The Exposure Triangle in Nature Photography

Exposure is the making of an image on a digital sensor by using light. Three variables go into the making of your exposure: Aperture, Shutter Speed and ISO. Changing any one of these will affect your exposure and one or both of the other two variables.

Shutter Speed is the amount of time light enters the camera to either freeze or blur motion

ISO is the light sensitivity of the sensor, which affects detail and sharpness (by adding more or less noise and grain)

Exposure is the balance between these three elements

So the exposure triangle is the relationship of the three above variables and it’s what is needed to determine an accurate exposure. Adjusting just one of the variables will result in changes to the overall exposure.

This is how it would go for us:

Let's say for example, we are photographing a herd of zebras with our 200mm f2.8 lens.

The camera states proper exposure for the current scene at f/8 is ISO 200 with a Shutter Speed of 1/125 sec.

Therefore we will have to increase another side of the triangle equally, or share the difference between the increase in the other two sides. We would then change the ISO from 200 to 1600.

But because the subjects would be moving our focus would have to be “spot-on” when focus-tracking the zebras as the DOF at f2.8 would be very shallow. So instead we rather change the ISO just 2 stops, instead of 3, and the aperture 1 stop (ISO 800 and aperture f/5.6).

This provides good DOF, low noise and a high shutter speed to capture the action.

It's all about balance - balancing the three sides of the exposure triangle to achieve your end result in terms of blurring or freezing action, making the subject pop or having more of the scene in focus and between having a sharp image or grainy image.

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