Bokeh

The quality of the out-of-focus area in a wide-aperture image is called bokeh, originally from the Japanese word boke, pronounced bo-keh, which means fuzzy. In photography, bokeh reflects the shape and number of diaphragm blades in the lens, and that determines, in part, the way that out-of-focus points of light are rendered in the image. Bokeh is also a result of spherical aberration that affects how the light is collected. Although subject to controversy, photographers often judge bokeh as being either good or bad. Good bokeh renders the out-of-focus areas as smooth, uniform, and generally circular shapes with nicely blurred edges. Bad bokeh, on the other hand, renders out-of-focus areas with polygonal shapes, hard edges, and with illumination that creates a brighter area at the outside of the disk shape.

Shooting with natural light, I used a long lens (200mm) to compress the space and slightly blur the background by photographing at a large open aperture (f/2.5). This resulted in gorgeous bokeh, putting the city into a blur while keeping the couple razor sharp.

More expensive lenses usually go down to f/2.8, letting you shoot at faster shutter speeds and get great, creamy bokeh in your background.