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Film ciné cameras - Standard lens focal length

Doug Kerr

Well-known member
I have very little experience with cinematography, either film or digital.

Somehow I have lately been doing a great deal of research into (and, I'm afraid to say, acquisition of) Kodak ciné cameras from the period 1923-1956.

Although I have regularly railed out against this validity of this notion, when dealing with the 36 mm × 24 mm still camera frame format, we tend to thing of a 50 mm lens as "normal". This is often related to the diagonal frame size, which it about 43.3 mm.

If we now move into the world of 16 mm cinematography, where the standard frame size is about 10.3 mm × 7.5 mm (a diagonal of 12.7 mm), we find that, for the Kodak cameras at least, it is almost universal to furnish them with a lens of 25 mm focal length. This yields a substantially smaller field of view than the fabled 50 mm lens on a full frame 35 mm frame camera.

On the 8 mm ciné camera front, where the frame dimensions are nearly half those in 16 mm work, it was very common to furnish the cameras with a 13 mm lens, the field of view being almost identical to that for the 16 mm cameras.

Do we have any idea what might have led to this custom?

The camera that basically brought an (elegant) end to the Kodak line of 16 mm movie cameras, the Ciné-Kodak K-100, was introduced in 1945 for the single lens version, and 1956 for the three lens turret version (formally called the Ciné-Kodak K-100 Turret). The latter version is often found in the field with lenses of 15 mm, 25 mm, and 102 mm in the turret.

To put this in context, here we see a lovely K-100 (albeit equipped with a rather different stable of lenses):



Kodak Ciné-Kodak K-100 (turret version)

The three things that look like garden hose repair fittings are viewfinder objective lenses, each matched to one of the objective lenses so as to give the viewfinder a field of view matching that given the camera by that objective lens.

Yes, of course, I bought one of these (just today), it having a 15 mm f/2.7 and a 25 mm f/1.9 in the turret, which has room for a further lens and its matching viewfinder lens. (One with a full complement of lenses would be beyond my budget for this project!)

You may note that the lens axes are "splayed" outward, a consequence of the turret being a shallow cone with its apex outward. This arrangement is to militate against the possibility that cohabiting lenses would interfere with one another either physically or by getting in each other's fields of view (the latter of which could well happen if one lens were a wide angle lens and another a physically long telephoto lens).

Just what I need!

Best regards,

Doug
 

Asher Kelman

OPF Owner/Editor-in-Chief
Doug,

You brought to my mind the term "militate", which often is replaced by "mitigate" in our conversations.

"Mitigate is also commonly used in the adjective form mitigating, especially in the phrase mitigating circumstances. ... Thanks to his age and other mitigating circumstances, he was only given a two-year jail sentence. Militate means 'be a powerful factor in preventing something from happening or existing". [Oxford English dictionary.]
 

Asher Kelman

OPF Owner/Editor-in-Chief


Kodak Ciné-Kodak K-100 (turret version)

Doug,

Think how long this venture existed, some decades, that's all! There was so much thought and state of art engineering to make this possible.

Now we do more than this in each yearly iteration of a smart phone.

It is said that revolutions devour their children, but actually their parents, the "prime movers". Think of the line of orators of the French National Assembly that lined up for the Guillotine in Paris. Think of the axe landing in the skull of Trotsky.

We are collapsing thoudands of years of machine and technical evolution in to years and months. With the advent of 3D printing, we will be able to evolve new machines and even medicines in hours.

Asher
 

Doug Kerr

Well-known member
Hi, Asher,

Doug,

You brought to my mind the term "militate", which often is replaced by "mitigate" in our conversations.

"Mitigate is also commonly used in the adjective form mitigating, especially in the phrase mitigating circumstances. ... Thanks to his age and other mitigating circumstances, he was only given a two-year jail sentence. Militate means 'be a powerful factor in preventing something from happening or existing". [Oxford English dictionary.]
Yes indeed.

Another use of mitigate is to diminish adverse results. One can mitigate adverse results of a situation. Or one can militate against the occurrence of those results.

One could certainly think of what is accomplished by the cones turret of the A-100 Turret either way. But I find militate to be more poetically satisfying, and perhaps more potent.

Best regards,

Doug
 

Doug Kerr

Well-known member
Hi, Asher,

Doug,

Think how long this venture existed, some decades, that's all! There was so much thought and state of art engineering to make this possible.
Yes, and a sprinkling of arbitrary decision making!

Now we do more than this in each yearly iteration of a smart phone.
Or more than that is delivered in the weekly software upgrade pushes!

quote]It is said that revolutions devour their children, but actually their parents, the "prime movers". Think of the line of orators of the French National Assembly that lined up for the Guillotine in Paris. Think of the axe landing in the skull of Trotsky.

We are collapsing thoudands of years of machine and technical evolution in to years and months. With the advent of 3D printing, we will be able to evolve new machines and even medicines in hours.[/QUOTE]
Yes, it is wondrous, and sobering.

Carla and I were reading during this morning's news briefing about developments in self-driving cars, especially as it might benefit the elderly. There are of course those who point out that a gaffe in the software, or a failure in the system, could cause a car to run down a pedestrian.

On the other hand, every night at 10:00 pm we read how, during the day, in Albuquerque, several pedestrians had been run down by human-manipulated cars.

Now, over a week's-worth of these misadventures, we find some of the drivers were drunk, and some had some medical episode, and several were distracted by their communication devices, and some were just not paying attention (in the old-fashioned way).

Sic transit gloria mundi.

Best regards,

Doug
 

Jerome Marot

Well-known member
Although I have regularly railed out against this validity of this notion, when dealing with the 36 mm × 24 mm still camera frame format, we tend to thing of a 50 mm lens as "normal". This is often related to the diagonal frame size, which it about 43.3 mm.

If we now move into the world of 16 mm cinematography, where the standard frame size is about 10.3 mm × 7.5 mm (a diagonal of 12.7 mm), we find that, for the Kodak cameras at least, it is almost universal to furnish them with a lens of 25 mm focal length. This yields a substantially smaller field of view than the fabled 50 mm lens on a full frame 35 mm frame camera.

On the 8 mm ciné camera front, where the frame dimensions are nearly half those in 16 mm work, it was very common to furnish the cameras with a 13 mm lens, the field of view being almost identical to that for the 16 mm cameras.

Do we have any idea what might have led to this custom?
Probably, the reason is that taking photographs is a bit different than filming a movie. Wide angles were not necessary for these cameras because:
  • one could not film inside without lights in that era and
  • for landscape, one simply pans the camera around.

On the other hand a longer focal was advantageous for portraits and generally for filming people. Also: the relatively low resolution of home movies made it necessary to fill the frame with the subject. Last but not least, a 100mm "kleinbild" lens is relatively large and 160mm medium format even more so. A 13mm film lens was not.
 

Asher Kelman

OPF Owner/Editor-in-Chief
Probably, the reason is that taking photographs is a bit different than filming a movie. Wide angles were not necessary for these cameras because:
  • one could not film inside without lights in that era and
  • for landscape, one simply pans the camera around.

On the other hand a longer focal was advantageous for portraits and generally for filming people. Also: the relatively low resolution of home movies made it necessary to fill the frame with the subject. Last but not least, a 100mm "kleinbild" lens is relatively large and 160mm medium format even more so. A 13mm film lens was not.
So today, Jerome, if you were building a camera with turret lenses but a digital sensor, what would you choose in format and lenses, given the same considerations of minimizing weight and bulk?

Would it turn out to be a thing like the video cams available for prosumers?

Asher
 

Doug Kerr

Well-known member
Hi, Jerome,

Probably, the reason is that taking photographs is a bit different than filming a movie. Wide angles were not necessary for these cameras because:
  • one could not film inside without lights in that era and
  • for landscape, one simply pans the camera around.

On the other hand a longer focal was advantageous for portraits and generally for filming people. Also: the relatively low resolution of home movies made it necessary to fill the frame with the subject. Last but not least, a 100mm "kleinbild" lens is relatively large and 160mm medium format even more so. A 13mm film lens was not.
All very good points. Thank you so much.

Best regards,

Doug
 

Jerome Marot

Well-known member
So today, Jerome, if you were building a camera with turret lenses but a digital sensor, what would you choose in format and lenses, given the same considerations of minimizing weight and bulk?

Would it turn out to be a thing like the video cams available for prosumers?

Asher
Nobody builds a camera with turret lenses any more. Progresses in optics, particularly the availability of aspherical lenses, have rendered these obsolete as zooms are more convenient and more compact.

As to zoom lenses for camcorders, most have something like an equivalent 24-300mm, give or take some mm at each end. Why? Because long lenses are a selling point (the customer find the idea of a strong telephoto attractive, even if they are not very useful in practice) and because we know can film indoor in available light so a wide-angle is actually useful. Wider lenses are available through converters, but the result tend to look a bit strange when one moves the camera around.

This being said, camcorders are rapidly becoming obsolete on the consumer market.

The closest thing to turret lenses is this:
 
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