The Effects Of Changing Focal Length

When I was your age, we did not have zoom lenses, we used to zoom with our legs. Barefoot. In the snow.

So what is the effect of changing focal length vs. zooming with your legs?

Mike Browne has a great video explanation packed with examples on the impact that zooming vs walking has.

Basically it changed three things: Field of view, Depth of field and Perspective, as the vidoe so wonderfully demostrates.

Focal Length Changes 3 Things via csbphoto

  • catlett

    Your statement regarding depth of field is false and has been proved to be false over and over again. Depth of field doesn’t actually change from a wide angle lens vs a telephoto. It is a very common misconception but not true. You need to pull this video. It is spreading myths

    For proof see each of the following:

  • sam

    same thing with perspective! Perspective isn’t influenced by focal lenght! It’s just influenced by your position…

    • 432432432

      yep they should at least have a clue what they are talking about wehn they do a video.
      just look it up at wikipedia.. it´s physics.. so no wonder not one of the wannabe artist has a clue.
      changing focal length does not change perspective…

  • Bepit

    I concur that Perspective changes because position is changed in order to keep the field of view constant. It is also true that one usually does keep the FoV the same, but it should be specified that perspective only changes by changing the shooter’s position. Focal length per se does not change perspective.

    Depth of field does decrease like the square of the focal length, but now only if you keep your position fixed. At constant magnification it is independent of focal length for subject distances smaller than the hyperfocal distance. So here one should specify if you are shooting a landscape (focusing far) or a portrait (focusing close).

    So the two statements (focal length changes perspective and depth of field) cannot be true at the same time, unless you focus at the hyperfocal distance of beyond. Overall nice video, but sort of misleading.

  • Charles O. Slavens

    I’ve been a still or motion picture photog for over 40 years and I’m always pleased to see a really good explanation of basic concepts. Something we can all benefit from…. thanks.

    • 32323


  • 434343

    oh man…. perspective is changed because you change position.. utter fail this video….

  • catlett

    The thing that is annoying about this is that I understand some goof posted it on YouTube and rubes who don’t know any better like it. A site like this should not be re-posting inaccurate information. I get that whoever on this site thought the information was correct might have initially posted it but when it is thoroughly proved that the information in the video is false then the stupid video should be pulled. Photography can be confusing enough for beginners without this site spreading nonsense.

  • Byourself83

    Hmm, so his terminology is slightly off…but what I see written that is true is also too complex for a beginner to understand. This video is to show beginners the “practical” effects of lens choice or zooming.

  • Michael Turcotte

    I used to be subscribed to Mike’s channel until the completely wrong videos started. Video is a fail.