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Author Topic: Where does the 24/35/50/85mm standard originate? Is it arbitrary?  (Read 11941 times)

unfocused

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #15 on: July 30, 2013, 06:32:00 PM »
I think some of it has to do with the evolution of lenses and cameras.

Remember that using 35mm movie film started with rangefinders. 50mm does match the human eye in some respects. I have always read that 35mm became the standard wide angle because it gave a wider field of vision without much distortion. 85mm became the standard portrait lens because it was more flattering. I suspect that for many years those were the standards because on a rangefinder a much wider or longer lens was difficult to manage.

Probably just carried over to the SLRs.

Doing a quick search, it looks like Leica introduced the 35mm in 1930; the 73mm, 90mm and 135mm in 1931 and the 105 mm in 1932.

Back in the 70s I know from personal experience that 28mm, not 24, was considered the standard wide angle lens when you needed something wider than 35 mm and 135mm was the standard telephoto lens. I suspect that as lens technology improved lenses got wider and longer.

As to why it is, say 135mm rather than 125mm or 140mm, I have no idea. Obviously, from the above, the standards were a bit more variable back in the early days of Leica.
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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #15 on: July 30, 2013, 06:32:00 PM »

gferdinandsen

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #16 on: July 31, 2013, 05:45:31 AM »
Looking at my last photoshoot, those focal lengths are the most used.  Using primarily the 24-70 and to a lesser extent the 24-105:

Total: 396
24: 116
35:  29
40:  16
50:  13
85:  20

This is consistent with all of my folders.  So to answer your questions, it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!
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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #17 on: July 31, 2013, 11:48:48 PM »
it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!

That does seem uncanny that a disproportion of your shots landed on "standard" lengths. While you were shooting, were you aware of the focal lengths you were using?

I'm completely skeptical that 50mm is any more inherent or "gravitational" than, say 45mm, 55mm, or any other focal length that is near a standard prime focal length.

Going one step further, I would guess that most people couldn't land on a specific focal length IF THEY TRIED TO. I'm guessing the margin of error would be around +/- 5mm for those who tried.

Few would debate that there are certain focal lengths that work well for certain types of shots. But my original question was really about why the standard focal lengths are PRECISELY 24/35/50/85mm, and not +/- 5mm off of those lengths.

gferdinandsen

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #18 on: August 01, 2013, 06:40:41 AM »
it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!

That does seem uncanny that a disproportion of your shots landed on "standard" lengths. While you were shooting, were you aware of the focal lengths you were using?

I'm completely skeptical that 50mm is any more inherent or "gravitational" than, say 45mm, 55mm, or any other focal length that is near a standard prime focal length.

Going one step further, I would guess that most people couldn't land on a specific focal length IF THEY TRIED TO. I'm guessing the margin of error would be around +/- 5mm for those who tried.

Few would debate that there are certain focal lengths that work well for certain types of shots. But my original question was really about why the standard focal lengths are PRECISELY 24/35/50/85mm, and not +/- 5mm off of those lengths.

I find the same holds true to all my trips, with 24mm being my favourite focal length.  It's even more uncanny if I include prime focal length +/- 2mm.

And no, I don't choose focal lengths based on focal length.  I just compose the photo and shoot.
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rcarca

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #19 on: August 01, 2013, 08:14:50 AM »
Classic film before 35mm was 72mm but 35mm (which is actually 36mm) rapidly became the dominant film standard. If you use Pythagoras theorem, you will note that the square root of the hypotenuse (the diagonal on the film) equals the square root of the sum of the square of the two other sides of the triangle (24mm and 36mm)For 35mm format film that gives approximately 43mm. That is the perfect match for what the human eye sees. That got rounded up to 50mm for most purposes. I rather suspect you will find similar relationships with other standard film sizes, although I have never done the maths.

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preppyak

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #20 on: August 01, 2013, 09:24:17 AM »
Like apertures, common focal lengths tend to follow multiples of the square root of two.

So, 24 (close to 25), 35, 50, 70 (OK, that's not a good example as 85 is used instead), 100, 135 (close to 141), 200, 300 (close to 283), 400 etc.

I think a useful thing to remember is that a 50mm lens is rarely actually exactly 50.00 on the patent. Just like a 70-300 zoom is usually actually a 71.89 to 292.35 lens, but, they round it to make it simpler. Note that, 24mm aside, all those numbers land on a 0 or a 5. Just makes the numbers simpler. It's actually interesting to me that 14mm and 24mm are standard instead of 15mm and 25mm, because you could market it the same.

An example of this are the 100-400 patents. Technically the lens should be marketed as a 104 to 391, but they round it off to keep it simpler

So, to answer the OP, it's a combo of science and BS. The lenses all match a certain field of view and preferred look, but, the number that represents them is not always accurate

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #21 on: August 01, 2013, 10:24:14 AM »
It's actually interesting to me that 14mm and 24mm are standard instead of 15mm and 25mm, because you could market it the same.

Actually, with such short focal lenghts, 1mm makes quite a difference. For example, many years ago, Zeiss and Pentax produced the great and famous 15mm f/3.5 Aspherical (fow 86°). After that, Canon produced a 14mm f/2.8 (fow 90°) probably to show off a wider ad faster lens. The same thing most likely happend after Leica produced the first 25mm for a 35mm camera. So, I suppose that current standard focal lenses became standard for various reasons and technical improvements are definitely one of them.

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #21 on: August 01, 2013, 10:24:14 AM »

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #22 on: August 01, 2013, 11:08:31 AM »
Classic film before 35mm was 72mm but 35mm (which is actually 36mm) rapidly became the dominant film standard.

I'd dispute the first claim, after all what do you mean with the term "classic film"? But anyway, regarding 35mm film "which is actually 36mm" you couldn't be more wrong, roll film is measured by its film gauge, that is, it is 35mm wide, hence 35mm film, it has nothing to do with the arbitrary dimensions of the film we expose. Look at the Hasselblad X-Pan with a 24mm x 65mm exposure area on 135 format film. Don't forget we, as still photographers, are actually using film in the "wrong" orientation to its primary original purpose, running through movie cameras and theater projectors.

As for "standard" lenses being the diagonal of the format, yes that holds up across formats.
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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #23 on: August 01, 2013, 11:31:25 AM »

Awesome thread.  I've always wanted to know this.  I understand fully well why certain lengths in general are used, but I've never understood how they landed on the specific focal length values.

- A

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #24 on: August 01, 2013, 12:38:58 PM »
it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!

Few would debate that there are certain focal lengths that work well for certain types of shots. But my original question was really about why the standard focal lengths are PRECISELY 24/35/50/85mm, and not +/- 5mm off of those lengths.

They are not precisely 24/35/50/85  .... they are just labelled that way by the manufacturer for easy marketing I suspect. They are all off by a bit.  Zoom ranges can be quite a bit off.

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #25 on: August 01, 2013, 02:41:34 PM »
"Normal" focal length for 35mm film is 43mm, which got rounded up to 50 by Oskar Barnack. The idea behind the progression of primes is this:

A 75mm lens will give you roughly the same framing from top to bottom when used in portrait orientation as a 50mm would when used in landscape. Put another way, if you took a photo take at 50mm in landscape orientation and cropped away the left 1/3 and right 1/3 of the frame, you'd get roughly the same image as if you used a 75mm lens in portrait orientation. Kind of awkward to describe so I hope that makes sense.

So, it's not completely arbitrary. All primes are multiples of 43mm or 50mm (1.4x, roughly the square root of 2, much like f-stops). "Normal" focal lengths for larger formats are also familiar numbers: 85mm (medium format), 200mm (large format) etc.

+1

nice to learn about this part of photography history. Thanks!
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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #26 on: August 01, 2013, 03:07:13 PM »
it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!

Few would debate that there are certain focal lengths that work well for certain types of shots. But my original question was really about why the standard focal lengths are PRECISELY 24/35/50/85mm, and not +/- 5mm off of those lengths.

They are not precisely 24/35/50/85  .... they are just labelled that way by the manufacturer for easy marketing I suspect. They are all off by a bit.  Zoom ranges can be quite a bit off.

Good point! And that begs the question even further. A few possible scenarios...

1. There are true "standard" focal ranges (e.g. +/- 2mm) around the 24/35/50/85 marks; and, for marketing purposes they have always rounded to a number that sounds good.

2. There are no inherent or intrinsic "standards" and everything is just a product of arbitrary historical precedent.

Personally, I think the standards are arbitrary. Great shots can be had at any focal length.

I think the reason why people accept the standards (and some believe they are baked into the fabric of life) is that they do serve successfully as guides for choosing lenses and composing shots. But it would seem to me that in a parallel universe (or by quirk of history)... 22/32/46/80 could just as easily be the standard focal lengths.

On a side note, I should point out that the most commonly used focal lengths (35mm equivalent) are probably...

Samsung Galaxy S III: 26mm
iPhone 5: 33mm
iPhone 4s: 33mm
iPhone 4: 29mm
HTC One: 27.54mm

From this we can see how marketing departments might be tempted to round up or down to 28mm and 35mm. Certainly "27.54" has a bad ring to it. And if rounding up or down by 0.5 is no sin, then surely rounding by .75 or even 1.75 is no sin either! ;-)

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #27 on: August 01, 2013, 03:20:48 PM »
it seems that we just naturally gravitate towards certain focal lengths; even with a zoom, we tend to choose prime focal lengths more so than we choose non prime.

I always find it interesting to look at the focal lengths of my photoshoots, I find it amazing just how often they do gravitate towards primal focal lengths.  But then again, there are lies, damned lies, and statistics!

Few would debate that there are certain focal lengths that work well for certain types of shots. But my original question was really about why the standard focal lengths are PRECISELY 24/35/50/85mm, and not +/- 5mm off of those lengths.

They are not precisely 24/35/50/85  .... they are just labelled that way by the manufacturer for easy marketing I suspect. They are all off by a bit.  Zoom ranges can be quite a bit off.

Good point! And that begs the question even further. A few possible scenarios...

1. There are true "standard" focal ranges (e.g. +/- 2mm) around the 24/35/50/85 marks; and, for marketing purposes they have always rounded to a number that sounds good.

2. There are no inherent or intrinsic "standards" and everything is just a product of arbitrary historical precedent.

Personally, I think the standards are arbitrary. Great shots can be had at any focal length.

I think the reason why people accept the standards (and some believe they are baked into the fabric of life) is that they do serve successfully as guides for choosing lenses and composing shots. But it would seem to me that in a parallel universe (or by quirk of history)... 22/32/46/80 could just as easily be the standard focal lengths.

On a side note, I should point out that the most commonly used focal lengths (35mm equivalent) are probably...

Samsung Galaxy S III: 26mm
iPhone 5: 33mm
iPhone 4s: 33mm
iPhone 4: 29mm
HTC One: 27.54mm

From this we can see how marketing departments might be tempted to round up or down to 28mm and 35mm. Certainly "27.54" has a bad ring to it. And if rounding up or down by 0.5 is no sin, then surely rounding by .75 or even 1.75 is no sin either! ;-)

+1

Super insightful comment -- great thinking.  Smartphone makers don't have to satisfy the 1% of the population that appreciates 'standard' focal lengths.  Instead, I'd imagine Apple, Samsung, etc. mined what focal length people tended to shoot and built their 'standard' around that.

And it should be no surprise where they landed, really.  Most people aren't shooting tightly cropped headshots with their phones.  So lenses in the 24-35 neighborhood play very well with users.

-A

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #27 on: August 01, 2013, 03:20:48 PM »

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #28 on: August 01, 2013, 06:14:34 PM »
But anyway, regarding 35mm film "which is actually 36mm" you couldn't be more wrong, roll film is measured by its film gauge, that is, it is 35mm wide, hence 35mm film, it has nothing to do with the arbitrary dimensions of the film we expose.

Let me be more precise. The gauge (from edge to edge of the film including the sprocket holes) is 35mm. The area we exposed on a 35mm film was 24 x 36mm. That is the relationship that drives the "standard" lens.

I will research further on the relationship with cinema film.

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #29 on: August 01, 2013, 09:11:17 PM »
The diagonal of the 36 X24 mm film is 43. 27mm. It was rounder up to 45mm. A lot of fixed lens 35mm film cameras from the 40's to the 60's are 45mm lens. It also happens that is about the same"clear viewing " angle of the human vision. Leica further round it up to be 50mm. Here comes the film SLR in the 30's. Due to the mirror,  it is hard (expensive) to make a 50mm standard lens. Therefore 55mm became the standrd SLR lens until the 50's or even early 60's. So the 50mm standrad focal length is semi arbitrary. For the "portrait lens", Leica arbitrarily assign the 90mm focal length, while others are using 85, 100 or 105mm. 135mm is the longest focal length that Leica feel comfortable with their range finder camera without additional attachment.  Leica does  make longer focal length for their visoflex reflex housing. Since Leica is the premium and propular range finder camera in the 50's, the 135 mm beomes a "standard". 35mm  (0.7X of 50 mm) is the comfortable "wider' angle of view to have a easily controllable perpective distortion. It became a standrad also. 24 mm  is 0.7X of 35mm and becomes another standard with large perspective  distortion that is not that easy to control. Then 28mm is right between the 35mm and 24mm in terms of viewing angle to be wider than 35mm and more controllable perpective distortion than the 24mm.
« Last Edit: August 02, 2013, 03:25:30 AM by Rocky »

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Re: Where does the 24/35/50/85mm standard originate? Is it arbitrary?
« Reply #29 on: August 01, 2013, 09:11:17 PM »