OldBobD Loc: Ohio

I think I read somewhere that early SLRs (Contax?) required more space for mirror swing than current 43mm lenses would provide. 50mm worked and thus became the "standard".

blackest Loc: Ireland

How lucky would that be for a relatively arbitrary measuring system to come up with a nice round number like 50mm why not 43mm?
with range finders you could go a bit shorter and they often did.

I'm not saying 50mm isn't pretty close but a little wider is probably closer still and it is harder to make a lens shorter than the registration distance.

https://www.howtogeek.com/309816/what-is-a-normal-camera-lens/

On a full-frame camera, a normal lens is considered to have a focal length of 50mm. This was set by the creator of the Leica camera system, Oskar Barnack, pretty much arbitrarily. In reality, any lens with a focal length of between about 40mm and 58mm will look roughly like how things appear to your eyes.

(link removed)
this essentially says normal is equivalent to the sensor diagonal which for 35mm is 43.27mm and gets rounded to 50-55mm

For the eye ~22mm
http://www.clarkvision.com/imagedetail/eye-resolution.html

interesting page the iso of the eye is interesting about 800 iso in the dark and around 1 in daylight.

https://hypertextbook.com/facts/2002/JuliaKhutoretskaya.shtml

"What is the focal length of the eye? I did a google search and found many "answers" ranging from 17mm to 50mm (50 is totally absurd). For the correct answer, is Reference: Light, Color and Vision, Hunt et al., Chapman and Hall, Ltd, London, 1968, page 49 for 'standard European adult'":
Object focal length of the eye = 16.7 mm
Image focal length of the eye = 22.3 mm
The object focal length is for rays coming OUT OF THE EYE. But for an image on the retina, the image focal length is what one wants….
So this explains the commonly cited ~17mm focal length, but the correct value is ~22 mm focal length."

I may be way off base, but that doesn't make you correct either. Seems fair with the normal as far as a negative is concerned being 43.27 that rounding to 50mm makes for a relatively simple lens for a dslr with its registration distance and why other systems used 45mm...

ken_stern Loc: Yorba Linda, Ca

TRUST ME
I feel your frustration -- If you page back to Pg 13 you will see my failed attempt to explain what I was taught so many years ago while sitting in a Photography Class or was it when I 1st read my Kodak Lens book sometime during the last century -- I'm sure if either of us had the time or courage and paged back we would may even find others that also attempted & failed
However you got to give these guys credit ---
They have gone ahead & invented a whole new branch of pseudo-inquiry called BOZO PHOTOGRAPHY SCIENCE !!!

mcveed Loc: Kelowna, British Columbia (between trips)

Here is a direct quote from page 23 of the Kodak Workshop Series "Lenses for 35mm Photography" by Artur Landt published in 1993 in Germany and in 1998 in USA. "Designating a certain lens as a normal, telephoto or wide-angle is always done in reference to the diagonal of the film format in question.....In the 35mm format focal lengths of 35mm or less are considered wide-angle, while those over 70mm are recognized as telephoto." What he doesn't say is why the diagonal of the film format was taken as the 'normal' lens. The reason is because of the optical phenomenon I described above.

JohnSwanda Loc: San Francisco

Just because you remember something you were taught or read many years ago doesn't necessarily mean it was correct.

BartHx

"interesting page the iso of the eye is interesting about 800 iso in the dark and around 1 in daylight."

This is because the sensitivity of the eye varies according to how much visual purple has been deposited in the retina. That is a pigment that gradually develops in the retina and increases sensitivity when the eye needs additional sensitivity to report an image. It can take up to twenty minutes or so to reach maximum effect and can be destroyed by an extremely short flash of white light. Navigating a boat at night away from ambient light from the shore, headlights are useless. However, after the development of visual purple, you can clearly see where you are going. However, a very brief flash of white light can effectively blind you for a period of time while the visual purple is being replaced. Interestingly, your night vision is not significantly impacted by red light. That will allow you to have illumination where you need it (for example on your instrumentation) without damaging your night vision.

jimpitt

So Kodak preaches a long time ago that in film 35mm - 70mm is "normal." That's 52.5 mm in the middle folks. This whole banter started with discussion identifying roughly 43 mm to 58 mm, slightly narrower than the Kodak infor. 53.5 mm is what I suggested as being the normal human eye. Nikon preached 50, Minolta 55. Sounds to me like we are right back where we started with a whole lot of wild conjecture in the middle of this blog. It seems normal is 35-50, and we can argue all day about where on that line is the "real" normal. My 16-35 (24-52) is considered semi-wide, and my 28-300 (42-400) is normal and semi-telephoto which is all I wanted comment about. I appreciate all the extra highly technical information, although I do not understand most of it. Thanks for the entertainment.

pendennis

The image circle on a given lens is based on the total design of the lens, mostly the lens element diameters, not the focal length. A wide angle lens on a 4x5 camera (e.g. 90mm) allows coverage of the format with some swings and tilts. Likewise, a 45mm lens on a 645 camera covers the 6x4.5 format.

The wider the lens element, the more costly it is to make. An example would be the 6.5mm fish eye lenses. There's a reason why they cost $5-$6K even in the 80's. Also note that 85mm f1.4's, 500mm f4's, etc. are expensive mostly because of the size of the elements relative to more "normal" focal lengths and speeds.

rehess Loc: South Bend, Indiana, USA

I have noticed when using my 35mm film camera lately, that I'm using wide angle more than I used to. I have a feeling that labeling the 50mm lens as "standard" made me unconsciously think "you should be using this lens more than any other", and sometimes I forced the perspective to make it work when I should have done what I learned once I had a zoom standard lens - to go wider when I have problems making it work.

therwol Loc: USA

I use a Nikon D810. I have a 24-120 VR, older 28-105 D, 80-200 F/4 VR, and a several primes ranging from 24mm to 50mm. I get the sharpest pictures with the 50, but I've almost abandoned it. I tend to take most of my pictures at the wider end and longer end of what I have. If I don't want to lug around one of the zooms (the 28-105 isn't terribly heavy, but it isn't the best of my lenses) I'll stick a 24mm or 35mm prime on the camera, especially if the pictures are going to be taken indoors. I think that 50mm is just a bit too long for what I like to take pictures of. If I want something longer, then the 80-200 goes with me. I could sometimes use something longer, but I wouldn't want to lug it around.

This discussion has been somewhat technical and irrelevant to me. I know what I like to use from experience, and that's what matters to me.

wizbird Loc: Burnt Store Marina, Punta Gorda, Fl

In reviewing the post I now see that he is talking about a film camera; not a cropped camera. Before digital cameras news paper photographers used 35mm lenses as their standard lens. It was felt that they more closely related to what the eye saw. That's why you are using a wide angle lens. My everyday lens on my Micro 4rds is a 20mm. This would be 40mm on a film camera. On my DSLR, with a zoom to get close to a 35m (Film) I would set it for about 24mm.

pendennis

Have to disagree about photojournalists' lenses. Most of the news photographers I knew in the 60's-to-80's era, split their usage between the 50mm f1.4, and a 105mm f2.5. They, by and large, needed shutter speed, not depth of field. They pushed Tri-X as much as two stops (sometimes more), in order to stop the action. One of the photographers I knew at the Courier Journal, used a 105mm f2.5 on his F2. He always believed that being in too close could ruin the spontaneity of the moment.

By the 1960's news photographers were abandoning the Speed Graphic in droves, and going to 35mm. The Speed Graphic was slow, bulky, and flash was needed to illuminate the scene. The 35mm camera lightened the load considerably. They could carry two cameras and lenses, and a lot of film for less weight than the 4x5. At the same time, there were improvements in photoengraving, lessening the need for a large negative.

Shel B

mcveed, you are a logical man. Some folks made this discussion waaaaaaaaaaaaaaaaaaaay harder than it needed to be. :)

wj cody Loc: springfield illinois

you are correct. and it should be noted that 95% of photographs in the film decades were made with 50mm lenses, in slr cameras. for rangefinder cameras with interchangeable lenses, 35mm was the preferred focal length.

Tomcat5133 Loc: Gladwyne PA

I will wrap this up with every camera I saw when i started in my twenties came with a 50mm lens.
Most never bought another lens. That was the camera setup. And it wasn't called kit lens.