Bokeh refers to the aesthetic quality of blur in out-of-focus areas of an image produced by a lens. Factors like lens aberrations and aperture shape determine the pleasing or unpleasing way a lens renders out-of-focus points of light. Photographers sometimes use a shallow depth of field to emphasize out-of-focus regions and produce prominent bokeh. Deep focus, in contrast, keeps the entire scene in sharp focus from foreground to background. Shallow focus uses a small depth of field to emphasize one part of an image by blurring the areas around the in-focus subject. Rack focus, or focus shift, is a cinematography technique that changes the focus during a shot to direct viewers'

1. By
Pradeep Kumar Gupta
Dept of Animation , CCSIT, TMU

2. In photography, Focus effect or bokeh is the aesthetic quality of
the blur produced in the out-of-focus parts of an image produced by
a lens. Bokeh has been defined as "the way the lens renders out-of-
focus points of light".
Differences in lens aberrations and aperture shape cause
some lens designs to blur the image in a way that is pleasing to the
eye.
Bokeh occurs for parts of the scene that lie outside the depth of
field. Photographers sometimes deliberately use a shallow
focus technique to create images with prominent out-of-focus
regions.

3. Bokeh is often most visible around small back ground highlights,
such as specular reflections and light sources, which is why it is
often associated with such areas. However, bokeh is not limited to
highlights; blur occurs in all out-of-focus regions of the image.

4. Deep focus is a photographic and cinematographic technique
using a large depth of field. Depth of field is the front-to-back range
of focus in an image—that is, how much of it appears sharp and
clear. In deep focus, the foreground, middle-ground, and
background are all in focus.

5. A film utilizes deep space, when significant elements of an image
are positioned both near to and distant from the camera. A deep
space film shot utilizes deep space when the subjects of an image
are positioned both close to and far away from the camera.
While not all subjects have to be in focus, all of them have to be in
frame and lit visibly. Deep space is achieved when the mise-en-
scene is carried deep into the frame. Actors and objects are placed
in particular places to draw the eyes in every direction.
The deep focus shot utilizes this space. The lighting in this
scene favors all of the elements of the scene. You’re able
to search for emotional depth and story elements in each
character’s placement throughout the frame.


6. Shallow focus is a term referring to the technique that keeps one
part of an image in focus while the rest is out of focus. Shallow focus
uses a shallow depth of field by either widening the aperture,
increasing the focal length of the lens, or placing the camera closer
to the subject to create blur. It is blurring the background and
foreground around the sharp subject. It helps emphasize one part of
the image over another to draw the viewer's eye to a particular area
of the frame or subject.

7. To understand what shallow focus is, you need a firm grasp on
some other photographic elements like depth of field and aperture.
Make sure you’re well-versed in these:
Aperture is a lens setting that affects depth of field.
Depth of field is the area of acceptable sharpness in front of and
behind the subject on which the lens is focused. It essentially
refers to how blurry or sharp the area is around your subject.
The camera’s aperture controls this blurriness and sharpness
by adjusting the size of the opening in the lens.
A shallow depth of field describes the small or narrow area
that is in focus. Often, the background is blurred while only the
subject stays in focus. This shallow or small depth of field can
be achieved by increasing the aperture or rather lowering the f/
number.

8. Focus Shift
Also called as rack focus in filmmaking and television
production is the practice of changing the focus of the lens during a
shot. The term can refer to small or large changes of focus. If
the focus is shallow, then the technique becomes more noticeable. In
professional films, a camera assistant called a focus puller is
responsible for rack focusing. Have you ever been watching a movie
or TV show and noticed a subtle change in depth of field that
revealed some new detail in a scene? That’s a rack focus or focus
shift.

9.  The reason to rack focus is simple; you want to help direct the
audience’s attention to something in the scene. Therefore, the rack
focus shot can be crucial to pointing out details to the audience.
It could be to someone else in the scene. Or Racking Focus to
create tension. You can even change the tone of a scene. The rack
focus is a nifty tool that allows you to be completely in control of what
the audience takes away from that scene
Unlike other camera moves, the rack focus is able to be incredibly
specific. It’s almost like directing a spotlight onto a detail.