When light falls on an object and reflected to our eyes,
we can see the object. When this light is, by proper mechanism,
directed towards the sensor of a camera or a film,
an image of the object can be recorded.
Photography is an art, it is science too. The science of photography
is related to OPTICS, a branch in physics which deals with light.
We begin to learn the technical aspects of photography, and in time,
may master some techniques of photography, at least to some extent.
But the Art of photography is different thing. It is related to how
a photographer visualises his surroundings. An ordinary person does not
see this world as a poet sees; in this way a true photographer also differs
in his/her visualisations. It is the process of developing our eyes, and
all the senses towards the happenings of this world.
Then and now
The earliest saved photographic image (Heliograph on pewter plate)
from 1826 or 1827 by Joseph Nicéphore Niépce, taken at Le Gras, France.
Source: Wikipedia
Joseph Nicéphore Niépce (French:7 March 1765 – 5 July 1833),
was a French inventor and one of the earliest pioneers of photography.
Niépce developed heliography, a technique he used to create the
world's oldest surviving product of a photographic process:
a print made from a photoengraved printing plate in 1825.
In 1826 or 1827, he used a primitive camera to produce the
oldest surviving photograph of a real-world scene.
Source: Wikipedia
Science of photography has travelled through a long way since then.
Today, the James Webb Space Telescope developed by NASA can see
objects over 13.6 billion light-years away by using infra-red technique.
The first anniversary image from NASA's James Webb Space Telescope
displays star birth like it's never been seen before,
full of detailed, impressionistic texture.
Source: https://webbtelescope.org
It is said that "A picture is worth a thousand words".
When a photograph is displayed along with a description, no doubt that the photograph
will attract us first, even before we read the description.
A true story-telling photograph is really worth a thousand
words. A description may be indecipherable, due to unknown words or language; but
a photograph may communicate feelings instantly, without any hardles of language etc.
Does the image above tell you some story?
A camera works in the same way as our eyes work. Light rays reflected
from an object travel through the lens of a camera, then bend towards
the focal point due to refractive properties of the lens. The refracted rays then
reach the sensor or film to form an image of the object flipped vertically.
There are innumerable points like
A & B which are spreading light to the sensor in
the same way as points A and B.
Light is the fundamental requirement to
make a photograph. If an object does not reflect light, it cannot be
photographed. The basic properties of an image, like brightness, contrast,
colour-saturation, colour-temparature(or white balance), tone and mood,
all rely on the quality of light present in the scenario.
Light travels through a straight line. When it hits
an object, it is reflected back. Light can also pass through transparent
objects, like a piece of glass. When light-rays pass through the lens of
a camera, they bend and meet at a point on the sensor or film. This change
of path of light happens due to the refractive property of the lens. If the rays hit
the sensor at correct point by proper focusing technique, we get a sharp
image in the form of a digital file.
Under and over exposure
In the following image, proper light has been captured, so we call
this a "properly exposed image".
But, in the following two images,
the first one is having less light than required; the second image
has more or excessive light than required. So we may call them
"under-exposed image" and
"over-exposed image" respectively.
In general, the word exposure in photography means
the overall brightness of an image, and henceforth, the term will be used frequently.
Except in some special cases, we usually want our images to be properly exposed; not
under-exposed or over-exposed. The key to shoot a properly exposed image lies in setting
a correct aperture, shutter-speed and ISO
through the buttons/menus of the camera before
we finally press the shutter.
The above three terms together may be defined as exposure triangle of photography.
An under-exposed or over-exposed image can be corrected [only to some extent] through
post-processing with photography softwares, but it is always better to use correct exposure
settings in the field itself. Also, if you shoot in raw format, the processing part
will result in a better image than shooting in jpg format.
In the next page we shall discuss
exposure triangle
which mainly consists of three important settings contributing to the overall exposure
of a photograph, namely, aperture, shutter-speed and ISO;
though the first two (aperture and shutter-speed) are directly related to gathering of
light on the sensor.
