Image Blur: The Opposite of Sharpness
Let me tell you a secret: You don’t always need tack sharp photographs. Sometimes a soft focus image is just what the doctor—or photographer—ordered and blur and selective blur, especially in a black and white image, can add a film noir touch to an otherwise ordinary photograph.
When all or part of a photograph lacks sharpness, it’s blurry. That can be caused by camera or subject motion or can be accidentally or deliberately created by an object that’s in motion while the camera’s shutter is open, by moving the camera, or both. Making photographs of headlights and city lights while riding in a car at night and using slow shutter speed settings, for example, is an age-old technique for creating streaking light images
Another classic trick for creative blur is the “zoom during exposure” technique. Set your camera at a slow shutter speed, start to zoom the lens, press the shutter, and keep zooming during the entire exposure. This technique takes some practice but is easy to do especially with a digital SLR because you can immediately see the results and adjust exposure accordingly. The above photograph of the Akihabara district of Tokyo was made at 1/8 sec at f/22 in Program mode and with a minus one and one-third exposure compensation to punch of the colors. Lens was a Canon EF 18-55 mm zoom.