You'll need some sunlight and some water and maybe a breeze to complete the next assignment. The term "bokeh" or "circles of confusion" [COCs] refers to out-of focus picture elements; details, if you will, that are placed beyond the range of your current mash up of ƒ-stop, focal length and shutter speed. Generally, circles of confusion are considered a good thing when integrated into a composition. Bokeh is derived from the Japanese term ボケ meaning blurry.
Next time your glasses, goggles or sunglasses get sprinkled on look towards a bright spot in the sky and try focusing on the water droplets. What you'll see are COCs in the raw.
Creating circles of confusion is relatively easy as long as you keep a few things in mind. First of all, wide-angle optics are not suitable for making circles of confusion for the simple reason that most wide-angle lenses are crisply focused from a meter or so in front of the lens to infinity and beyond. My fisheye starts focusing 3 cm from the front of the lens and never stops again. Telephotos and the longer zoom lens focal lengths are ideal for making circles of confusion. In fact, the longer the focal length, the better though maximum aperture has a role to play as well.
To make COCs, put on your longest lens and head to the beach on the next sunny day, positioning yourself so you'll be able to shoot towards the sparkling highlights dancing on the waves. Choose a subject -- a person, a bird, a bottle, a charging stegosaurus -- in the foreground that you can easily line up with the highlights dancing in the distance. You may have to shoot from a low angle to do so.
Next, switch your exposure mode to Manual [M] and set your aperture wide open, controlling the light with the Shutter Speed only. Review the Manual Exposure section of your camera manual before heading out. Mastering this is an exceedingly important step in your development as a photographer.
Limiting the light can be challenging on an exceedingly bright day. If your fastest shutter speed is not fast enough, one workaround is to change your ISO to 100 to reduce the sensitivity of the sensor. Try also, underexposing by a full stop or more by using the [+/-] Exposure Compensation Button. If that still doesn't work use your subject to block out some of the light reflecting off the water. You can also recompose, lining up the edge of the sparkling area instead of the middle.
Work fast and do not stare at the water highlights as they can permanently damage your eyes. On Nikon digital SLRs you can adjust the meter without looking through the viewfinder. Instead, use the the meter displayed in the LCD panel on the top, right of the camera body when exposure mode is set to Manual.
When all is set up -- subject sharply focused, aperture wide open, exposure set -- quickly compose and take the shot.
Circles of confusion occur under many conditions, not just when sparkly water is used as a background. They can be used, for instance, to soften the crowds in a stadium, separating the action from the distraction. COCs are very useful in night photography for the same reason. They can also provide a pleasant backdrop for outdoor portraiture. One note: The circles of confusion that are created by mirror lenses -- bright, out-of-focus bagel-shapes -- are generally considered unsightly and distracting.
I had to wade knee-deep into the water to line up the background highlights with the main subject. I spot-metered on the highlights, focused on the subject -- a mossy outcrop offshore from Murcheson Island in the Queen Charlotte Islands -- and snapped. The low-key foreground contrasts nicely with the bright pattern of circles behind it.
Here, glinting surface bubbles from a tiny tributary form increasingly flat circles of confusion as they move away from the point of critical focus. Photo mags and how-to books will tell you that you need a polarizing filter to take this shot. Personally I like the glare off water, any surface really, and consider it just another design element that can be used to enhance a photographic statement. In this shot, sockeye salmon rest, taking advantage of the camouflaging properties of the surface glare in the Adams River. This was taken during a banner year, when record numbers of sockeye returned to their birthplace to spawn. This cutline was written in autumn 2009, when the sockeye failed to return for the first time ever. You can bet humanity's inhumanity lies at the root of it.
Also taken at the Adams River. Note how a slight shift in positioning in relation to the sun causes the surface glare to vanish: no polarizing filter required.
Bokeh effects can be achieved with any brightly stippled subject from rain drops to foliage to window panes to the automobile headlights pictured here. A certain amount of contrast is required.
All photographs were taken by Brian Grover.