Tuesday, February 13, 2007

Basics of photography-1

A photograph is very good medium of communication. It communicates the directly. Though not as much as lingual means. It is very specific. As a part of curriculum I had Photo communication as one of my subject.
I'm jotting down some of the basics of camera for photography.
I used Nikon FM2 SLR camera with black and white film (with black and white it's easy to decide what is good. colorful means more information means more difficult).
There are mainly two settings to be looked at
  • aperture
  • shutter speed
Aperture is a small hole inside the camera through which light falls on the film. You can increase/decrease the diameter of aperture and thereby control the light falling on film.
More light means the picture will go dark (black) when developed and less light means it'll be lighter (white, see talking black and white is quite easy and direct too).
To understand the theory behind this we need to understand the chemistry part of it.
The film is layered with silver halide (a chemical), which when exposed to light form silver salts that block light or say form black portion on negative (the film after exposure). More information on this can be found at http://en.wikipedia.org/wiki/Photographic_film

There is a shutter between aperture and film which blocks the light falling on the film. When we click the camera the shutter opens momentarily let the light fall on the film and then close.
So shutter speed is the speed by which shutter opens and closes. Less the shutter speed more the shutter remains open and vice versa. So less the shutters speed more light falls on the film and darker the image. Many exciting experiments have been done by keeping low shutter speed. If you have digital camera try out fireworks mode. It has low shutter speed to capture all that sprites.

Ohhhkkk. Too much of explanation. I think only an image for this entire explanation will do.
So here it is.

More on photography to follow in later posts.

[Edit]thanks to Ami for pointing out the mistakes here. Well yes shutter speed and aperture both control the amount of light falling on the film.


AmiDA said...

from what i understand, exposure depends on both shutter speed and aperture values... if exposure is positive the image is too bright and if it is negative, it is dark... ideally the shutter speed and aperture should be adjusted so that exposure value comes to 0...

Kumar said...

oh yes!
i shud use aperture instead of exposure there.
I'll correct it.