Note the differences in the clarity of the higher resolution image versus the lower resolution image.
4TH YEAR, VIITH SEM
DOORDARSHAN KENDRA, JAIPUR
Doordarshan is an Indian public service broadcaster.
It is owned and operated by Prasar Bharati Broadcasting
It is one of the largest broadcasting organisations in India in terms
of the studio and transmitter infrastructure.
It was started in Delhi on 15 September 1959 as experimental,
and its regular transmission started in 1965.
Its Head office is located in New Delhi, India.
The DD provides television, radio, online and mobile services
Presently, Doordarshan operates 21 channels including DD
National, DD News and DD Sports.
The network features some original programming, such as
dramas, comedy-series, talk shows and re-runs of popular TV
shows from other Indian television channels.
Live Coverage of national events like Independence Day,
Republic Day Celebrations, Budget Presentation and other
happenings of national and international importance are
regularly carried on this channel.
DD Rajasthan is a state owned TV channel telecasting from
Doordarshan Kendra Rajasthan.
On 1 August 1975, the first television broadcast was viewed
by the people of Rajasthan under the Satellite
Doordarshan Kendra in Jaipur was set up on 1 June 1987 at
Jhalana Doongri and transmission started on 6 July 1987.
Initially only 30 minutes of programming produced by this
Kendra and this was gradually increased. Presently the
Kendra originates about four hours of programming daily.
The channel covers 79% by population and 72% by area of
A TV Camera consists of
a) A Camera lens: It selects a certain field of view and produces a
small optical image of it on the face plate of pick up device.
b) A transducer or pick up device: To convert optical image into an
electrical signal. It is mounted inside the main head of camera.
c) View Finder:- It shows a small video image of what the lens is
Primary function of lens is to produce a
sharp image of object on the face of
To determine the magnification and size
of the image.
To decide field of view.
Changing distance from the lens to object
changes the size of the image and position of
the image plane
Focal length is the distance between optical
center of the lens (and not the physical center)
and the focal point.
Focal point is the point at which the light rays
converge at the rear of the lens to produce
perfectly focused image.
In a video camera it is the distance between
face of the pick device and optical center of the
Focal length will decide the amount of image
magnification and field of view.
Resolution: Number of pixels captured by image sensor.
Focus: To focus objects at various distances
3,4,5,7,10,15,30, infinity, in feet
Zoom: To take long(lowest focal length) and tight shot
(Highest focal length)
Aperture: To control the amount of light entering
F-stop: 1.4, 2.0, 2.8, 4, 5.6, 8, 11, 16, 22,
Back Focus: To keep long shot in focus while
Macro: To focus an object lying within Minimum Object
Resolution: Resolution is number of
pixels captured by the image sensor.
Higher Resolution Image
Lower Resolution Image
All cameras have a shutter between the lenses at the
front and the film at the back.
The shutter is mostly closed so that light cannot get
to the film.
When you press the button to take the photo, the
shutter opens briefly and then closes again.
The time for which the shutter is open is called the
shutter speed. The shorter the time, the less light
So, a shutter speed of 1/60th of a second
lets in half the amount of light than a speed of
1/30th of a second.
Poor focus Poor focus
Average focus Good focus
Variable Focal Length Lens or
Zoom lens has variable focal length and changes focal
length continuously without losing focusing . Typical
zoom range from 12-72mm.
Zoom Ratio 6:1 can also be expressed as 6x. The
zoom ratio can be 10x, 12x, 15x, 19x etc.
The greater the focal length, the narrower will be the
field of view and the narrower the depth of field.
Aperture is required to control the amount of light
entering the camera.
The amount of light is specified by F-number (=f/D).
The stop ring of the lens is marked with series of
numbers with a ratio of under-root of 2:
1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22
Aperture with various openings
Effect of Aperture (Iris)
Maximum to minimum distance within which the objects
remain in focus
With aperture fully opened With aperture partially open
Depth of field
Lens Aperture: Smaller the aperture or larger the
f-stop number, more the depth of field. It is because
with less aperture opening the light rays from the
outer edges of lens are cut off, narrowing the
maximum convergence angle at the focal point.
Camera to subject distance: Larger the
distance of the subject from the camera, greater is
the depth of the field
Focal length of the lens: As you increase the
focal length of the lens (i.e. narrowing it’s angle of
view), the image size increases, but the relative
depth of field decreases. Lens stop and focusing
distance remaining constant.
Factor Affecting Depth of Field
Close-up or Macro lens enables us to take photographs of the
objects closer than MOD. In Macro mode, zoom lenses cannot
Without macro With macro
A wide converter is useful for getting a large number of
people into one scene in a narrow space
A close-up lens is effective for close-up photography
of, for example, flowers and insects.
UV Filter, Skylight filter
A UV (ultraviolet) filter is nearly colorless. It absorbs short-
wavelength ultraviolet rays that the naked eyes cannot see.
Extender is mounted between the camera and the lens to
enlarge the images of the subjects, or shoot more distant