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05-15-2018, 11:00 AM - 2 Likes   #1
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About that "normal" 50mm lens...

A fascinating article in The Atlantic entitled:
"How the 50-mm Lens Became ‘Normal’ - It’s often called the optic that best approximates human vision, but approximation is relative. An Object Lesson."

It's more of a history lesson describing why the 50mm became 'normal,' but it also reflects on other 'lenses' of perception we use. It does include a Pentax K1000 mention!

Tldr;... Here's the concluding paragraph:
Perhaps the 50-mm communicates an anxiety about whether an individual can understand someone else’s vision. Under the right circumstances, a 50-mm lens does create a perspectival relationship that, more or less, approximates the ways the majority of people see their everyday world. But it’s still relative. Mechanically, it’s relative to the specific apparatus to which the lens is attached. And metaphorically, it’s relative to all the social, emotional, or economic conditions that shape the everyday lives people inhabit. Perhaps we should be skeptical of the whole idea of a shared perspective. Rather, it is the difference between our lenses that leads to a better understanding of how machines, and people, see in the first place.


05-15-2018, 02:50 PM - 3 Likes   #2
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It's an interesting article but it misses a crucial point. A lens and camera can only be said to "replicate what the human eye sees" in the context of a print size and viewing distance.

A 50 mm lens on a 24 mm x 36 mm frame does replicate what the eye sees if printed at 12 inches by 18 inches and viewed at 25 inches (or 8x12 at about 17 inches).

No camera really replicates the human eye (a 22 mm lens in front of spherical sensor that only has high resolution in the center). In terms of total FoV, the eye is equivalent to 12 mm lens on FF. In terms of resolution, the eye is equivalent to a 400 mm telephoto lens. (And what's really happening the brain is a Brenizer tiling of that 400 mm lens)
05-15-2018, 04:05 PM - 1 Like   #3
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QuoteOriginally posted by photoptimist Quote
No camera really replicates the human eye (a 22 mm lens in front of spherical sensor that only has high resolution in the center). In terms of total FoV, the eye is equivalent to 12 mm lens on FF. In terms of resolution, the eye is equivalent to a 400 mm telephoto lens. (And what's really happening the brain is a Brenizer tiling of that 400 mm lens)
That's a great metaphor, but you neglected to mention the built-in loupe with interactive zoom, real time post-processing and simultaneous video feed, along with state of the art noise reduction and pattern recognition. The A99 is hopelessly inferior.
05-15-2018, 05:56 PM - 1 Like   #4
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QuoteOriginally posted by RGlasel Quote
That's a great metaphor, but you neglected to mention the built-in loupe with interactive zoom, real time post-processing and simultaneous video feed, along with state of the art noise reduction and pattern recognition. The A99 is hopelessly inferior.
LOL! So true!

But it's worse than you can possibly imagine because it's not like a video camera at all. When the eyeball is in motion -- and it has to move about 3 times per second to scan a scene at high resolution -- the brain is completely blind to changes in the scene. It's just like the black-out of a DSLR viewfinder. Worse, the brain retains the old false high resolution data so it is convinced that nothing is different.

05-15-2018, 06:24 PM - 1 Like   #5
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QuoteOriginally posted by photoptimist Quote
the brain retains the old false high resolution data so it is convinced that nothing is different.
What the brain "sees" is reality, everything else is an illusion. Just because your brain doesn't see what my brain sees, doesn't make my images any less realistic. Yet, we have religious wars here because the camera processors are processing.
05-15-2018, 06:49 PM   #6
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And don't forget to throw in instantaneous facial recognition features
05-15-2018, 06:53 PM   #7
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QuoteOriginally posted by RGlasel Quote
What the brain "sees" is reality, everything else is an illusion. Just because your brain doesn't see what my brain sees, doesn't make my images any less realistic. Yet, we have religious wars here because the camera processors are processing.
Indeed! Yet many a photoshopped image proves there's a difference between "realist" and "real."

It's weird to sit in an auditorium when they demonstrate the eye-blindness effect. You're looking at a scene of a parade when suddenly half the audience laughs because a guy's shirt flipped from red to blue just at the moment your eye balls happened to be moving and you did not see anything change. And then the next picture pops up of a picnic and you laugh when a picnicker disappears but the person next you doesn't see it.

And yes, we have our wars about "pure" RAW images taken with sensors in which every single pixel is blind to 2/3rds of the colors.
05-15-2018, 07:30 PM - 1 Like   #8
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QuoteOriginally posted by photoptimist Quote
human eye (a 22 mm lens in front of spherical sensor that only has high resolution in the center). In terms of total FoV, the eye is equivalent to 12 mm lens on FF. In terms of resolution, the eye is equivalent to a 400 mm telephoto lens. (And what's really happening the brain is a Brenizer tiling of that 400 mm lens)
Kind of reminds me of a DA15ltd

05-15-2018, 09:53 PM - 1 Like   #9
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I found that article quite poor.


As photoptimist rightly pointed out, any definition of what is a "normal" lens must depend on some baked-in assumptions about how the photos are most likely to be viewed. It also depends somewhat on human perception, as the scene in front of us that we pay attention to will vary depending on circumstances and subjects, but it is usually much less than the actual 180 FOV of a healthy set of eyes.



Aside from that, the conventional photographic wisdom (oddly never mentioned by the Atlantic article) says that an ideal normal lens is equal in focal length to the diameter of your film frame or sensor. That's an arbitrary rule-of-thumb, but it's one that has worked reasonably well in my experience. For 135/FF format, that would make 43mm an ideal normal lens. Guess which camera maker actually produces a 43mm lens?



Something else the article never mentioned: While 50mm became regarded as the standard normal lens for 135 format interchangeable-lens cameras (both rangefinders and SLRs), that doesn't seem to have carried over to other types and formats of cameras. For many of them the choice was 40mm (or equivalent, depending on the format).


I've become rather fond of the 40mm lens, myself. I almost never reach for the fabled "nifty fifty" if there is a 40 available instead.
05-16-2018, 12:31 AM - 2 Likes   #10
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QuoteOriginally posted by mgvh Quote
A fascinating article in The Atlantic entitled:
"How the 50-mm Lens Became ‘Normal’ - It’s often called the optic that best approximates human vision, but approximation is relative. An Object Lesson."

It's more of a history lesson describing why the 50mm became 'normal,' but it also reflects on other 'lenses' of perception we use. It does include a Pentax K1000 mention!

Tldr;... Here's the concluding paragraph:
Perhaps the 50-mm communicates an anxiety about whether an individual can understand someone else’s vision. Under the right circumstances, a 50-mm lens does create a perspectival relationship that, more or less, approximates the ways the majority of people see their everyday world. But it’s still relative. Mechanically, it’s relative to the specific apparatus to which the lens is attached. And metaphorically, it’s relative to all the social, emotional, or economic conditions that shape the everyday lives people inhabit. Perhaps we should be skeptical of the whole idea of a shared perspective. Rather, it is the difference between our lenses that leads to a better understanding of how machines, and people, see in the first place.
I also read the article and think it had some interesting points, so thanks for posting.
It wasn't everyone's cup of tea but there you are... you did a good thing by sharing it with the people on this forum. Sharing is good..!
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