Photography, A technical review

Just take a look everywhere; everyone is capturing something or the other. Lots of photos are been uploaded daily on Facebook, Twitter etc. This is for those who want to share their work in an elegant way in photography related spaces, like Flickr or Picassa and if there is someone who is beyond that limit; reading this then please ignore my inability or lack of expertise.

To be precise, this is going to be the most boring post what so ever, full of technical terms, a typical “Gyani Guru” (A person who is apparently known as a preacher of Knowledge) kinda write up. If at any point you feel so, please bear with that.

Let us start with some basic technical term we are going to learn and use throughout this. Those parameters that define a good photo are (1) Exposure, (2) Aperture, (3) f number, (4)ISO , (5)Film Speed(Don’t be upset, film speed is necessary but film is not),(6) Shutter Speed ,(7) Guide No. etc.


Let us start with Exposure, the most important parameter. Exposure simply measures how much light is allowed to come through the lens. Higher exposure means more light. Think about a condition , u r in a room which is pitch dark, u have to open your eyes more to let more light to come in , whereas , u have to shrink your eyes when Sunshine falls on ur eyes , that means u r adjusting the exposure of your eyes for different conditions. Camera, as an optical device, works on same principle, more exposure when shooting in low light and less in daylight. The three terms that define Exposure are (1) Film Speed, (2) Shutter Speed, and (3) Aperture

Film Speed: Though films became a part of History, a glorious History actually, Film Speed is still a big issue. It defines the sensitivity of light of the Optical Sensor (CCD or CMOS or in old times Photographic Film). An Owl’s eyes are more sensitive than us, isn’t it? The good thing about Digital Cameras is, the film speed can be adjusted .The latest unit that is used is ISO (International Standard) , and in general it can be varied from ISO 80 to ISO 3200/6400/12800  depending upon the Camera. Greater ISO means more sensitive the Censor is but everything is not good with high ISO as higher sensitivity means more noise in photos. We’ll talk about Noise in later time.


Aperture : We are not doing Physics, are we? Then let us jump to the term Relative Aperture. In optics, the f-number (sometimes called focal ratiof-ratiof-stop, or relative aperture) of an Optical System is the ratio of the lens’s focal length to the diameter of the entrance pupil. So, it depends on two thing, one is focal length of the Lens and another is the Diameter of the Lens. For telephoto lenses the diameter is small whereas the focal length is greater as it is made to focus on distant objects. For wide angle lenses just the opposite. As f-number increases Aperture decreases which means it is focusing on more distant objects.



Let us define another term here, Depth of Field. Almost all of us have seen a very popular type photo; someone is holding the Sun on his or her palm. It is a hit from the very early days of photography. This phenomenon occurs as we are limited to shoot a two dimensional photo by our simple cameras, that means there is no depth of the picture. We cannot see the side view through a 2D picture but it is possible to imagine. A photo with good Depth of Field gives us an understanding that between two objects which one is nearer to me. The photo of holding Sun has a lower Depth of Field. As f-number decreases the Depth of Field increases, so, the Wide angle lenses have greater Depth of Field.

Shutter Speed: Shutter speed controls how much time the lens will be open to let the light come. In darkness we have to look on something for more time, that’s it. It is measured in second, the time span of opening the lens. As it is open for more time (higher seconds) the shutter speed actually decreases. In low light, we can shoot in higher ISO or make the Shutter Speed low to capture a good photograph. As higher ISO means more noise, so, it is better to go for lower Shutter Speed.


Ok. Now give an online exam to know how much you have learnt. Write Short notes on the technical terms related to photography.

Just kidding. What about the terms if we don’t know the typical values for a good click! Let us look at the following tables –

Shutter Speed in Different Weather Conditions for ISO 100
Cloudy Bright
Very Dull or Open Shadow
f/5.6 1/500 sec 1/200 sec 1/100 sec 1/50 sec
f/8 1/200 sec 1/100 sec 1/50 sec 1/25 sec
f/11 1/100 sec 1/50 sec 1/25 sec 1/10 sec


PS: For ISO 200 either make Aperture half of the value given in the table or make the Shutter speed double and so on.

Sujoy Datta

Sujoy is a student of Physics, currently teaching in a School in West Bengal. He loves travelling across the length and breath of the country, Quite Fascinated about Photography, music and books.

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