So how did the standard lenses become standard? 28mm, 50mm, 135mm

[Shakespeare]

So how did the standards become standards? I know that things weren't always like this, and there are many deviations (Minolta's 45mm manual comes to mind), but what made the most common lengths become the most common?

S

 

[rexbobcat]

They were sold with the camera?

And they are equivalent to the perspective of the human eye so there's less calculating on the photographer's part?

 

[Sw1tchFX]

Yes, they've always been like this, and that's because a standard more or less matches human perspective.

25mm is standard for m 4/3rds
35 for aps-c
50 for 135
80 for 645
110 for 6x7
210 for 4x5
350ish for 8x10

...

 

[enzodm]

I know one part of the question but not the other.
50mm (~) allows to depict more or less what you see (in terms of field and perspective).
The other sizes... I do not know why those, although I suppose it is matter of distance between them, and maybe the first one that did a 28mm has been copied by others for reference. However, typical sizes include also 24mm, 85mm (in the past also 75), 100/105, 200, etc. In addition to that, I'm not sure if it is true for primes too, but zooms have less than precise focal lengths, rounded to standard values.
And different formats, e.g., medium format, have different standards.

 

[Derrel]

The Leica A of 1924 had a 5cm f/3.5 Anastigmat lens...that kind of cast the die I believe for 135-size cameras as to the "normal" or "standard" lens. Before too long, other companies were making "miniature" cameras that had 5cm (aka 50mm) 'normal' lenses. I had always heard that a lens of 50mm focal length was relatively easy to design and manufacture, and have a good all-around optical performance, back in the pre-WW II days.

Some of the earlier focal lengths "stuck" quite nicely, like the 3.5cm wide-angle, while other lengths, like the 65,75,and 90mm lenses had varying lengths of popularity. In the rangefinder days, a 135mm telephoto was about as long as was practical, both for accurate focusing and for decent viewfinder framing. The Leica 90mm was actually MUCH more-popular than 135mm; 135mm is really more of a focal length that caught on in the 1960's, once SLR cameras took over from rangefinder designs.

28mm was a pretty popular wide-angle length for several decades. Leica's M-series 21mm only came into being in the early 1960's I believe. 25mm was more popular than 24mm, until 24mm took over. At various times, 55mm and 58mm "normal" lenses were popular for 35mm SLR cameras.

 

[tirediron]

The Leica A of 1924 had a 5cm f/3.5 Anastigmat lens...that kind of cast the die I believe for 135-size cameras as to the "normal" or "standard" lens. Before too long, other companies were making "miniature" cameras that had 5cm (aka 50mm) 'normal' lenses. I had always heard that a lens of 50mm focal length was relatively easy to design and manufacture, and have a good all-around optical performance, back in the pre-WW II days.

Some of the earlier focal lengths "stuck" quite nicely, like the 3.5cm wide-angle, while other lengths, like the 65,75,and 90mm lenses had varying lengths of popularity. In the rangefinder days, a 135mm telephoto was about as long as was practical, both for accurate focusing and for decent viewfinder framing. The Leica 90mm was actually MUCH more-popular than 135mm; 135mm is really more of a focal length that caught on in the 1960's, once SLR cameras took over from rangefinder designs.

28mm was a pretty popular wide-angle length for several decades. Leica's M-series 21mm only came into being in the early 1960's I believe. 25mm was more popular than 24mm, until 24mm took over. At various times, 55mm and 58mm "normal" lenses were popular for 35mm SLR cameras.

To summarize: "What's normal?"

 

[jake337]

Ask yourself this:

Standing at 10-15 feet from your subject what focal lengths will give you:

1) Wide angle portrait - 28mm
2) Full body portrait - 50mm
3) Half body portrait - 85mm
3) Head and shoulders - 135mm



Well that's how I've always looked at it. I even think it has more to do with the origins of cameras. Think about doing some photography with a view camera way back at when. You weren't running around with a camera in your hand. Your camera was set in place as well as your subjects. No one wanted to move the camera around for different portrait sizes(see above) and no one wanted to move their subjects all over the place as well. So they changed lenses instead. I think how that worked into 28, 50, 85, 135 being standard is that as the format shrunk into carriable sized bodies they simply did the math and found equal FOV for the, now standard, 35mm piece of film.

 

[Derrel]

To summarize: "What's normal?"

Now, that, THAT is a dangerous question to ask of me! Even with a winky/smiley emoticon after it! lol

 

[tirediron]

To summarize: "What's normal?"

Now, that, THAT is a dangerous question to ask of me! Even with a winky/smiley emoticon after it! lol

Not at all, because we know the answer. There's NOTHING normal about Derrel!

 

[christop]

A lens is considered "normal" if its focal length is close to the diagonal of the format. 135 film has a diagonal of about 43mm, so any lens near that is a "normal" lens. 50mm also happens to have the same magnification in many 35mm SLR viewfinders as an unaided eye. I think this is also where the myth that a 50mm lens has the same "perspective" as the human eye came from.

Now I'm just speculating, but I believe "standard" focal lengths were chosen based on their distances to nearby focal lengths. Take the ratio between a few common focal lengths:

35 / 24 = 1.458
50 / 35 = 1.429
85 / 50 = 1.7
135 / 85 = 1.588
200 / 135 = 1.481

All of the ratios are close to each other (between 1.4 and 1.7). It wouldn't make much sense to use both a 50mm lens and a 58mm lens (unless one lens has special abilities, such as macro focus) because 58mm is only 16% longer than 50mm. If 50mm is not long enough, it makes more sense to use a 70mm or 85mm lens instead. If 50mm is not long enough but 70mm is too long, you can compensate by using either 50mm or 70mm and moving position ("zooming by foot") or by using 50mm and cropping later. You would have to compensate by only 40% or less in this case.

I don't know exactly why these particular focal lengths are the most common, as opposed to something like 22/30/45/72/110. It could be that they became de facto standards when camera/lens manufacturers made lenses in those lengths and other manufacturers followed suit.

 

[Big Mike]

There was an article posed here a while back...a very interesting read about the origins of lens design and how pretty much all lenses can be traced back to one of six different designs. As Derrel mentioned, a 50mm lens has a rather simplistic design which is probably one good reason why it's been a 'standard' lens for the 35mm format.

 

[Shakespeare]

Awesome info, all. Thanks for the facts and opinions. Makes you wonder why 50 won out over 58, 135 over 150, 85 over 90, etc.

Then again, this is not the last age of camera lenses. 62mm and 123mm may some day rule!

S

 

[LungFish]

Surely the fact that 50 is a round number must have something to do with it for 135 format, otherwise we'd all be using 45mm lenses. Once you have one 'standard' length, the others follow.

 

[Mully]

I like the 51 mm lens the best.

 

[Mike_E]

Best guess?

They were probably the easiest focal lengths in their range to get right.

The demand for the general angle of views was always there so there were going to be lenses in those ranges. Manufacturers are like people in that they tend to follow the paths of least resistance.