What’s the deal with 50mm?

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  • #214750
    ravikantrai
    Participant

      I have read a lot of talk about 50mm lens being normal. I know Dave pointed out Yasujiro Ozu who used that focal length a lot. Hitchcock has too. I’ve seen it described often as “normal” lens in photography discussions but can’t recollect why is it considered normal. It “feels” normal when I look at something from a 50mm lens and then look at that same scene with my eyes. But I can’t put a finger on why that is “normal” vision.

      Would you use 50mm, or rather, have there been instances where you you’ve reached for 50mm as a focal length more than 40 or 35 or anything on the wide end of the spectrum?

    Viewing 7 replies - 1 through 7 (of 7 total)
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    • #214751
      dmullenasc
      Participant

        It’s a loaded topic. The truth is that 50mm is considered “normal” in view for the 35mm still format (8-perf 35mm) which is more like a 35mm in 4-perf 35mm cine. But the 50mm was the most common lens made for early cinema cameras so most silent era movies were shot on it and built their sets to accommodate that view, meaning they had room to back up the camera to hold actors head to toe. So 50mm became the “normal” lens for cinematography too (which predates the 35mm still camera format) but is actually a bit on the long side in 4-perf 35mm.

        But also remember silent movies were shot Full Aperture, the 50mm looked slightly tighter on the 1.37 Academy sound format and even tighter when that was cropped vertically to 1.85 in the 1950s, at which point filmmakers who were used to the 50mm view in Academy started to use a 40mm (or even 35mm) to compensate.

        I don’t know why the first lens made for cinema cameras was a 50mm, whether that was the easiest to design or because it was considered “normal”, who knows. I wouldn’t think too much about whether a lens is “normal” or not.

        #214756
        ravikantrai
        Participant

          Thank you Dave, that’s really helpful and informative. It’s interesting that entire sets were built around something like a “normal” lens!

          #214757
          Roger Deakins
          Keymaster

            I’m not someone who dwells too long on the question of what might be considered normal. However, if you look through a 35mm still camera and compare that image with what you see through your other eye, you can judge for yourself what appears to be ‘normal’.

            #214758
            dmullenasc
            Participant

              Roger, the “Ur-Leica” by Barnack dates back to 1914 — that and other early 35mm still cameras were all horizontal movements around 36mm x 24mm and started with a 50mm lens.

              But the 4-perf 35mm cinema camera predates those and it also used a 50mm!

              So there must have been a reason why 50mm was used in both systems despite the different fields of view. Was it easier to design and build at a reasonable f-stop? Was it harder to make a 35mm focal length back then with the restriction on number of elements due to light transmission loss that was undistorted on the edges? Larger still camera formats like 4×5 and 8×10 that were in use in the 1800s used longer lenses.

              #214762
              Roger Deakins
              Keymaster

                Right! Interesting! Perhaps it was simply that the 50mm was easier to make. But for the movies wasn’t it also about projection? The viewer in the premium seat and their field of view being in sync with the camera on the set. I thought I read somewhere.

                • This reply was modified 10 months, 2 weeks ago by Roger Deakins.
                #214769
                Stip
                Participant

                  It seems like 50mm was – and still is – the easiest (and cheapest) to design and build to achieve good image quality at fast apertures.

                  The ‘Double Gauss’ design was invented in 1817 by Carl Friedrich Gauss as a telescope lens and later refined by many others like Taylor Hobson in the 1920’s (later resulting in the Speed Panchros). The current design, presently found in inexpensive but high quality fast lenses like Canon EF 50mm 1.8 or Nikon AD 50mm 1.8, can be traced back to 1895 to Paul Rudolph and Carl Zeiss (the first Zeiss Planar lens).

                  From Wikipedia:

                  “The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to f/1.4 with a wide field of view, and has sometimes been made at f/1.0. The design appears in other applications where a simple fast normal lens is required (~53° diagonal) such as in projectors.”

                   

                  So the projection thing would make sense not just for the viewer experience but also on a technical level!

                  #214774
                  ravikantrai
                  Participant

                    That is so interesting! I was initially reluctant to post this topic haha. Because I know what’s normal or not is not a basis of any creative decision with cinematography but I was just curious about the “why” and the history of it.

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