The Largest Lens Opening Allows The Fastest Shutter Speed

As you may know, there are motion filled opportunities everywhere–and that in capturing them you find yourself on either end of the shutter speed spectrum, using either fast shutter speeds to freeze the action in crisp, sharp detail or slow shutter speeds to blur or imply the motion that was there.

There’s rarely a middle ground when it comes to the moving world, and with that in mind, it won’t be long before you discover that most of your action (and also low-light) photography time is spent anywhere between 1/500 and 1/1000 sec. or between 1/4 sec. to 8 seconds.

Valuable Lesson

(1) You will always attain the fastest possible shutter speed at any given ISO when you us the largest possible lens opening (aperture).

(2) You will be able to attain the slowest possible shutter speed at any given ISO by using the smallest possible lens opening.

This is one of the best lessons I know when it comes to action photography and one that will lead you further into the world or creatively correct motion-filled exposures.

To practice this concept do the following: Choose a moving subject, such as a waterfall, a child on a swing, or something as simple as someone pounding a nail into a piece of wood. Set your camera to Aperture Priority mode and your ISO to 100 (or 200 if that’s the lowest your camera offers); then set your aperture wide open (f/2.8, f/3.5 or f/4) and take an image of the action before you. You have just recorded an exposure at the fastest possible shutter speed based on the ISO in use, the light falling on your subject, and, of course, your use of the largest possible lens opening.

Now stop the lens down 1 full stop. So, if you started at an aperture of f/2.8, go to f/4; if your lens starts at f/4, go to f/5.6. Then, once again, make another exposure. Do this over and over again, each time with the aperture set to f/8, then f/11, then f/16, and finally f/22. Each time you change the aperture by a full stop, your camera does a quick recalculation and offers up the “new” shutter speed to maintain a correct exposure. And since you’re stopping the lens down with each full-stop change in aperture (making the hole in the lens half as big as it was before), your shutter speed has now doubled in time to complete–or, in other words, your shutter speed is becoming progressively slower. The slower your shutter speed, the more likely that the resulting image will exhibit some blurring effects, since the shutter speed is too slow to freeze the action.

And what about waterfall shots you may be asking? That well-known cotton candy effect you get with the water doesn’t start until you us apertures of f/16 or f/22. Likewise, isn’t that motion-filled image of your child on the swing really something? Note how the faster shutter speeds freeze your child in midair but the slower shutter speeds turn your child into a ghots. Take notes on your exposures and make the discovery as to which combination of aperture and shutter speed resulted in the most creatively correct photographic exposure.


So to sum this up in the easiest possible way to understand, if you are going to take pictures of a waterfall, use a tripod or set your camera down on a rock. Set your f-stop to f/16 or f/22 and your shutter speed to 15 – 30 seconds. The waterfall will freeze in midair but still look like its moving in your picture.

If you want to take pictures of action and have the subject as crisp as you can, set the f-stop to f/1.4 or f/4 and your shutter speed to 1/1000 of a second. You will stop time for that split second. Also, you con convey the same sense of movement by using the tip above, slow shutter speed and high f-stop will make your subject blurry and the background show movement.

If you would like to know more about photography let me know in the comments. Also, feel free to ask any question you might have. Look forward to hearing from you.

One Comment

  1. The BAD part about having the lens wide open, is that the depth of field is VERY tight…so for instance if the camera is focused on the leading shoulder of a football player coming at the camera, his face might be out of focus. I tend to try and shoot a few stops up to increase that depth of field but still have a fast enough shutter speed to capture most action(1/500th is decent to catch most action, 1/250th if you are lucky, super fast paced things like golf swings need 1/1000th, or as high as 1/4000th). This takes practice to get great results so get out and practice!

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