Beginner’s Corner – Exposure Modes Part 2

By Charles MacPherson

Exposure Modes Part 2

Last month, we discussed the different exposure modes available on your camera. I also mentioned that I use one mode more than 90% of the time and challenged you to guess which one it was.

Sue Abrahamsen was the only one to get the correct answer. Well done, Sue.

She correctly identified that I primarily use aperture priority mode to control depth of field. That is true, but there is more to it.

I almost always shoot in A/Av mode at the widest aperture (smallest f-number). This approach provides two major advantages at the same time.

First, it creates the shallowest possible depth of field. Second, it allows for the fastest possible shutter speed. This combination is especially useful when photographing wildlife, where isolating the subject and minimizing motion blur are both critical.

Alaska Brown Bear. Canon 1D Mk IV. Canon 600mm f/4 L IS.
ISO 3200, f/5.6, 1/1000 second.

Notice how your attention is drawn directly to the bear’s face. The wide aperture blurs the background, eliminating distractions.

American Goldfinch. Canon 7D. Canon 600mm f/4 L IS.
ISO 320, f/4, 1/500 second.

The same principle applies here. The shallow depth of field directs your eye to the bird’s eye.

However, there are times when a different approach is necessary.

For example, I was recently on a puffin photography trip off the coast of Maine. The sea conditions were rough, and I was working with a heavy 600mm lens. My primary concern shifted from depth of field to eliminating motion blur caused by both camera movement and the rolling boat.

I increased the ISO to maintain a fast shutter speed, but even at the camera’s maximum shutter speed, the image risked overexposure. To address this, I switched to shutter priority mode and set the shutter speed to 1/8000 second, allowing the camera to adjust the aperture accordingly.

Atlantic Puffin. Canon 1D X. Canon 600mm f/4 L IS.
ISO 2000, f/5.6, 1/8000 second.

Shutter priority is also useful when you want to intentionally introduce motion blur.

Glass Craftsman. Canon 1D Mk IV. Canon 24–105mm L IS at 67mm.
ISO 5000, f/22, 1/8 second.

In this example, a slower shutter speed of 1/8 second creates motion blur, conveying the movement of the craftsman at work.

If you have questions about exposure modes, feel free to email me.

Next month, I will cover lens selection, including what the numbers mean and how to choose a lens that will serve you well for years.

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Original Publication Date: November 12, 2013

Article Last updated: May 01, 2026

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