Tuesday, October 25, 2011
Solutions: Beat The Blur
Choose the best shutter speeds for sharp shots
The most frustrating occurrence in nature photography is returning home with a card full of images and finding that your prized shots are soft. It happens far too frequently, and it's positively demoralizing. You might think that the ability to instantly review on a DSLR's LCD would have long since prevented this from happening, but small LCD monitors, with their glowing screens and rich, saturated colors, can, in fact, give you a false sense of security about the sharpness in your images unless you zoom way in to examine the detail.
Softness occurs when either the lens isn't focusing properly or the camera or subject is moving and thus creating a blur. In this brief article, we're going to look at motion blur that's introduced from the camera and how to avoid it. Of all the potential elements of nature photography that can result in softness, camera shake is among the easiest to avoid. What's required is attention to detail.
Minimum Handholding Speed
The minimum handholding speed rule says to take the reciprocal of the equivalent focal length that you're shooting at and make that the shutter speed. For example, you have a 70-200mm lens on an APS-C DSLR and you're using it zoomed to 150mm, you'd have an equivalent focal length of about 225mm, so 1⁄250 sec. would be the minimum handholding speed. However, this is really more like a guideline than a rule because everyone is different, and some can hold a camera steadier than others. Using this guideline, it's a good idea to do some tests to see what works for you and be aware that, as you get to wider-angle lenses, things break down. We've never seen anyone who could get a sharp handheld shot at 1⁄20 sec. even when shooting at 20mm. Also, at very long focal lengths, things break down, as well. Handholding 800mm is nearly impossible. Be conservative.
The Tripod Or Other Support
This is a no-brainer. A tripod will hold the camera steady, so use one. Everyone knows this, and yet the tripod is always the piece of gear that gets left in the car. Besides using it, to be effective, your tripod and head should be sturdy enough to properly hold your rig. Also, beware of overextending the legs or center column. If there's a breeze blowing, you'll want to bolster the tripod by adding some weight, like your camera bag, which you can hang onto a hook or wrap around the legs. Even on a tripod, though, you need to be aware of your shutter speed, which leads us to the next point.
You can still end up with camera shake even if you're using a solid tripod and head on a day with no wind. When you trip the shutter on your DSLR, you're doing two things that can kill sharpness. First, you're depressing the shutter button, and second, you're making the mirror flip up and out of the way. Both of these actions can create a surprising amount of camera shake even when the camera is on a good support. There's a limited range of shutter speeds where this kind of camera shake is most noticeable—from about 1⁄8 to 1⁄30 sec. Within this range, use your mirror lockup function and the camera's self-timer to avoid blur-inducing camera shake.
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