Focal length/perspective at which you see the world

Started May 5, 2014 | Discussions thread
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Jonathan Brady
Jonathan Brady Veteran Member • Posts: 5,882
Focal length/perspective at which you see the world

I've seen many people refer to 35mm and 50mm as the most "natural perspective" with occasional vehement arguing as to which is more natural when framing a shot. I've been trying to kind of wrap my head around this a little bit.

My assumption is that when they hold a camera up to their eye to frame a shot, if they kept both eyes open - one looking through the viewfinder and the other viewing the world around them - that the view through both eyes would be the same. Is that right?

I tried this out by mounting my 15-85mm lens on my 70D, sitting in my chair and focusing both eyes on a box on the counter. I held the camera up to my right eye and kept both eyes open and simply zoomed until the box was the same size to both eyes. Once I thought it was about right, I began alternately opening and closing my eyes to ensure it was dead on and I fine tuned. Then I double checked to see if everything outside the frame was lining up. For instance, it just so happened that there was a load bearing wall about 15" wide on the left side of the frame of the camera view. Where the view from the camera stopped, my left eye picked up immediately. The same was true on the right side but with a different object.

Then I looked at the lens to see where the zoom landed. It was around 50mm. I snapped a pic and checked out the exif and it said 50.0mm.

So, my questions are:

  • Does the 1.6x crop factor apply? Is my natural perspective basically 80mm? Or is this a case of "a 50mm lens is still a 50mm lens just with part of the image cropped out"? I suspect it's the latter, and not the former.
  • Also, does the .95x magnification of the viewfinder play a role? (I assume it does, but not by a huge amount)
  • What about the 98% coverage viewfinder? Does that change anything? (I assume it does, just a little though)
  • Re: the above two bullet points - I switched to LiveView on the back panel and it changed very minimally (almost imperceptible)
  • Does my vision have anything to do with this? I ask because I have 20/15 vision (possibly slightly better). I don't believe it does - I think 20/15 basically means I have Otus eyes vs L-series eyes - lol (which might explain my constant quest for high quality glass! lol)

Any assistance would be greatly appreciated!


 Jonathan Brady's gear list:Jonathan Brady's gear list
Sony a9 Sony Alpha a7R III Sony FE 55mm F1.8 Sony FE 35mm F1.4 Zeiss Batis 25mm F2 +5 more
Canon EOS 70D
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