Exposure control can pose as confusing or even intimidating when you read complicated tutorials on the subject. We try and simplify it for you here.
Exposure control is the basic technical expertise that a photographer needs to have, without which neither a technically nor a creatively perfect image is achievable. Let’s try and understand the 3 variables as simply as we can –
- Shutter Speed – Shutter speed determines the time duration for which light is allowed to enter the camera.
- Aperture – The aperture of the lens denotes the amount of light that is entering the camera and it depends on the physical diameter of the lens, and the diameter of the adjustable diaphragm within. Keep in mind, the higher the ‘f’ number or aperture setting; the smaller is the lens opening and lesser is the amount of light entering the camera.
- ISO – ISO defines the sensitivity of the sensor or film used. The higher the ISO setting, the more is the sensitivity. In other words, ISO 200 is twice as sensitive as ISO 100 and therefore requires HALF the amount of light.
To make an exposure, you need to get the right combination of the amount of light and the duration for which it is allowed to fall on the sensor. In other words… the right combination of shutter speed and aperture keeping ISO a constant for simplicity. These are the common shutter speed and aperture settings you see on your camera settings –
- Shutter speeds – 1”, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000…
- Aperture – 2.8, 4, 5.6, 8, 11, 16, 22
As you may have noticed, the shutter speed numbers double with every consecutive number, thereby reducing the time duration by 50% (the first number 1” denotes one whole second, the rest are fractions of a second). As for the aperture, every consecutive number cuts down the amount of light by half. Your camera will probably have more in-between numbers that you do not see in our list above. Our list shows you the proper ‘STOPs’ which either double or half the exposure with every ‘STEP’. Get used to the term ‘stop’; it’s going to pop up every now and then in photography articles!
So how do you know what combination of shutter speed and aperture is working out just right? Follow the in-built exposure meter of your camera! The ‘+’ , ‘0’ and ‘-‘ are indicators of the combination of shutter speed and aperture allowing too much light (+), light that is just right (0) or light that isn’t enough (-)…adjust shutter speed and aperture to get the exposure meter to ‘0’, and you are good to go! Once you have a (0) setting, try increasing the exposure by one aperture stop and compensating by reducing shutter speed by one stop to get the meter back to ‘0’! Once you get used to the idea of using multiple combinations of shutter speed and aperture, this opens up a whole set of creative possibilities…