Chris Dickinson Photography | Stop up or Stop down, quit stopping around

Stop up or Stop down, quit stopping around

March 24, 2015  •  Leave a Comment

Perhaps you've heard the term "stop" in photography.  Used in sentences like, "I need to add a stop" or "stopping down".  This term relates to a change in illumination (adding or subtracting light) by Shutter speed or Aperture value.  When and How a "stop" is added or subtracted is a decision made by and based on the photographer's intent for a creative exposure.

For most cameras, adding or subtracting a "stop" is achieved by rolling your Main/Command Dial (on Canon/Nikon) three clicks.  Why three?  Because most cameras are calibrated to 1/3 stop increments.  So, to keep it simple, go to Av, starting at f/2.8 - rolling your Dial three clicks, brings to you f/4.0 - this is one full stop.  In between there, in 1/3 stops, you'll have 2.8, 3.2, 3.5, 4 (full stop in bold).  Using a kit lens, like the 18-55 you won't have this large (2.8) aperture.  Most likely you'll start around f/3.5 or f/5.6.  The same exercise applies though, start at f/5.6, roll your main/command dial three clicks and you'll be at f/8.0 - f/5.6, f/6.3, f/7.1, f/8.0 - in this scenario you have half as much light as f/5.6 and twice the amount of f/11.

Technical, I know!  Here's what happens to your images.  I was out the other day following along as pairs were being sorted off (cowboy terminology).  This is a great example of what happens to an exposure when you "stop" down.  Both images are right out of camera, no editing.

In this first image my settings are: ISO100, f/8.0, 1/500s @ 200mm - Looking at this image in Lightroom I haven't lost any detail in the blacks or shadows, although I could be very close with these black cows, especially on the number 11 one (it's left side).

Settings for this one: ISO100, f/8.0, 1/200s @ 200mm - In this one, I've reduced the shutter speed, 1-1/3 stops (or four clicks on my Main Dial).  Clearly we have quite a difference in illumination, in fact I've doubled the light in the frame.

As the Photographer, you get to creatively choose when and how to use these "stops". One reason I use it like this is because, in post processing, it's less destructive on an image to burn down than it is to lighten it up.  Even at ISO100, raising the exposure may produce unwanted artifacts in the image.

Happy shooting!


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