Transcript Bokeh By Denise O’Brien The art of shallow depth of field. This information comes to you from a wonderful article that was posted.

Bokeh
By Denise O’Brien
The art of shallow depth of field.
This information comes to you from a wonderful article that was
posted by the folks at AdvancedPhotography.net. This post
describes the process of coming up with photographs that have
the distinctive out of focus light circles scattered about the
photograph, which is called Bokeh. The word “bokeh” comes
from the Japanese word “boke” (pronounced bo-keh) which
literally means fuzziness or dizziness.
Any way you say it.
The English spelling bokeh was popularized
in 1997 in Photo Techniques magazine,
when Mike Johnston, the editor at the
time, commissioned three papers on the
topic for the March/April 1997 issue; he
altered the spelling to suggest the correct
pronunciation to English speakers, saying
"it is properly pronounced with bo as in
bone and ke as in Kenneth, with equal
stress on either syllable".
The spellings bokeh and boke have both been in use at least since
1996, when Merklinger had suggested "or Bokeh if you prefer." The
term bokeh has appeared in photography books at least since 1998.
It is sometimes pronounced /ˈboʊkə/ (boke-uh).
Bokeh is the photography
technique of aesthetically
blurring the background and
to exaggerate the effect of
the lights shinning in the
background or the
foreground. The bokeh effect
does wonders by adding a
surreal perspective to your
captures — it adds the third
dimension of depth missing
from the two dimensional
images. It not only helps in
eliminating the cluttered
background; but it also helps
display the background
elegantly.
1. Glowing Background Is
The Essence Of Bokeh
The bokeh effect is
nothing more than the
presentation of scattered
lights (or any vibrant
pattern for that matter)
visualized by the lens of
your camera. The
background should be
brighter or comparable to
the subject itself. You will
not be able to get the
desired effect in low-lit
background.
2. Equipment & Accessories Required For Creating Bokeh
Effect
The bokeh effect or the blurring effect is not easily attained by
the normal point and shoot cameras or the handy compact
cameras. The effect is generated with a narrow depth of field
and high zoom factor.
• Digital SLR over the regular point and shoot cameras.
• Zoom lenses with high zoom factor to effectively focus the
subject and to deliberately blur the out-of-focus subject (the
glowing background).
• Consider using a tripod; to compensate for slow shutter
speeds.
3. Aperture Priority Mode: The simple way to attain a narrow DOF
is to set your camera to “Aperture Priority” mode. Use the largest
aperture opening available by setting the aperture to the lowest fnumbers (to attain a wide aperture). The shutter speed could be
very slow that is why a tripod is recommended at times.
Focus: Manually set the
focus (the auto focus can
be tricky when there is no
subject to focus).
Full Zoom: The high zoom
factor provides maximum
focus on the subject
thereby eliminating the
Details in the background.
4. Bokeh Is Inversely Proportionate To Subject’s Distance
Try to minimize the difference between the camera and the
subject to attain a shallower DOF. The closer the subject; more
the chances of blurring the background; thus, more of out-offocus effects.
To summarize:
Here are some
tips to get you
started with
bokeh
photography.
1.) Larger aperture works best, so
use a low f-stop number like f1.4,
f1.8 or f2.8
2.) Set your camera to aperture
priority.
3.) You would need to set the
shutter speed faster than 1/50
second. Any slower and the
background lights getting blurred
together, instead of rendering
small circles. If it’s too dark,
increase the ISO level rather than
the f-stop number.
4.) The closer you get to subject, the better. If you’re
using a zoom lens, extend it to the longest focal length.
5.) The further away the background, the better.
6.) Ensure that the background is lit. Glowing lights like
street lamps and traffic lights work best. While a
consistently lit background would just create a regular
blur.
7.) If you don’t have a subject and want to create the
bokeh effect with the night lights, manually focus your
camera.
Shoot into
the sun.
A shallow depth of field, such as f/1.8 produced by a Canon 85 mm prime lens, caused
the polygonal shapes of the 8 bladed aperture diaphragm. If at the full aperture, these
shapes would be smooth and not polygonal.
The shape of the aperture has an influence on the subjective
quality of bokeh as well. For conventional len designs (with bladed
apertures), when a lens is stopped down smaller than its maximum
aperture size (minimum numbers, out-of-focus points are blurred
into the polygonal shape formed by the aperture blades. This is
most apparent when a lens produces hard-edged bokeh. For this
reason, some lenses have many aperture blades and/or blades with
curved edges to make the aperture more closely approximate a
circle rather than a polygon.
This particular lens has 5 aperture blades, so when it is stopped down
the aperture is pentagonal. Better lenses often have more aperture
blades, and those blades are often curved so as to give an aperture
that's closer to being circular. Very cheap cameras may use 4 or even 3
blade apertures resulting in square or triangular out of focus highlight
which do not create good bokeh.
Note though that a perfectly round aperture is no guarantee of good
bokeh.
The following comes from Bob Atkins.com. If you want
more info to to his website.
What determines how blurred distant background objects are is
the physical size of the lens aperture. This is simply the focal
length divided by the f-stop, so, for example, a 50mm lens used
at f4 has a physical aperture of 50/4 = 12.5mm.
For a lens that's focused on a nearby subject and when the depth
of field is fairly small:
The degree of blur of objects close to the main subject is
determined by the f-stop of the lens in use. The faster the lens,
the smaller the depth of field, the greater the local blur.
The degree of blur of objects FAR behind the subject is given by
the physical size of the aperture of the lens in use.
The degree of blur at intermediate distances behind the subject
has to be calculated. There are no simple rules, except that it's
more for fast lenses with large physical apertures.
At the same magnification, the faster the lens, the smaller the
depth of field. This also means that the background close to subject
will be blurred more by the faster lens. In this case the 50mm lens
at f1.4 gives slightly greater blurring for objects up to about 1m
behind the subject in focus. However as you go further back, the
lens with the largest physical aperture starts to show the most blur,
and by the time you're at infinity, the 135mm lens at f2 lens will give
almost twice as much blurring. The following images show the
effect quite clearly.
All three were shot to produce the same magnification of the
camera box and so you have essentially the same depth of field
(region of "acceptably sharp" focus), but the image shot with the
larger physical aperture (longer focal length) lens shows the
greatest degree of background blur.
Following images by
Andrea Monninger
shot at Parklands and
Funks Grove
Following image by
Vandana Bajikar