have a true sport lens. So when the sport allows it, I try to prefocus where the action will occur. That way I don’t lose shots to bad focus because I’m too cheap to buy a $2,000 lens that can rapidly change focus even with super fast action.

My camera reveals heavy noise when I shot at ISO 640 at this bonfire.

Image noise
Image noise is the distracting appearance of random pixels, usually colored, that seem to pepper your image like confetti. It most commonly appears in pictures taken at higher ISOs—400 and up—and longer exposures—several seconds and longer. The newest dSLRs have greatly reduced noise so its impact is minimal up to ISO 800. But test your camera for its noise performance at ISO 200, 400, 800, and 1200, and at exposure times one half second to four seconds. Try to avoid those ISOs and exposure times that offer unacceptable results.

White balance
Using the RAW mode can minimize white balance problems but for casual photography you may often use the JPEG file format. White balance problems typically show up under artificial lighting, such as tungsten and fluorescent lamps, or mixed lighting. But even in daylight, certain colors or color combinations dominating a scene may confuse your camera’s white balance system. My automatic white balance is okay but I get better results when I set the white balance to match the scene lighting.

Test your camera at different white balance settings, including automatic white balance. During the test place a white sheet of inkjet paper in the scene. If it appears on the computer monitor as a neutral white (and is verified by Photoshop when you place the cursor over it and look at the RGB values (they should be roughly equal) under Window>Info then you’re in good shape. If it shows too much color, create a custom white balance setting (see your camera manual) for any lighting situation you commonly photograph in.

Exposure Accuracy: You should get at least a basic read of the accuracy of your camera’s exposure system. Varying exposure by ½ stop, take a series of pictures of an “average” scene that your camera should easily be able to handle. Look at the camera’s histogram or at the Photoshop histogram to determine if your best exposure is the camera’s recommended setting.

Handholding for sharpness
Subtle camera movement from handholding it at slower shutter speeds translates to subtle picture blur—perhaps the biggest destroyer of image quality. Using a tripod is the best answer, but assuming you don’t always use one, you should determine the slowest shutter speed at which you can handhold your camera and get good results. For image stabilized lenses, take pictures at shutter speeds 1/4, 1/2, 1X, and 2X the focal length of your favorite lens (for example, for a 100 mm lens, take pictures at 1/25, 1/50, 1/100. and 1/200 sec).

For a non-stabilized lens, take pictures at shutter speeds 1X, 2X, and 4X the focal length of the lens (for a 100 mm lens, take pictures at 1/100, 1/200, and 1/400 second). Take pictures of a subject that’s fairly flat, and has some distinct lines that you can evaluate. Review the images at 100% in Photoshop by double clicking the magnifying icon and determine the optimal shutter speed for handholding the camera at that focal length setting.


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