Topic: Lenses' and human eyes' field of view

[hookstrapped]

Using Ken Rockwell as a source (closest thing to God I could find), I wanted to confirm my impression that the horizontal field of view of a 40mm lens landscape is about the same as the width of a vertically oriented 21mm lens. The respective (or vice versa, I can't remember) field of view angles are 58 and 56 degrees. And according to this interesting (first one!) petapixel piece, the human eye's central field of vision, not counting peripheral vision, is about 55 degrees, so yeah, 40mm more or less.
http://petapixel.com/2012/11/17/the-camera-versus-the-human-eye/

The long side field of view on the 21mm is 80 degrees, which makes sense with that second pic of my set http://www.filmwasters.com/forum/index.php?topic=7500.0 of the women walking on the sidewalk in the bottom of the frame and the overhead ceiling at the top of the frame. This is beyond the human eyes' vertical field of view, therefore it's a bit trippy. I guess the shots with more distant subjects don't seem so trippy because that extra vertical field of view is occupied by an extended view of sky and ground, so it doesn't appear odd like seeing something in front of you and above your head at the same time.

[Indofunk]

I've always maintained that the 40mm perspective of my Canonet was as close to "normal human vision" as I'd ever seen through a lens. Thanks for confirming this via MATH (and, of course, PetaPixel and Ken Rockwell, both of whom I worship as demigods).

[hookstrapped]

Did you know that Ken Rockwell has a growing family, and that he has to keep getting wider angle lenses to take pictures of them?  That's where the cost comes in.

[Indofunk]

MATHematically, his family can grow at the rate of one human every 9 months. Until, of course, one of his progeny reaches reproductive age, at which point his family can grow at the rate of two humans every 9 months. And an extra human per 9 months each 9 month period after that.

We'd better donate a LOT of money to him, right now....

[Pete_R]

Using Ken Rockwell as a source (closest thing to God I could find), I wanted to confirm my impression that the horizontal field of view of a 40mm lens landscape is about the same as the width of a vertically oriented 21mm lens. The respective (or vice versa, I can't remember) field of view angles are 58 and 56 degrees.

The two angles are actually 48 (40mm lens with 36mm neg width) and 59 (21mm lens with 24mm neg width) so not that close really. I have a spreadsheet that does the calculation for you (same calculation that Ken Rockwell shows). You can download it from www.z0g.eu/aov.xls

[Pete_R]

I've always maintained that the 40mm perspective of my Canonet was as close to "normal human vision" as I'd ever seen through a lens. Thanks for confirming this via MATH (and, of course, PetaPixel and Ken Rockwell, both of whom I worship as demigods).

If 55 degrees is normal vision then a 35mm lens is pretty much spot on.


Edit:

Thought I'd add my own take on this.

A quick search will tell you there is widely varying opinions on what is the angle of view of the human eye so trying to match a lens to the angle of view is never going to be easy, if at all possible. A better approach is to find the lens that gives an image that is, proprtionally, the same as a viewer would see if they were looking at the original scene. A viewer holding a print of a certain size at a certain distance away from their eyes will be creating a certain angle of view (of the print). Of course, we can't control the distance at which a viewer views a print but, generally, a larger print will be viewed from further away and a smaller print from closer to. So the angle of view will remain similar. The type of subject will cause differences - an image with a lot of detail, say a group of faces, will usually get viewed closer to than say a landscape. So it's up to the photographer to decide what's appropriate for them, their images and the way they are viewed. But if you can define that then it's easy to come up with an angle of view and find the lens that matches it.

[02Pilot]

None of these FOV calculations take into account my ability to swivel my head 360 degrees or the third eye that occasionally appears in the middle of my forehead....

Hmmm, perhaps I've said too much. But now that I have, y'all'd best be thinking about throwing some money at me instead of this Ken Rockwell character. No doubt.

[Pete_R]

None of these FOV calculations take into account my ability to swivel my head 360 degrees or the third eye that occasionally appears in the middle of my forehead....

Hmmm, perhaps I've said too much. But now that I have, y'all'd best be thinking about throwing some money at me instead of this Ken Rockwell character. No doubt.

With that third eye of yours you should have known, even before you asked, that you ain't got a snowflake-in-hells chance of us sending you any money. On the other hand, I think you should add a Lomo Spinner to your Xmas list.

[jojonas~]

None of these FOV calculations take into account my ability to swivel my head 360 degrees or the third eye that occasionally appears in the middle of my forehead....

Hmmm, perhaps I've said too much. But now that I have, y'all'd best be thinking about throwing some money at me instead of this Ken Rockwell character. No doubt.

you need to photograph with this then!

[hookstrapped]

Using Ken Rockwell as a source (closest thing to God I could find), I wanted to confirm my impression that the horizontal field of view of a 40mm lens landscape is about the same as the width of a vertically oriented 21mm lens. The respective (or vice versa, I can't remember) field of view angles are 58 and 56 degrees.

The two angles are actually 48 (40mm lens with 36mm neg width) and 59 (21mm lens with 24mm neg width) so not that close really. I have a spreadsheet that does the calculation for you (same calculation that Ken Rockwell shows). You can download it from www.z0g.eu/aov.xls

Ahh, Looking at this http://www.tawbaware.com/maxlyons/calc.htm I think I took Ken's 40mm angle of 56 degrees as the horizontal value when it's actually the diagonal value.  So the 21mm vertical oriented width is actually more comparable to a 35mm landscape oriented width. 

[Late Developer]

I don't think I've ever owned or used a 40mm lens (in 35mm format) but picking up and looking through the viewfinder of a camera with a 35mm lens on the front has always seemed pretty much how the world looks to my spectacle-adjusted, long-sighted eyes.

[charles binns]

My wife's eyes have the amazing ability to switch from 12mm ultra wide angle to 300mm whenever it suits her.  She also has these amazing filters in her cornea which seem to block out anything she doesn't want to see. 

Add to that a memory which seems to be able to twist the passage of time to change past events as she sees fit and you've got one hell of a camera/video recorder on two legs.

I wonder if mankind will ever be able to produce a camera with such magical properties.

[k.hendrik]

My wife's eyes have the amazing ability to switch from 12mm ultra wide angle to 300mm whenever it suits her.  She also has these amazing filters in her cornea which seem to block out anything she doesn't want to see. 

Add to that a memory which seems to be able to twist the passage of time to change past events as she sees fit and you've got one hell of a camera/video recorder on two legs.

I wonder if mankind will ever be able to produce a camera with such magical properties.

I know that woman !!

[Francois]

Lets not forger that we see a sharp image only in the center region of the eye.
We also only see the center field in color as the rest of the eye is populated only by rods.
Exposure also affects the color range we see as the cones are not very sensitive when compared to rods.

[Indofunk]

One of the greatest Wiki-holes I ever found myself in was the whole rod-cone thing. That's how I first found out about the Purkinje effect

[Pete_R]

Anyone want to check my angle of view. Here's the back of my left eye.

(And if there's any optoms out there, I'm aware of the white-without-pressure in the bottom right. I'm keeping an eye on it - so to speak).

[Offertonhatter]

I don't think I've ever owned or used a 40mm lens (in 35mm format) but picking up and looking through the viewfinder of a camera with a 35mm lens on the front has always seemed pretty much how the world looks to my spectacle-adjusted, long-sighted eyes.

I do have a 40mm Lens. My Pancake Pentax DA, and it works brilliantly on film SLR's. Pretty damn close to standard viewing area is the diagonal of the film frame (about 43.2mm)
Mind you, Pentax did (still do) a 43mm F1.9 Limited. Now THAT is a lens I want to add to my collection. :-)

[Adam Doe]

MATHematically, his family can grow at the rate of one human every 9 months. Until, of course, one of his progeny reaches reproductive age, at which point his family can grow at the rate of two humans every 9 months. And an extra human per 9 months each 9 month period after that.

We'd better donate a LOT of money to him, right now....

You're forgetting the possibility of twins, triplets, etc.

[timor]

MATHematically, his family can grow at the rate of one human every 9 months.

Once more mathematics are failing us. Woman body needs at least 50 days to restart the reproductive cycle. But then Super Rockwell probably married super woman.  Then come multiplets. 

[Benjamin Broad]

This is an interesting idea.

I measured the focal length of my eyes by comparing a scene while looking through a zoom lens. I held a 35mm format camera to my face in portrait mode and adjusted the zoom until the image through the lens matched what my other eye saw. For me it is about 64mm. I tried to work out what that would be in degrees, but the math is beyond me.

I guess it will be different for everybody. And I wonder if we all see the same colour - my wife suggests that my colour-vision differs from hers. I had a shirt that she saw as grey, but I saw as grey-green. We have many more examples and we both work in the arts and so are colour-literate. I have also heard about women who have an extra cone in their eyes sensitive to orange giving them RGBO vision (Tetrachromacy).


Ben.

[Francois]

There's quite a few things relating to perception. There's the eye and then there's the part that does the interpretation, namely the brain.
We used to have a member (OriginalAnn) who has synesthesia. Her world is definitely more colorful than ours.

[Pete_R]

I measured the focal length of my eyes by comparing a scene while looking through a zoom lens. I held a 35mm format camera to my face in portrait mode and adjusted the zoom until the image through the lens matched what my other eye saw. For me it is about 64mm. I tried to work out what that would be in degrees, but the math is beyond me.

Problem there is the viewfinder magnification will affect the result so it's not really valid. If you think about it, the focal length is the distance from the lens to the point of focus (the back of the eye) so if your fl is 64mm you have some huge eyes. The focal length of the human eye is generally thought to be about 22mm but it depends who you believe. Some say 17mm. Try this page... http://hypertextbook.com/facts/2002/JuliaKhutoretskaya.shtml

[Francois]

But the field of view depends on the size of the area exposed.

Best way to figure it out would be to devise a jig where the eye is forced to look forward and a moving target slowly gets moved to the side until it disappears from sight while still fixating the infinity target. Then you measure the eye to external target angle. Since both eyes are different, you repeat for the other eye and add both values to get the full vision angle. Then, you take a small program I just got from the Android store called "CamCalc Free" and try various focal lengths for the film format you want.

[Sandeha Lynch]

No comment to make on the science, but if I ever get down to just one lens it will be my Pentax 43mm Limited, if not the 31mm.

[Benjamin Broad]

Problem there is the viewfinder magnification will affect the result so it's not really valid. If you think about it, the focal length is the distance from the lens to the point of focus (the back of the eye) so if your fl is 64mm you have some huge eyes. The focal length of the human eye is generally thought to be about 22mm but it depends who you believe.

mmm...

Ok, so the eye has a focal length of 17mm, and a corresponding angle of view (~120º or something). When we look through another lens we are subjected to its length and angle of view in addition to ours, and this is cropped and magnified by the view finder (the magnification may be only 1 or 2 percent). All of this combined creates a scene that within the frame of the viewfinder overlays well with the image taking a direct path to the other eye, thereby creating an apparent focal length of 64mm if we discard the angle of view as a criterion.

Or, is focal length the incorrect term used to describe this effect? Should it really be magnification of the image within the cropped area of the viewfinder?

Ben.

[Francois]

I don't think that the focal length in this case is much information since our eyeballs are not the same size as any regular film formats.

[mcduff]

Whatever the focal length of the eye is, is only relevant when correlated to its sensor size. Its complex to compare due to peripheral view, the uneven distribution of rods and comes, that there are two of them that we are combining the image from, and the fact that the bloody things are always moving and scanning.

I was taught to keep both eyes open when shootjng. I do know when I am using a 50mm (or equiv on diff sized films or sensors) that the image and proportions that both my eyes see seems most similar when compared to modest wide or tele lenses. But I think it is showing a narrower field of view which I think would be akin to a modest (35mm?) wide angle.

[Benjamin Broad]

I just found a nice article on human colour vision over at the Luminous Landscape:

http://www.luminous-landscape.com/essays/observing_and_managing_color_dealing_with_color_vision_anomalies.shtml

Ben.

[gothamtomato]

Years ago I was told that a 35mm lens (on a 35mm camera) was the closest to a human's field of vision - and I think it is interesting, the photographers whose reportage work is done consistently with 35mm lenses (or the equivilent). Two of my faves being Mary Ellen Mark and Annie Liebovitz.

[Indofunk]

I just found a nice article on human colour vision over at the Luminous Landscape:

http://www.luminous-landscape.com/essays/observing_and_managing_color_dealing_with_color_vision_anomalies.shtml

Ben.

Thank you for that! It was fascinating, and I love how they got all sciencey about it Particularly, I didn't know about the two variations of the "red" (L) opsin gene that together can cause tetrachromacy in women. I always thought that tetrachromacy was the result of having a "damaged" opsin gene from your (colorblind) father. Or, I suppose, tetrachromat mother

Also, this statement:

Color is not a topic in physics.  Pure, monochromatic, light is characterized by its intensity and wavelength.  The combination of pure light from two different sources simply gives a light mixture with two different wavelengths.

Obvious, but mind-blowing

[johnha]

I do have a 40mm Lens. My Pancake Pentax DA, and it works brilliantly on film SLR's. Pretty damn close to standard viewing area is the diagonal of the film frame (about 43.2mm)
Mind you, Pentax did (still do) a 43mm F1.9 Limited. Now THAT is a lens I want to add to my collection. :-)

I used to prefer my Pentax M40/2.8 pancake until I bought the Pentax 43mm - I haven't used a 50mm lens since.

John.

[hookstrapped]

I just found a nice article on human colour vision over at the Luminous Landscape:

http://www.luminous-landscape.com/essays/observing_and_managing_color_dealing_with_color_vision_anomalies.shtml

Ben.

Thank you for that! It was fascinating, and I love how they got all sciencey about it Particularly, I didn't know about the two variations of the "red" (L) opsin gene that together can cause tetrachromacy in women. I always thought that tetrachromacy was the result of having a "damaged" opsin gene from your (colorblind) father. Or, I suppose, tetrachromat mother

Yes, thank you for the link. I knew that men are more likely to be colorblind, though I didn't know why until I read that piece.  But the thing that really caught my attention was that some women not only have the standard RGB sensitive cones, but cones sensitive to a fourth color. I've been teased a lot, by countless women, about how I describe the colors of certain things, and for a while I thought it was just I didn't have the vocabulary.  If something was sort of redddish, I called it red. But then I started suspecting there might be more to it then that, that I actually didn't see some of the differences that women see.  And I was thinking of what's really en vogue these days in color photography in regard to color palette, and it's this low contrast desaturated color palette with little range over the color spectrum, and I basically don't like it.  I think for the most part it looks all the same and is kind of boring.  And it seems most of the photographers are women. Now I'm thinking I'm just not seeing all the nuance and detail that the photographers see.  My use of color is kind of over the top and now I'm thinking it has to be because I don't see the point otherwise. I literally don't see why you would use color otherwise, maybe because I'm blind to more subtle aspects of color.

[mcduff]

I've been teased a lot, by countless women, about how I describe the colors of certain things, and for a while I thought it was just I didn't have the vocabulary.

My wife and have this go on all the time. There are a few colours (khaki is one) that we always disagree on. One of us will call something brown when the other set of eyes looks at it as green. It confuses me so much that I can't even remember which one of us see things on the green side. There are a few other break points in the colour wheel that our eyes see REALLY differently. And to be clear my wife is a visually sophisticated person.

 And to be clear this is not a "That is not 'persimmon' it is 'morning dawn'" type discussion in the paint store. This is a "can you grab the bag on the green chair" type comment that they other does not have a bloody clue as to what it means. We find it pretty funny. Glad to hear we are not alone 

[Bryan]

This reminds me of something that happened at a dinner party with my parents and mother inlaw.  My wife made a dish out of purple potatoes, they clearly looked purple to my wife and I but to our parents they looked green.  All three of them swore up and down that the potatoes were green.  Makes me think age affects the colors you see as well.