Saturday, November 19, 2011

Controlling Exposure

In the previous post, we talked about understanding exposure and the settings that affect exposure. One thing they all had in common is they are all associated with light. Photography is all about light, using light. The word itself is from a combination of two Ancient Greek words: photos – “light”, and graphein – “to draw/write”. Thus, photography is literally “drawing with light”.

Film Strip With Pictures - Image: Anusorn P nachol /

The combination of the three settings Shutter speed, Aperture, and ISO controls exposure. The combination can drastically affect the outcome of a photograph. You should set these combinations by priority. For example: In a sunny day situation, you want to take a photo of a person with the background completely blurred. First select your proper ISO; since it is sunny the ISO should be set to the lowest setting. I believe this should be set first because the current available light will not change drastically during a photo shoot. Next thing you should do is set your priority between shutter speed and aperture. In this situation, let's say you want the background to be completely blurred; aperture should be your higher priority over shutter speed. If you want a blurred or bokeh background, the lowest aperture value preferably f1.8 or lower should be selected (If you can’t set your aperture to f1.8 then you might be limited by the type of lens that you use, learn more about camera lens type). Now, shutter speed will be used to compensate for the increased amount of light. Since we allowed more light by selecting a wider aperture, shutter speed should be increased to reduce the amount of light that passes through. If the combination is right, the camera should reward you with a beautiful photo with proper exposure.

Pink Flowers - Image: Graeme Weatherston /

This shot was taken with the idea of blurred background. Thus the aperture is the priority over shutter speed. Shutter speed was used to compensate for the increased amount of light.

Grand Central Subway Train Station - Image: Paul Martin Eldridge /

The idea of this shot was to capture the movement of the people, to make the photo appear as though the train station is busy. For this image shutter speed is the priority aperture. Aperture was used to compensate for the increased or decreased amount of light.

Using Give and Take Rule to Control Exposure

Practice controlling exposure by playing with two settings first; mainly shutter speed and aperture. Try giving a stop­ higher to shutter speed then take the lost light in aperture by moving a stop lower. Use the one stop chart below as a guide.

One stop chart - click to zoom

Master the give and take rule, by using shutter speed and aperture first, then try using three settings; shutter speed, aperture and ISO. Check your meter for proper exposure. Keep practicing!

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