Focal Length / Zoom

As I continue to learn about photography, my new area of “Focus” is focal length and zoom.  My understanding so far is that there are two effects that changing the focal length will do.  First and the most obvious is the magnification of the subject area.  Bringing the subject closer by increasing the magnification.  The other effect is how the angles of light interact with the lenses.  This is the area I am trying to understand.  If there are others out there that know of good resources to this let me know.

I have found that changing the focal length can impact the amount of light that enters the lens.  This comes from indoor shots of my oldest son playing soccer.  I get good exposure when I am zoomed out, and dark exposures when I zoom in.  As a reminder, I am currently using the standard 18-55mm lens that came with my Canon Rebel T3.

I also learned that changing focal length can affect how the subject looks because of how the light is bent depending on what focal length is being used.  This is an area I will explore next week as I do a planned photo shoot of a fixed subject to see how the effects vary.

My experiment:

  • Pick an object with some details to it but that is stationary and doesn’t move.  Also set up so there is something in the background.
  • Setup on a tripod with remote shutter release.  Start with the object about 3-4 feet from the camera
  • Set a subject indoors and set the Shutter Speed, Aperature and ISO to a level that allows for proper exposure.
  • Take a photo at 18, 24,35 and 55mm focal length.
  • Import to Ipad and review the result.
  • Repeat the experiement with a few different objects.

I will update this post with what I learn.



About Troy

A Husband, Father, Lean Product Development Coach, Photographer, Musician.
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