Bokeh pictures How to make one easily

The casual study of a child at play in the next image was taken with a zoom set to 200mm, producing a fairly tight 6.9-degree AOV, and the exposure of 1/250th second at f/4 resulted in a limited depth of field. (The camera had a 1.5 crop factor.)

Notice the way the background starts becoming softly out of focus on the rocks and the reflections on the water are soft and smooth. This outof- focus effect is called bokeh. That’s a Japanese word that means “fuzziness.”

When the lens focuses the image on the sensor, the most precise focus is at a plane parallel to the sensor at the focus point. The objects at that point are rendered as very tiny circles. Objects that are not in focus are recorded as larger and less distinct circles.

The quality of lens bokeh varies with the optical quality and the shape of the diaphragm. It’s generally a good idea to try to keep the objects in the foreground in reasonable focus. Humans tend to accept a fuzzy background, but find an out-of-focus foreground distracting.

Shallow depth of field and bokeh at wide f/stops are natural characteristics of telephotos. They can be used creatively, just like the extended depth of field and sharp background of wideangle lenses. That’s what the TriCoast team did with the image of the organist in this image:

The Canon EOS 20D coupled with a 200mm lens produces a 6.4-degree AOV, yielding slightly more telephoto effect and even more bokeh because the photographer was closer to the subject and shooting wide open at f/2.8.

See how the edge of the hand and the numbers on the controls to the player’s right are in focus? Bokeh has rendered the organ keys in the upperleft corner almost a total blur. The arm starts getting fuzzy as it moves toward the sleeve. This shows something else about depth of field. It tends to be deeper behind the point of focus and not quite as much in front of the primary focus.

That’s what optical tests show. The range of depth of field in a wide-angle lens is a ratio of 2:3 to the back of the point of focus and 1:3 toward the front. In other words, the if the total depth of field was three feet, then it would extend one foot in front of the subject in focus and two feet behind it. The difference lessens as the focal length of the lens increases. So does the amount of the depth of field.

A 1000mm telephoto has a very shallow depth of field, and it is almost evenly distributed on both sides.

The shallower your depth of field is, and the longer the lens, the greater the bokeh effect. This technique is a very effective way to eliminate a distracting background and draw attention to the primary subject. Johan Aucamp use bokeh to produce a very pleasing background in the picture shown in the next image. The long lens, coupled with a wide f/stop, produced a very shallow depth of field.

The scene behind the bird was blurred into a pattern of color and vague shapes. Increasing the depth of field reduces bokeh, allowing more detail in the background.