How to deal with handheld camera shake
Whether your goal is to freeze fast action or to take a sharp photo of a relatively static scene (such as a landscape or family portrait), it’s helpful to understand that motion blur has two distinct types:
- blurring caused by fast subject movement
- blurring caused by movement of the camera
Motion blur caused by movement of an unstable camera is commonly called camera shake and is distinguished by the fact that it affects every part of the composition equally. Camera shake is most often associated with handheld photography. Your breathing, heartbeat, and muscle tone all contribute to some individual base level of unsteadiness, in addition to the vibrations caused by mirror and shutter shock. Thus, when taking a handheld picture, the camera is always slightly unsteady.
The amount and presence of camera shake in your photos are determined by your shutter speed and focal length. Focal length is a significant factor in camera shake because narrower angles of view magnify the motion of your camera as its view wavers across the scene. Shutter speed is a factor because it can either capture a shorter or longer period of that motion. In general, you’re less likely to notice camera shake when using a faster shutter speed and shorter lens focal length, and you’re more likely to notice camera shake when using a slower shutter speed and longer lens focal length. The minimum shutter speed formula describes the slowest shutter speed and focal length combination that you can use while safely avoiding motion blur caused by camera shake:
1/(effective focal length)
Using this formula, you can determine that a 200 mm lens can be used at a shutter speed of 1/200 second, a 50 mm lens at 1/50 second, a 24 mm lens at 1/25 mm, and so on. In situations where the reciprocal of your focal length doesn’t have a corresponding shutter speed, select the next fastest one. If your camera has a very high-resolution image sensor, or if you intend to make huge prints, considering altering the formula in the following way to ensure clear results:
1/((effective focal length) × 2)
Camera shake and optical image stabilization
Optical image stabilization, or OIS, is an umbrella term for techniques that aim to reduce the motion blur associated with camera shake. OIS goes by different names depending on the manufacturer of the camera: Image Stabilizer (Canon), Vibration Reduction (Nikon), Optical Image Stabilization (Fujifilm), In-Body Image Stabilization (Olympus) MegaOIS (Panasonic), SteadyShot (Sony), Shake Reduction (Pentax), and so on. Regardless of branding, there are two main categories of OIS, lens-based image stabilization and sensor-shift image stabilization.
Lens-based image stabilizers employ a floating lens element that moves horizontally or vertically about the lens axis to compensate for angular movement and vibrations detected by a pair of accelerometers. Lenses with lens-based image stabilization are more complicated and expensive than similar models without it. The main advantage of lens-based systems is that the image projected into the viewfinder is also stabilized, which aids accurate framing.
In sensor-shift imagine stabilization, the image sensor is mounted on a moving platform powered by an actuator that compensates for the movement and vibrations detected by accelerometers in the camera body. The sensor-shift method keeps the image sensor aligned to a fixed point in the projected image by precisely measuring the angular and rotational velocities induced by camera shake. This is complicated by the fact that the system must tailor the degree of compensation to match the focal length of each lens. The main advantage of sensor-shift systems is that they work with unstabilized lenses, including a potentially huge archive of vintage lenses, so long as their image circles are large enough to accommodate the image sensor’s corrective movements.
Manufacturers measure the effectiveness of their OIS systems using photographic stops. Stops of stabilization describe how many stops slower you can safely set your shutter speed in comparison to that prescribed by the minimum shutter speed formula for your focal length. For example, if you’re using a 200 mm lens and your OIS system offers three stops of stabilization, you should be able to take pictures at a shutter speed of 1/25 second safely ((1/200)×2^3)=1/25).