Beginner’s Corner – Exposure Modes Part 2

By Charles MacPherson–

Exposure Modes Part 2

Last month, we talked about the different exposure modes available on your camera, and after explaining the different modes, I said that I use only one mode over 90% of the time.  And I challenged you to guess which it was.

Sue Abrahamsen was the only one to get the right answer – ATTAGIRL, Sue!

Sue correctly answered that I use Aperture priority almost all the time.  She followed up by stating that I use that mode in order to control my depth of field.

She’s right, but there’s another piece to the puzzle.

I almost always shoot in A/Av mode and almost always at maximum aperture (smallest f#) because two good things happen at the same time – a real rarity in photography!

Not only to I get the shallowest possible depth-of-field as Sue mentioned, but with the lens wide open, I also get the maximum possible shutter speed.

That means that when shooting wildlife (my favorite subject), I have the best shot at defocusing the foreground and background and the best shot at eliminating motion blur.  Those are both things I want to achieve in most of my shots.

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

Notice that you’re gaze is drawn right to his face.  You look there because I defocused the background by using a wide aperture (small f#).

I just didn’t give you anything else to look at.

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

Again, for the same reason, your eye is drawn right to the goldfinch’s eye in this shot.

But there are times when I’ll change things up, depending on the circumstances.

For example, I was recently on a short Puffin Cruise out of New Harbor, Maine.  The seas were rolling at close to 4 feet, but I was determined to go after the Puffins with my 600mm.  I kept the tripod legs together, so it would act like a monopod.  That was mainly to prevent other passengers from tripping over the legs.

You can imaging what a struggle it was, trying to hold the almost 25 pounds of gear with the boat rolling so badly.  It was a real workout!

But with such a heavy load rocking so much, my main concern changed from managing depth-of-field to preventing unwanted motion blur.

I kept the ISO high to maximize shutter speed, but with the lens wide open, I risked over exposing the image – the shutter speeds were right at 1/8000th second – the camera’s maximum shutter speed.  The shutter speed flashed once in a while, indicating that even at 1/8000th second, the camera was still getting too much light.

I switched to shutter priority and set the shutter speed to 1/8000th second – plenty fast enough to freeze motion blur from the movement of the camera.  That meant that the camera would maintain that shutter speed and adjust the aperture if needed.

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

There are other times to use shutter priority too.  Any time you want to create motion blur is a great time to switch to S / Tv mode.

Glass Craftsman.  Canon 1D MkIV.  Canon 24-105mm L IS @ 67mm.
ISO 5000, f/22, 1/8th second.

In the shot above, the shutter speed of 1/8th second created the motion blur I wanted to show the movement of the craftsman moving the molten glass to the next stage of glass making.

If you still have questions about exposure modes, feel free to e-mail me and we’ll chat about it.

Next month, I’ll talk about selecting lenses.  What all the different numbers mean and how to be sure you’re picking a good quality lens that will stay with you for many years.

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Original Publication Date: November 12, 2013

Article Last updated: November 12, 2013