"New" super-8 camera to market

[Guest Glenn Brady]

A CS mount is not a bad idea.

 

CS mount lenses tend to be cheaper than C mount lenses because they tend to use less glass. They don't have to support as large a frame size as the majority of C mount lenses do. So that sounds sort of a good reason to use such.

 

And one could always use a C to CS adapter in order use a C mount lens.

 

C

 

 

For reasons already given, a CS-mount lens can't be used on a C-mount camera. The ffd for a CS-mount lens is five millimeters shorter than a C-mount lens so, even if it could be made to fit the camera physically (those I've got couldn't), it's not going to work optically. I doubt that a wide-angle conversion lens screwed to the front of a CS-mount lens fitted to a C-mount camera would bring an image into focus and, given the lousy quality that's likely to result, I think it isn't worth considering.

 

C- to CS-mount adapters are used to fit C-mount lenses to CS-mount cameras, not the other way around.

Edited August 29, 2013 by Glenn Brady

[Lasse Roedtnes]

Hi All,

 

It's incredible how much this thread has evolved during the last month or so - thanks for the many replies it confirms us in the belief that there's a need for a new camera.

 

I'll keep replies short and to the point this time as I'm travelling abroad.

 

We will only do C-mount.

CS mount is not an option due to the design of our 45 degree oscillating mirror shutter.

The other mounts mentioned will not be implemented either due to lack of space etc.

 

We have tested the following lenses with our camera so far...

 

Schneider Optivaron 6-66mm

Zeiss Tevidon 10mm

Cooke Kinetal 9mm

Pentax 8-48mm

 

For those interessted in buying used lenses I can reveal that we actually bourght the Schneider lens on eBay for a bargin and had that collimated later on.

 

Regards

Lasse

[Benjamin Dietze]

So Carl, let's rehash what we're going on about. I started talking about lenses and focal lengths because angle of view is *NEVER* the same once you change the format, because I want an angle of vision of 100° or higher in every format, and most C-moutn lenses were made for much larger formats than Super8. Ever since then, you have been trying to tell me that angle of vision always stays the same as long as you're staying within the same format. Once I've made you understand that we're talking about the format factor here because most of the lenses were made for different formats, you're trying to tell me I'm confusing angle of vision with light circle, before going on about angle of vision staying the same within the same format again.

And you're trying to tell me that I've got something wrong here?

 

And welcome back, Lasse. Have you seen the very low-priced mount options with P + S that somebody posted here? They'd custom-make your mounts for a price that will be pretty low for us as the end customers down the line as long as you'll have a series (say, 10?) of cameras made with each mount, and some customers may even ask for a multi-mount camera where we'd only have to use a screwdriver to switch the front plate or something, and replace it with the other one(s) from the set.

Edited August 30, 2013 by Benjamin Dietze

[Carl Looper]

 

For reasons already given, a CS-mount lens can't be used on a C-mount camera. The ffd for a CS-mount lens is five millimeters shorter than a C-mount lens so, even if it could be made to fit the camera physically (those I've got couldn't), it's not going to work optically. I doubt that a wide-angle conversion lens screwed to the front of a CS-mount lens fitted to a C-mount camera would bring an image into focus and, given the lousy quality that's likely to result, I think it isn't worth considering.

 

C- to CS-mount adapters are used to fit C-mount lenses to CS-mount cameras, not the other way around.

 

I was suggesting a CS mount camera.

[Carl Looper]

 

So Carl, let's rehash what we're going on about.

 

 

 

Benjamin wants to rehash the story. Ok then.

 

I said: "So for example, any 7mm lens, whether it was made for Vistavision cameras, or for 35mm cameras, or for 16mm cameras, they will all give the same angle of view on Super8."

 

Benjamin said "Wrong"

 

Plain and simple. He said "wrong".

 

That was an intervention in a conversation I was having.

 

Carl

Edited August 30, 2013 by Carl Looper

[Carl Looper]

And this is where MY particular conversation started:

 

 

Posted 26 August 2013 - 04:36 AM

Carl Looper, on 26 Aug 2013 - 8:43 PM, said:

However, it doesn't really matter what focal length you call "normal" - the important point is that all lenses of the same focal length will give you the same angle of view on a given camera. So for example, any 7mm lens, whether it was made for Vistavision cameras, or for 35mm cameras, or for 16mm cameras, they will all give the same angle of view on Super8.

 

Carl,

 

Are you sure?

I am not.

 

Some years ago, I've rented a Super16 camera package from a house. They have all my selections for the lenses, but one. They offered me a 35mm format lens instead of. The one not available and the offered were the same F/. Then I suspected of that lens giving me the angle of view I want.

 

So I have posted on Cinematography.com and the best answer came from Mr. David Muellen, ASC, who is very knowledgeable DoP and seen on the posts mostly.

 

Any lens made for a format, when used in a smaller format than its created for gives narrower angle of field!

 

Any thoughts?

[Carl Looper]

And I have intervened in conversations Ben was having where I thought it necessary to correct errors he was making.

 

For example, here is where Ben is trying to "explain" why focal length figures should not be put on lenses ...

 

Benjamin Dietze, on 27 Aug 2013 - 11:11 AM, said:

Benjamin Dietze, on 27 Aug 2013 - 11:11 AM, said:

 

The smaller your format (blue rectangle), the more it crops from the sides of the image you woulda gotten with a larger format (red rectangle) at the same focal length. Which is why it's stupid to stick to focal length figures for 35mm in an age where most formats we have indeed have little to do with the dimensions of 35mm Full-Frame or 35mm Academy, even in consumer still photography. What would be much more intuitive would be giving a lense's field of vision for any given format size.

 

Percentage of image area of 35mm = Percentage of field of vision you'd have with 35mm (I think).

 

Benjamin would have us believe that it is stupid to put focal length figures on lenses.

 

He thought that focal length figures had something to do with film format. He speaks of "focal length figures for 35mm" and goes on to suggest that because most formats have little to do with the dimensions of 35mm that this means we shouldn't use focal length figures for that reason

 

So to correct this particular argument (and not any others) I've been saying focal length figures are independant of film format. Because they are.

 

There is no such thing as "focal length figures for 35mm".

 

However Ben's new reason is not bad. The maths can be difficult. So I'd agree with that - a lookup table would be a good substitute. Won't help the writer of the lookup table of course.

 

Carl

[Aapo Lettinen]

Focal lenght & field of view IS the same, no matter what format the lens is originally made for.

However, lenses can have different projections (image geometry) which can cause differences in field of view. This is not a format matter, however.

AND, prime and zoom lenses, even the very good ones, can have different actual focal lenght than the markings indicate (!!)

The difference is usually not more than couple of millimeters, but can easily cause the perceived difference in FOV between the "same focal lenght" lenses <_<

 

Lens is usually considered a macro lens when the closest focus distance is under 10 times the focal lenght of the lens

[Carl Looper]

Focal lenght & field of view IS the same, no matter what format the lens is originally made for.

However, lenses can have different projections (image geometry) which can cause differences in field of view. This is not a format matter, however.

AND, prime and zoom lenses, even the very good ones, can have different actual focal lenght than the markings indicate (!!)

The difference is usually not more than couple of millimeters, but can easily cause the perceived difference in FOV between the "same focal lenght" lenses <_<

 

Lens is usually considered a macro lens when the closest focus distance is under 10 times the focal lenght of the lens

 

Focal length and field of view are not quite the same thing. One can, of course, think of it that way but you can run into a lot of trouble with this train of thought.

 

Focal length is a feature of the lens only. It describes an important feature of the lens. In particular it describes the distance between the lenses centre of projection and the film plane. It is not a number that depends on film format. The focal length of a lens remains the same no matter what film format you use the lens on.

 

Field of view differs from this insofar as field of view does depend on what film format (or sensor format) you are using. Using the same focal length lens on a different format camera will give you a different field of view. What it won't do is give you a different focal length.

 

A lens of a particular focal length remains the same focal length regardless of what film/sensor format you use it on.

 

Carl

Edited August 30, 2013 by Carl Looper

[Erkan Umut]

Lasse,

 

The term oscillating confuses me, is it rotating mirror shutter (360°total, inclined at 45° relative to the aperture). As far as I know, oscillating is used for a mirror body (the mirror inclined at 45°) connected to off-center (eccentric) disk to give the left right or vice versa movement...

[Andries Molenaar]

Lasse,

 

The term oscillating confuses me, is it rotating mirror shutter (360°total, inclined at 45° relative to the aperture). As far as I know, oscillating is used for a mirror body (the mirror inclined at 45°) connected to off-center (eccentric) disk to give the left right or vice versa movement...

It is oscillating up en down, like in a Beaulieu 4008/6000.

[Carl Looper]

In the following diagram the same focal length lens is depicted, but used on two different film formats, ie. with different widths (w1 and w2).

 

As can be seen the focal length (F) of each lens is the same. But what is not the same is the field of view (a)

 

Focal length (F) and field of view (a) are not the same thing.

 

Focal length is an important fundamental description of a lens. It allows one to calculate the field of view for whatever film/sensor format one likes including those not yet even invented. The focal length number does not belong to any film format at all. It belongs only to the lens.

 

 

 

 

 

 

Carl

[Aapo Lettinen]

 

Focal length and field of view are not quite the same thing. One can, of course, think of it that way but you can run into a lot of trouble with this train of thought.

 

Focal length is a feature of the lens only. It describes an important feature of the lens. In particular it describes the distance between the lenses centre of projection and the film plane. It is not a number that depends on film format. The focal length of a lens remains the same no matter what film format you use the lens on.

 

Field of view differs from this insofar as field of view does depend on what film format (or sensor format) you are using. Using the same focal length lens on a different format camera will give you a different field of view. What it won't do is give you a different focal length.

 

A lens of a particular focal length remains the same focal length regardless of what film/sensor format you use it on.

 

Carl

You misunderstood my post...

I meant that the field of view of the lenses of particular focal lenght is the same when used in same image format (film/sensor size) ; no matter for which format the lens is originally made for.

[Erkan Umut]

It is oscillating up en down, like in a Beaulieu 4008/6000.

 

Ohh, yes, guillotine...

 

Thanks Andries!

 

 

(For those who want to learn more about these sh*ts, please look at back the diagrams posted as well.)

[Erkan Umut]

If Lasse would start a topic about a new lens for S8 cameras, probably we would discuss about the mechanics instead of optics now :D

[Carl Looper]

You misunderstood my post...

I meant that the field of view of the lenses of particular focal lenght is the same when used in same image format (film/sensor size) ; no matter for which format the lens is originally made for.

 

My apologies. That's absolutely correct.

[Carl Looper]

Perhaps the more interesting question to ask is how do people actually acquire the wrong idea about focal length?

 

This is my theory.

 

What happens is that when one first starts using a camera, as a naive youngster, it isn't actually necessary to know what focal length means. One just looks through the viewfinder and adjusts the lens until one gets the particular angle of view one wants. The numbers on the lens don't really mean anything. And if you are a creative type person you think well, who needs these numbers anyway. One can just look through the viewfinder and compose a shot. The numbers become irrelevant.

 

But as you continue to use the same camera you start to associate the numbers on the lens with the angle of view you are seeing through the viewfinder. The numbers appear to describe the angle of view (in some unknown way)

 

And then you discover, on a different film/sensor format that the numbers and angle of view don't agree with each other in the way they did for the camera on which you first learned to associate focal length with field of view.

 

At this point you can reach the faulty conclusion that the focal length number must have been originally defined in terms of just one format (such as 35mm) and that on every other format the number must be incorrect.

 

And while it's an incorrect theory it is at least a theory and it means you are at least attempting to resolve the disjuncture you've discovered, rather than just ignoring it.

 

The actual disjuncture is not due to some incorrect focal length number or difference in format but is due entirely to the original (and creative) mental association one had made between focal length and what one was seeing in the viewfinder (the field of view). It is a completely understandable error.

 

Anyway, that's my theory on how people come to misunderstand focal length. I'm sure there are other ways as well but this seems to be the most probable train of thought.

 

So if you've ever got focal length wrong - the upside is that it means you are a creative person rather than a possibly boring old fart like me.

 

Carl

[Benjamin Dietze]

 

However, it doesn't really matter what focal length you call "normal" - the important point is that all lenses of the same focal length will give you the same angle of view on a given camera.

 

And that's exactly where you were wrong, and still are wrong. Why did I start talking about "normal" lenses, after all? Because a "normal" lens is defined by the field of vision it gives you in combination with the format you're using. I literally said that a "normal" lens in 16mm or 35mm will be a telephoto lens in Super8. That's where you were butting in and said, "Oh, it doesn't matter, because focal length is always the same, so a 'normal' lens will always be 'normal' ", and that was because a.) you didn't know we're talking about going from one format to another, which was because of b.) that you had no idea what field of vision and the format factor are.

 

 

 

He thought that focal length figures had something to do with film format. He speaks of "focal length figures for 35mm" and goes on to suggest that because most formats have little to do with the dimensions of 35mm that this means we shouldn't use focal length figures for that reason

 

So to correct this particular argument (and not any others) I've been saying focal length figures are independant of film format. Because they are.

 

That was muuuuuuch later after you've already "corrected" me again and again because you had no idea about format factor, field of vision, perspective, focal plane, or many other optics topics. But hey, that's okay! I know little about loss of light and logarithms. But I don't go and claim I do and blame everybody who doesn't agree with my hijinks I come up with because I have no idea about it.

 

And what I was referring to there is the fact that most focal length-field of vision conversion tables are exclusively geared towards 35mm, and it's the only figures most people know about. They "know" that 50mm "is a normal lens", they "know" that 28mm "is a wide lens", and that 18mm "has a field of vision of 100°". They still "know" this if they know anything about focal length, even though they're using way other formats. And why do they "know" all this? Why are those the only tables you only ever come about? Because for most of the 20th century, 35mm was the dominant movie and still photography format in the world, especially in the professional fields where people actually cared about field of vision.

 

That's why people rather buy a new lens, or even new cameras, than having to do the math. Because there's hardly any conversion tables around for any other formats beside 35mm.

 

And it shoulda been obvious for you after everything I'd already told you again and again about the format factor by then.

 

Focal lenght & field of view IS the same, no matter what format the lens is originally made for.

However, lenses can have different projections (image geometry) which can cause differences in field of view. This is not a format matter, however.

 

Not once you go and take the same lens and use it on two different formats. See http://en.wikipedia.org/wiki/Crop_factor Which it was we've been talking about all the time, even before Carl came in and claimed that a "normal" lens will always be a "normal" lens, no matter what format we're using it for.

Edited August 31, 2013 by Benjamin Dietze

[Carl Looper]

Of course some people just don't want to get it.

 

It is true that "most people" (whoever they are) don't care about what focal length actually means. They want to know the angle of view.

 

And if they don't understand what focal length means they'll use a look up table to convert focal length into a field of view. Even professional's use look up tables. It's not just idiots who use look up tables. Or to put it another way, when we're under pressure, we're all idiots.

 

Of course, if the only tables available are for 35mm they'll have a problem. So they'll then use "crop factors" to translate one table into another. They might even think the problem with the table is not that it was printed for 35mm but that the lens is using focal lengths (ha ha).

 

The problem here, of course, is not focal length as such, but that the look up table was printed for 35mm rather than for the film format they are otherwise using. Its the table that doesn't work on other formats. It's not the focal length that doesn't work.

 

The simplest solution, for both engineers and cinematographer's alike is to print their own tables. They can either find someone who actually does understand focal length, field of view, and film format to do it. Someone like me. Or they can have a go themselves using a calculator and the formula.

 

Carl

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Carl

[Erkan Umut]

I cannot imagine if my optics professor would post here, too :D

[Carl Looper]

Posted Today, 06:54 PM

Quote

 

However, it doesn't really matter what focal length you call "normal" - the important point is that all lenses of the same focal length will give you the same angle of view on a given camera.

 

And that's exactly where you were wrong, and still are wrong. Why did I start talking about "normal" lenses, after all? Because a "normal" lens is defined by the field of vision it gives you in combination with the format you're using. I literally said that a "normal" lens in 16mm or 35mm will be a telephoto lens in Super8. That's where you were butting in and said, "Oh, it doesn't matter, because focal length is always the same, so a 'normal' lens will always be 'normal' ", and that was because a.) you didn't know we're talking about going from one format to another, which was because of b.) that you had no idea what field of vision and the format factor are. - Benjamin

 

Hi Benjamin,

 

as much as I might "enjoy" having this debate with you it starts to get a bit tiresome when all you can do is just claim I'm wrong and bend the truth about the context for this debate

 

That quote of mine was in response to something Dom said, not anything you said. And I have as much right as anyone else to "butt in" and have my say. Dom was suggesting that a "normal" lens on Super8 is 15mm. Whether that's true or not depends on what convention you are using. But rather than debate that point I wanted to put it aside. Indeed what Erkan went on to say is that the convention he has learned is that a "normal lens" on Super8 would actually result in a figure of 7mm rather than 15mm.

 

But the more important point, and this is what I wanted to say, is that it doesn't actually matter what you consider "normal". Could be 15mm, 7 mm, or any other mm.

 

What I wanted to say and did say is this:

 

"the important point is that all lenses of the same focal length will give you the same angle of view on a given camera"

 

And this is entirely in terms of what was otherwise being discussed at the time, ie. lenses for a Super8 camera - not 100+ degree lenses for any camera. We were talling about lenses for a Super8 camera. Look at the title of this thread. Look at the forum category we're in.

 

Erkan then asked me if this was true.

 

And I went onto explain why it is true. You then intervened, which is entirely your right, to "correct" me on this point. And that's where the debate between you and I began. Because what you were saying, while much of it is actually really good theorisation, did not in any way prove what I was saying was incorrect. you just said I was wrong and went off on your merry tangent. I then tried to work out where you had gone wrong. You must have gone wrong somewhere because what I was saying was correct. Still is correct.

 

I thought, incorrectly as it turns out, that perhaps you were thinking in terms of lens circles. But as you said that wasn't your problem. So I apologise for that. Nothing I said about lens circles was wrong by the way. It's all true. I just hadn't found where you had gone wrong.

 

Be that as it may, it may be that only you can work out where you've gone wrong.

 

In the meantime, unless you can prove what I've said is wrong, can you please stop saying it is wrong. You do not yet know what you are talking about. I do. It is you who are the "newbie". I've been doing this sort of thing since 1976. All that means is that I'm a tired old fart. It doesn't mean I'm wrong. it doesn't mean I'm right. It just means I'm not a newbie.

 

And what I'm saying deserves far more credit than what you are currently giving it.

 

Carl

[Andries Molenaar]

If Lasse would start a topic about a new lens for S8 cameras, probably we would discuss about the mechanics instead of optics now :D

Some professors prefer to stay off the Internet-forums and social-media and they only have cell-phone with telephone function. Otherwise they never get anything done.

 

Maybe that is wisdom many can take lesson from.

 

And stay away from people who claim the wind blows because the trees move.

Edited August 31, 2013 by Andries Molenaar

[Erkan Umut]

Some professors prefer to stay off the Internet-forums and social-media and they only have cell-phone with telephone function. Otherwise they never get anything done.

 

Maybe that is wisdom many can take lesson from.

 

And stay away from people who claim the wind blows because the trees move.

 

Correct Andries!

 

My Professor Emeritus (Yılmaz Kaini, B.Sc. Ph.D.) would be a sure example. But he is dead 26 years ago...

 

Edited August 31, 2013 by Erkan Umut

[Carl Looper]

 

And stay away from people who claim the wind blows because the trees move.

 

:)

 

Yeah. Good advice. Sometimes you just have to give up. I'm going to do just that. Stay away for a little while ... till the wind blows over.

 

C

[Erkan Umut]

This is a Forum (designated space for public expression), the people are here to discuss, whether its a Prof., student or child...

 

And should not be the place for personal unnecessary hustle and bastle, please guys...