Exposure as a technical term in photography

When starting out in your photography business or even hobby you will probably need to know what this word means: "Exposure".

It took me so long to learn how to properly use it! I still can't believe how hard it was for me to understand what it means.

Knowledge about correct exposure and how to set it up in manual mode, is essential for shooting weddings. My advice is, learn how to do it right away.

A few days ago one of my friends asked me how to take nice photos of her work at an exhibition she was going to and explain to her what settings would she need to use. To explain that to her I would nearly have to teach her a beginners course in photography.

Exposure consists of three things: ISO, Shutter Speed and Aperture.

1. ISO

If we go back to the film, you would have had different film sensitivity for different lighting. If you were out on a sunny day, you would use a low sensitivity film or if you were in a dark room or at a concert high sensitivity film would be used instead. You had to buy and change that film manually.

In digital photography sensitivity of film is measured in ISO. The lower the number of the ISO the less sensitive it is. The bigger the number of the ISO the more it picks up on light. You have to remember that the


that sensitivity is, the


the quality of your photo will become. It will be covered in coloured grain, making the photograph look dirty.

To shoot outside on a Sunny to Cloudy day you will probably have to use low ISO between 100 and 500. It depends on the time of the day and the density of the clouds.

To shoot inside, in a room, your ISO will probably start from 200 and higher. This also depends on how bright the room is.

2. Shutter Speed

When you press the button on your camera you are opening it's shutter like a lid of a jar. You do that to let the light in and record it on your camera sensor.

To control for how long you want that lid open, you use the speed. That speed is measured in eg. 1/200th of a SECOND. Yes it's that quick! It opens and closes slowly eg. 1/30th of a second or quickly 1/200th of a second.

To document moving human beings I usually try not to go lower than 1/200th of a second on my shutter speed.

3. Aperture

I already spoke about Aperture and Depth Of Field in my previous post. It has everything to do with exposure. It controls the amount of light you let into your camera through your lens. Read that post for a detailed explanation of what Aperture means.

Where are all these symbols on a camera?!

Number 1600 indicates ISO.

Number 200 indicates the shutter speed at 1/200th of a second.

Number 2.0 indicates the aperture.

Symbol M on the other side of the camera means Manual Mode.

Now let's have a look at some examples:

Under exposed photographs = Not enought light!

Settings that I used:

ISO 200

Shutter Speed 1/200th of a second

Aperture 2.0

Over exposed photographs = Too much light!

Settings that I used:

ISO 1600

Shutter Speed 1/200th of a second

Aperture 2.0

Optimum Exposure for a photograph = light and dark parts of a photograph have correct amount of light. Always compare the picture to the live object that you are photographing.

Settings that I used:

ISO 640

Shutter Speed 1/20th of a second

Aperture 2.0

In this case I decided that I will keep my shutter speed constant as well as the aperture. To regulate the amount of light recorded on my camera sensors I used ISO. Obviously it was quite dark inside and I had to us quite high ISO. 

Try practicing this at home using flowers just like I did, or other objects. Keep your shutter speed constant at 1/200th or 1/250th of a second. Keep your aperture constant too, perhaps at 3.5 - 5.6 depending on your lens. The only constant that you will be varying ISO. 

Try experimenting, keeping two constants and one variable and see what happens!

... You're simply extraordinary ...