At this point, nearly every camera manufacturer has incorporated something into their cameras to reduce the blur that’s caused by camera shake. It goes by an alphabet soup of abbreviations, depending on the manufacturer: VR (Nikon, “Vibration Reduction”), IS (Canon, “Image Stabilization”), OS (Sigma, “Optical Stabilizer”) and a host of others. While many manufacturers build this feature into the lens, a couple (like Pentax) build it into their bodies, so that no matter what lens you’re using, it should help.
Here’s a layman’s explanation of how it works. You’ve got small gyros* in the camera which sense camera motion; these movements are then communicated to a processor, which will essentially instruct small motors in the lens to move lens elements (usually in groups) to compensate for that motion. Some manufacturers claim up to a four-stop improvement in camera shake, which I think is great marketing hype, but too optimistic. More realistically, it’ll take care of a little bit of shake (minor instability), but not that much (if your hands are about as still as the average earthquake).
So what if neither your lenses nor your bodies have some kind of image stabilization built in? Well, this is where it helps to take a cue or two from film shooters, who generally didn’t have any of this fancy stuff either. Your first, and best, solution is a support, whether in the form of a tripod or monopod. If you’re using a timer, shutter release cable or a wireless remote, you don’t even have to worry about touching the camera at all once it’s mounted.**
There are going to be times when a support’s impractical, or you just don’t have one handy. There’s a simple rule that should eliminate most of your camera shake, and give you nice, sharp photos (provided you have a reasonably steady hand). The reciprocal of your shutter speed should be the same as the focal length you’re shooting with. So if, for instance, you’re shooting at 105mm, you should be fine with a shutter speed of 1/125. At 200mm, you’d want to shoot at a minimum of 1/200.
There’s a slight wrinkle here if you’re shooting with a cropped (non full-frame) sensor; the crop factor acts as a magnifier/multiplier, so that 105mm is actually behaving like a 155-160mm, and a 200mm will give you a magnification closer to that of a 300mm. This is a double-edged sword, since on one hand, you’re getting a bit of extra reach (think of it as a built-in teleconverter), but on the other, you’ll also have to shoot at higher shutter speeds as a result (1/320 on a 200mm lens versus 1/200).
This is all fine and dandy in daylight. After all, shooting Sunny 16 at ISO 200 will give you enough shutter speed to keep your images nice and sharp with many lenses. But if the light’s a bit iffy, your other settings will start to come more into play; you may need to tweak either your aperture or ISO (or both) in order to get a higher shutter speed.
Image stabilization’s a great option to have, but it’s not going to solve every stability issue that comes down the pike. Using your shutter speed (in conjunction with your other settings, if you’re feeling adventuresome) can be a good supplement to, or even replacement for, the image stabilization you’ve already got. Otherwise, a support – whether it’s your trusty tripod, or just leaning against a tree – will work wonders.
*Those would be gyroscopes, not tasty Greek sandwiches. That would be awkward and messy.
**I should mention that if you’ve got a stabilized lens or body and you’re using a tripod, you’ll want to shut it off. It can actually lead to your photos being less sharp if used in conjunction with a tripod, for one thing. For another, depending on how your body/lens works, it may lead to a slightly faster battery drain, since the camera’s going to be trying to stabilize the image whether it needs it or not.