Rethinking focal length conventions

Started 7 months ago | Discussions thread
Dennis Forum Pro • Posts: 20,433
Re: 6%

Phil A Martin wrote:

It is the focal length of the "true" standard lens, where perspective is seen as the human eye sees it. This has been an acknowledged truth throughout the history of photography and is easily demonstrated in practice.

Every lens shows the perspective of the photographer (camera). A 43mm lens produces a print that, IF viewed from a distance equal to the diagonal of the print, offers the viewer a matching FOV - you could stand in front of the original scene, hold the print in front of the scene, and it would "fit".

You can do the same with other FLs if you vary the 1/diagonal viewing distance. So that's the magic assumption - viewing distance. How often do you view photos at 1/diagonal ?

Personally, I love 40mm equivalent. I had a Minolta HiMatic with a 40/1.8. I used a 28 on APS-C for years until I switched to Nikon and haven't been excited about any of the options, so I'm living with a 35 (52mm equivalent) which I find much less useful. I think it has a pleasing, natural look, even when you don't view images at 1/diagonal, but the "matching perspective" aspect of it is mostly a mathematical curiosity.

- Dennis

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