Super 16 & 35mm Lenses

I may have this all wrong.

Shooting Super 16 with 35mm Zeiss super speeds. The guy at the rental house is telling me 35mm lens double in focal length if used on super 16mm cameras. I've done this a couple of times before and I don't remember the focal length doubling.

He's saying that since 35mm lenses are made to cover twice the area of Super 16 all of the light is focused on the half side of the frame, and that it doubles the focal length…which does make sense, but I've never heard that it does that.

It does make sense though.

Tenolian Bell
Cinematographer NY

Tenolian Bell wrote :

>The guy at the rental house is telling me 35mm lens double in focal >length if used on super 16mm cameras.

Change rental houses.

A 50mm lens = a 50mm lens, no matter what format you're shooting, as long as it covers.

Note that the field of view of a 50mm lens on 35mm will be significantly wider than the same lens used on a 16mm camera, but a 35mm-format 50mm lens will have the same field of view as a 16mm-format 50mm lens.

This has been discussed many times here, and, really, it's kind of amazing that people still make statements like this.

Perhaps he meant to say something slightly different, like "a 25mm lens is 'normal' (whatever 'normal' means) on a 16mm camera, and a wide angle on a 35mm camera?

But the focal length remains the same -- 50mm = 50mm.

Jeff Kreines

Wrong! A 50mm is a 50mm is a 50mm that's all there is to it.

This is a common misperception.

50mm on 16 looks longer(tighter) than it does on 35. However it makes no difference if the lens covers 35mm frame or not.

If you compare a 16mm 50mm lens to a 35mm 50mm lens they will have the same field of view.

I actually had to prove this to a "DP" once at prep.

Bret Lanius

Try this, put up a 25mm focal length for super 16, mark the framed area, now out up a 25mm for the 35mm format' now compare the two image area.

Stacy Strode

Tenolian

I'd really like to know what guy, and at what camera rental house here in New York told you this.

Either you heard him very wrong or he seriously should not be working at a professional motion picture camera rental facility.

Mitch Gross
NYC DP

The thing that makes me laugh (or cry) about this the most is that it took place at a camera rental house, where it would have taken all of two minutes to prove the guy wrong.

Mitch Gross
NYC DP

>The guy at the rental house is telling me 35mm lens double in focal >length if used on Super 16 cameras.

As someone who spent his first two years, seven months, a week and two days working in a rental house, I can tell you authoritatively that :

A/. This guy doesn't know what he is talking about and you should find someone else at the rental house to deal with--or a different rental house.

B/. In the manner of many jerks he is talking confidently about something that he has not learned from actual experience or from people who actually know what they're doing. If he had any common sense he would have subjected this idea to some physical testing, though a simple 'thought experiment' ought to clear it up. Maybe that was too much work and it was easier to just pronounce things without verifying them. I am awfully tempted to suggest he has missed his chance to work in the current White House, where this style of reasoning and discourse is quite popular, but that would be getting into politics, which I know Geoff frowns on, and quite rightly too.

C/. Unfortunately the rental house environment can occasionally create such monsters, people who confuse a certain isolated knowledge of camera equipment with knowledge of cinematography. Sometimes people like this go out and become camera assistants. They are recognizable because they're the ones who insist that production wait while they check the f-f depth--again. Later on they get to wait--by the phone.

50mm is 50mm, whether Primo for 35, or Zeiss SS for 16.

However, 50mm renders a different *image size* on 35mm than on 16, or for that matter on 35mm still, or on 4x5, or VistaVision, or whatever.

What he might have heard about--and misunderstood--was that if you want the effect of a 50mm in 35mm, but are shooting 16, you will get (roughly) the same effect with a 25mm. (Super 16 will be the same vertically but obviously wider horizontally.)

It's not that hard.

Or maybe I've been wrong all these years and it actually IS rocket science?

Alan Thatcher
DP
Chicago

>As someone who spent his first two years, seven months, a week and >two days working in a rental house, I can tell you authoritatively that :

I meant first two years (...) IN THE BUSINESS … I haven't been around THAT long.

Alan Thatcher

Alan Thatcher wrote :

>I am awfully tempted to suggest he has missed his chance to work in >the current White House

Or, as they say, Faith-Based Focal Lengths...

Jeff "like a prayer" Kreines

Tenolian Bell wrote :

>He's saying that since 35mm lens are made to cover twice the area of >Super 16, all of the light is focused on the half side of the frame, and that >it doubles the focal length, which does...

Which does..... exactly what?

It doesn't double the focal length. It just gives the lens greater covering power, and, of course, when you're dealing with wider lenses it's harder to make them cover a larger aperture, which means a 10mm lens that covers the 35mm cine aperture costs more than a 10mm lens that only has to cover 16mm.

Jeff Kreines

So after all this. If you use 35 lenses on S16 it remains its original length. Fine, but is there a direct formula to the general rule that 16m lenses are tighter then 35 lenses. Does it fluctuate as it goes up and down or is there a constant?

In other words. If I shoot a 10mm on 35 I would need 6mm in a 16 lens (ballpark) to achieve the same distortion, field of view, etc. Does that same ratio apply to wider and longer lenses or does it fluctuate?

Chris Sargent

The relative relationship is constant. I must say I'm continually amazed at the professionals who have trouble with this. It has to be the single most misunderstood concept in the industry right next to how the DVX100 records 24p onto 60i. Amazing. Next thing you know someone will tell me that there are no magic imps at the lab making all the pretty pictures. I know they're there--I've seen them (and they're often union)!

Mitch Gross
NYC DP

The shoot is in LA. Actually this is at a well known rental house based in NY, but has a office in LA. This rental house has a great deal of experience with super 16. I haven't met the guy, I put the order in to the producer. The producer calls me back and tells me this is what the guy at the rental house told him.

This rental house has a great deal of experience with super 16 and I didn't really feel like calling the guy and arguing with him. But before I did I wanted to make sure I'm not the crazy one.

I may or may not have time to mount lens' on the camera to prove him wrong. So what should I tell him when ever in inevitably speak to him?

Tenolian Bell

>The producer calls me back and tells me this is what the guy at the >rental house told him.

>I may or may not have time to mount lens' on the camera to prove him >wrong. So what should I tell him when ever in inevitably speak to him?

Tell him that your producer clearly did not understand what he was told and that it made for a fun short thread on the CML. I'm sure that the guy read it himself on the list and thought, "I wonder who it was that could say such a dumb thing." Little did he know it was himself and there was just a moron (read: producer) who translated the message completely incorrectly. I'm sure everyone on Willow Ave. had a nice laugh.

Mitch Gross
NYC DP

Is there a formula or ratio, to sort this out for me and the imps.

Chris Sargent
Dir/DP
Toronto

Jeff Kreines writes :

>This has been discussed many times here, and, really, it's kind of >amazing that people still make statements like this.

Yes, and I like the way Jon Fauser puts it - if you're using 35mm format lenses(Motion picture or stills ones for that matter)on a 16mm camera, you're just carrying "extra glass" around.

Worthy of discussion is the "sweet spot" as some people call it - Is it worth it to use 35 mm format lenses in 16mm because the back element is much wider, or is it because more R&D goes into the 35mm format lenses?

My 50mm Contax converted to Aaton mount has a much wider rear element than a motion picture 50mm 35mm format Zeiss-but I know there's more to this and I think manufacturers don't necessarily want a wide rear element-could someone post about 35/16 lens resolution once again?

I believe some of it has been covered before.

Best regards,
John Babl
Miami

In theory a lens that is designed only to cover a 16mm (or Super-16) gate area can achieve a greater resolving power than a 35mm lens because it doesn't have to jump through as many hoops. A lens that covers 35mm needs to try to keep sharpness, brightness, reticular distortion and chromatic distortion to a minimum all the way to the corners of the frame. In keeping the corners acceptable there are a number of compromises that lower these same qualities to some degree in the frame centre. A lens for Super-16 has a much smaller area to deal with so doesn't have to compromise as much.

That of course, is just theory. In practice the R&D that goes into 35mm format lenses is far greater than 16mm glass, so the performance factors between these lenses is near identical if not better within the Super-16 frame. This can be tested easily by measuring MTF, shooting some chart tests and simply putting up the lenses on a common lens projector at any decent rental house. I really recommend every DP pay a visit to the back room at their local rental house and take a look at some lenses on a projector. So many characteristics that are discussed here and in various books become instantly visible and clear when projected in front of you.

Mitch Gross
NYC DP

John Babl wrote :

>but I know there's more to this and I think manufacturers don't >necessarily want a wide rear element-could someone post about 35/16 >lens resolution once again?

Sometimes, with a lens that casts too large a cone of light, and isn't masked, you'll get light bouncing off parts of the camera that light doesn't normally strike, and it can either lower contrast or introduce artefacts.

I've had this happen in optical printers.

Jeff Kreines

Jeff Kreines wrote :

>Sometimes, with a lens that casts too large a cone of light, and isn't >masked, you'll get light bouncing off parts of the camera that light >doesn't normally strike, and it can either lower contrast or introduce >artefacts.

I use some 35 mm lenses on my Mitchell Reflex 16 when doing time lapse. Yes they can induce artefacts because they are spraying light all over the place as compared to a 16 lens. And this is with a camera that has a pretty light tight shutter compared to an Aaton or SR or any other non focal plane shutter camera for that matter. Be careful especially with light sources especially as they get towards corners of
the frame.

Mark Smith
Oh Seven Films
143 Grand St
Jersey City, NJ 07302

Chris Sargent writes :

>...is there a direct formula to the general rule that 16m lenses are tighter >then 35 lenses. Does it fluctuate as it goes up and down or is there a >constant?

To rephrase as simply as humanly possible what others have been saying, let's assume you're shooting a picture of a barn.

1) A lens of X focal length lens will always project an image of the barn at Y size on the image (film) plane.

2) 16mm film, being smaller than 35mm, receives a smaller portion of that projected image. So the 35mm frame might include the whole barn, but the 16mm frame will include only the barn's door.

3) The size ratio of 35mm to 16mm is constant, therefore the 16mm film will always capture the same fraction of the 35mm image.

I hope that tells you what you need to know.

(For the sake of getting the principle across I've left out some niceties such as variations in aperture size (Super-16, Super-35, Academy, etc.) and things like the overall size of the projected image, which might make a lens designed for a 16mm camera fail to project an image large enough to fill a 35mm frame, resulting in vignetting.)

I imagine that the original confusion arose because people often say "focal length" when they mean "angle of view." So when you mount a prime lens intended for a 35mm camera on a 16mm camera, its focal length stays the same... but the resulting angle of view gets narrower.

Dan Drasin
Producer/DP
Marin County, CA

Jeff Kreines writes :

>Sometimes, with a lens that casts too large a cone of light, and isn't >masked, you'll get light bouncing off parts of the camera that light >doesn't normally strike, and it can either lower contrast or introduce <artefacts.

And this is why the Optex lens mount adapter for using Nikon 35mm still lenses on an Aaton has a small rear pupil with the inside painted matte black. I've also seen on some converted Contax lenses a metal disc that limits the exit pupil of the lens. My Contax lenses do not have this and have never been a problem.

Mitch Gross
NYC DP

Mitch Gross wrote :

>I really recommend every DP pay a visit to the back room at their local >rental house and take a look at some lenses on a projector. So many >characteristics...become instantly visible and clear when projected in >front of you.

I would back that firmly. Last September when I had a problem with flare on a Canon 8-64 (or was it the 7-63, have to look at my notes) had checked for 4 of these in the optics room of the rental place and the differences within the same make and type of lenses was just unbelievable. Fall off in the corners, tracking, breathing, definition of the horizontal lines vs vertical lines. Amazing the differences.

This becomes even more visible with not so young lenses and rental ones. Especially in the 16 mm size as far as I was told 16mm lenses no longer are being developed for economical reasons. It is worth to pay a visit and see for oneself these tests.

Regards
Emmanuel from Munich

Interestingly enough a different question was asked on how to calculate the angle of view for a 2/3 chip camera. Same Issue. I provided a quick little flash app that lets you calculate this.

http://bretlanius.com/flash/angle_of_View.html

and the reverse option to get lens for given angle of view

http://bretlanius.com/flash/focal_from_angle.html

I will likely package them up a little nicer when time permits

Bret Lanius

Dan Drasin writes :

>1) A lens of X focal length lens will always project an image of the barn >at Y size on the image (film) plane.

>2) 16mm film, being smaller than 35mm, receives a smaller portion of >that projected image. So the 35mm frame might include the whole barn, >but the 16mm frame will include only the barn's door.

Reply :

So to sum up, lenses are the same whether they’re fitted to a 16mm or 35 mm camera. 14mm is still a 14mm, no matter if there is more glass in a larger barrel to suit the size of camera. Its the film were ultimately exposing so we compensate with a wider lens...to open up the space for the smaller area of neg. Simple. Sorry bout that. Hope I'm following. Feel free to kick me when I'm down.

Chris Sargent
Dir/DP
Toronto

Dan Drasin wrote :

>2) 16mm film, being smaller than 35mm, receives a smaller portion of >that projected image. So the 35mm frame might include the whole barn, >but the 16mm frame will include only the barn's door.

I'm going to assume here that the change from 35mm to 16mm did nothing to change the relative "distortion" of the barn door. If you shoot a person in close up on a 24mm lens in 35mm format their nose will seem larger than it would to the human eye. (As an aside, this is what I think people mean when they say a 40mm-ish lens in 35mm format approximates what the human eye will see...the distortion of and relationship between objects will be about the same as what we see normally).

Now if you try to shoot the same close up shot in 16mm you would need to step back a bit to get the same elements in the shot, no? But what if you couldn't because of a wall behind you? You'd have to change to a wider lens. Having changed to a wider lens the person's nose would seem even larger by comparison with the rest of their face.

Would it be fair-ish to say that if one is shooting in closed quarters, the 35mm format is a better choice as far as minimizing distortion?

Piotr Jagninski
Gaffer / NYC

Piotr Jagninski wrote :

>...If you shoot a person in close up on a 24mm lens in 35mm format >their nose will seem larger than it would to the human eye...

You're a bit confused here. Perspective is determined only by distance, not the lens. The wide angle lens simply allows you to shoot closer and still get the object in the frame. So, for example, if you shoot a person CU with a 24mm lens on 35 still camera and compare it with another shot made from the SAME distance with a 50mm lens, the perspective will be the same. The difference will be that with the 50mm you couldn't cover as much of the subject, but what you did get would have identical perspective.

>...Now if you try to shoot the same close up shot in 16mm you would >need to step back a bit to get the same elements in the shot, no?

No, you change to a shorter lens that has the same proportionate focal length. If on the 35 mp camera you used a 40mm lens, on a 16mm film camera you'd use a 16mm lens. Both cameras would see the same angle of view from the same distance, yielding the same perspective. (Assuming full aperture, 1:33.) The math: diagonal of the 35mm full aperture is 31mm. 40mm equals 1.29 x 31. Diagonal of the 16mm aperture is 12.5mm. 12.5 x 1.29 = 16.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

>you would need to step back a bit to get the same elements in the shot, >no? But what if you couldn't because of a wall behind you? You'd have >to change to a wider lens.

Wade Ramsey writes :

>No, you change to a shorter lens that has the same proportionate focal >length.

In this particular context a wider lens and a lens of shorter focal length would be the same thing. All else being equal, if you're backed up against a wall you zoom out or use a wider (=shorter focal-length) lens. Or am I missing something?

Dan Drasin
Producer/DP
Marin County, CA

If we're not too overwhelmed by this discussion of "normal"...I'd like to add that I thought that "normal" had more to do with magnification and not so much angle of view. This is what I remember from studying pin hole photography.

This can be demonstrated with a view camera. If you look at the back focusing plate or ground glass on a 5x7 or 8x10 view camera the view or size of objects provided by the "normal" lens will be the same (to your eye) if you move the camera aside.

But now... as I think about this I don't know how it applies to 16 or 35, but you have to admit it sounds pretty good and anyway somebody can use this to take this discussion further... if anybody wants to.

Edwin Myers
Atlanta dp

Dan Drasin wrote :

>In this particular context a wider lens and a lens of shorter focal length >would be the same thing. All else being equal, if you're backed up >against a wall you zoom out or use a wider (=shorter focal-length) lens.

No, in this context they aren't. A wide angle lens is a lens whose focal length is shorter than the normal lens for that format. In this instance we're talking about changing formats and using a lens that is proportionately the same, so their fields of view are identical. One is not wider than the other. But the 16mm camera lens is shorter than the 35mm camera lens. (In the example that was quoted, both cameras were using slightly wide lenses, but neither was wider than the other on its respective format, so calling the shorter one a wide angle lens in contrast to the other is misleading.)

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

Dan Drasin writes :

>DD : In this particular context a wider lens and a lens of shorter focal >length would be the same thing. All else being equal, if you're backed >up against a wall you zoom out or use a wider (=shorter focal-length) >lens. Or am I missing something?

Wade Ramsey writes :

>WR : No, in this context they aren't. A wide angle lens is a lens whose >focal length is shorter than the normal lens for that format. In this >instance we're talking about changing formats and using a lens that is >proportionately the same, so their fields of view are identical. One is not >wider than the other. But the 16mm camera lens is shorter than the >35mm camera lens.

And now a word on behalf of rental houses everywhere. Pretend you're a busy rental guy and a very busy producer calls up to ask you that question and wants a simple answer immediately -- one that he can understand, when he doesn't understand any or most of the terms -- so he can pass the answer on to his DP, who for some reason doesn't know the answer and cannot, or will not, call the rental house directly.

So the producer then tells the DP what he thinks the rental guy told him as the producer understood or misunderstood it. The question then gets posted here and the rental guy gets blamed.

Just because someone understands something, it doesn't mean he or she can explain it clearly. As evidence, I could cite any number of computer manuals.

In any event, if it is extremely difficult for experienced professionals to put these essentially visual concepts into words so that other experienced professionals can understand them clearly, imagine what it's like when the people involved are not very experienced and in a hurry and get the info second or third hand.

One other thing to keep in mind: while we might like people to think otherwise, rental companies are not repositories of all knowledge relating to cinematography. If they were, we wouldn't need cml -- and Geoff Boyle would have to find something else to do to keep himself up at night.

Brian Heller
IA 600 DP

Edwin Myers writes :

>If you look at the back focusing plate or ground glass on a 5x7 or 8x10 >view camera the view or size of objects provided by the "normal" lens >will be the same (to your eye) if you move the camera aside.

That would be true only if you'd held the ground glass at a particular distance from your eye. But what distance would that be? The same as the focal length of the normal lens? Closer? Farther? Arm's length? ???

Dan Drasin
Producer/DP
Marin County, CA

Dan Drasin writes :

>That would be true only if you'd held the ground glass at a particular >distance from your eye. But what distance would that be? The same as >the focal length of the normal lens? Closer? Farther? Arm's length? ???

Normal distance, of course.

Brian Heller
IA 600 DP

The idea of "normal" or "standard" in the case of still photography assumes that a "standard" sized print will subtend the same angle of view, and show the same perspective, as the original image. .

For prints & enlargements, it's assumed that you would be using viewing at normal reading distance (darn it there's that word 'normal' again - say around 16-18 inches or 40-45cm). I guess the same would be assumed when looking at the ground glass plate in a plate camera.

The geometry turns out to show that the "normal" taking lens in such a situation would have the same focal distance as the viewing distance.

By this argument you need to examine a 35mm negative shot with a 50mm lens from a distance of 50mm (not so easy) - or blow it up by a factor of 8 so the print subtends the same angle at a distance of 8 times as far - or 40cm, the normal reading distance. This would give you a print of 192mm x 288mm - about 7 1/2" x 11", twice as big as the "normal" postcard-sized print.

But the same argument leads us to a 400mm lens for a plate camera - seems far too long. Typically I'd have expected about a 250mm lens for a whole-plate camera.

So I guess the whole theory is shot!

Dominic Case
Atlab Australia

Dominic Case wrote :

>...But the same argument leads us to a 400mm lens for a plate camera - >seems far too long. Typically I'd have expected about a 250mm lens for >a whole-plate camera.

Good grief, Dominic! Do they still use the term "whole plate" in Oz? That's 19th Cent. terminology! But then...

If I recall the history, a whole plate would be something in the vicinity of 20cm x 25cm or so (about 8" x 10", to us colonials.) The normal lens for that size format isn't 400mm, it's 325mm, about 13 inches. You can easily view a contact print from that format and you'll probably automatically hold it about 30 cm to 40 cm (12" to 16") away from your eye. So you're going to naturally view it at about the focal length of the taking lens, the theory still holds.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

Brian Heller wrote :

>...In any event, if it is extremely difficult for experienced professionals to >put these essentially visual concepts into words so that other >experienced professionals can understand them clearly, imagine what >it's like when the people involved are not very experienced and in a >hurry and get the info second or third hand...

I'm know Brian isn't defending ignorance of equipment and processes on the part of anyone working as a professional, but rather expressing the frustrations of a rental guy trying to convey technical info to some intermediary who may have all the techno-savvy of his 6 yr. old daughter. It's obviously difficult when you have to communicate it to an unqualified person. You don't explain all this to the intermediary, you tell him/her, "use this lens." It may well be that this person can't even adequately describe the problem you are to help him solve.

But here we're discussing the matters with professionals, the guys and gals who are directly responsible for producing the results. They're the ones who, if they haven't had occasion to learn it before, come to CML to fill in the gaps in their knowledge. Understanding the theory makes it much easier to solve future problems that differ somewhat from the one at hand.

Anyone working with cameras needs to understand the relationship of the lens focal length to the camera's format and how that in turn relates to scene coverage. It's more vital than ever before, because we are now dealing with S-16, 35 in several iterations, 2/3", 1 /2" , 1/3" and even smaller video. We have more formats than ever before and in many cases we're called on to choose between them for a project. We'd better know how that impacts lens choices.

And don't send a dodo to the rental house (even in Oz!) That's like sending my totally computer challenged wife to Microsoft for help.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

Dan Drasin wrote :

>That would be true only if you'd held the ground glass at a particular >distance from your eye. But what distance would that be? The same as >the focal length of the normal lens? Closer? Farther? Arm's length? ???

I think that will be true if you view the ground glass at the focal length of the lens you're using. You can do that with large format cameras. With shorter lenses you'd view it closer, ultimately needing a magnifying glass to focus on the close viewing distance; longer lenses, farther away from the ground glass.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614