Ask David Mullen ANYTHING

[benfilm]

Great topical information, thank you very much to all.

I will probably do some more hesitating for a few days before buying it.

 

[benfilm]

1) Something I find confusing: when people talk about focal lengths used in movies, they indifferently take examples from anamorphic and spherical movies. But there is a 2x factor involved: is there an implicit convention here?

2) The rule "a lens of 50mm is about the human eye" comes from 35mm still photography, but if I am not mistaken it is false for most movies because it doesn't apply to spherical focal lengths: it would give a horizontal angle of view of 23.7°, which is obviously much narrower than the human eye. Applied to anamorphic focal lengths it computes to 47.5°, which seems reasonable (applied to 35mm still photography it gives 40°).

Again, are there any implicit conventions when people say "50mm is the human eye"?

 

[David Mullen ASC]

There is a difference between matching field of view to human vision and matching perspective. Human vision has quite a wide view -- the Cinerama format, for example, used a 145 degree field of view to create an immersive experience on the big screen; IMAX often uses very wide-angle lenses. In both cases, the image on the very large screen combined with the very wide view helps stimulate the peripheral vision of the viewer as happens in real life; you could say in that case that the "normal" view is in the center of the big screen and the wider-angle edges are just to engage peripheral vision.

A "normal" lens in film is not one that matches human field of view, it's one that does not either enlarge or shrink the size of the subject when comparing the view through the viewfinder to the view with your eyes standing next to the camera. Essentially it maintains a normal perspective to the scene, neither wide angle or telephoto. But I don't really believe in the concept of a "normal" lens anyway.

A 50mm anamorphic lens has the field of view of a 50mm spherical lens vertically but a 25mm spherical lens horizontally. Thus overall it "feels" more wide-angle than a 50mm spherical lens. With a 50mm anamorphic, you do have something that seems closer to human vision, i.e. a "normal" degree of enlargement/perspective but increased horizontal view.

 

[Shawn Nelson]

A 50mm anamorphic lens has the field of view of a 50mm spherical lens vertically but a 25mm spherical lens horizontally. Thus overall it "feels" more wide-angle than a 50mm spherical lens. With a 50mm anamorphic, you do have something that seems closer to human vision, i.e. a "normal" degree of enlargement/perspective but increased horizontal view.

Then why don't people appear "squished", flattened, or otherwise stretched horizontally when shot in anamorphic?

 

[Dominic Jones]

On the neg/prints/etc they do - you use a similar lens on the projector to "unsquish" the image. This is what allows you to store a 2.4:1 image within the area allowed for sound aperture prints (the actual ratio on the neg or print is 1.2:1, slightly more square than the 1.33:1 Academy aperture it sits within).

It was designed to allow for very wide formats without sacrificing too much real-estate (and therefore resolution, of course) on the film...

Slightly incidentally, you can still observe some horizontal compression on anamorphically shot films in some cases, particularly in the background of shots that employ a very close focus - but that's a factor of slightly less than optimal lens design (or to be more accurate, compromising between perfect optics and the desire for greater focus range), rather than an inherent flaw in the concept.

 

[David Mullen ASC]

On the neg/prints/etc they do - you use a similar lens on the projector to "unsquish" the image.

Yes, and in a video transfer, you electronically unsqueeze the image.

4-perf 35mm theatrical prints come in two types: "flat" (spherical) for matting in the projector to widescreen (usually 1.85), and "scope" (anamorphic) with a 2X image squeeze (and a 1.20 projector gate) that is unstretched to 2.40 by the anamorphic projector lens.

 

[benfilm]

There is a difference between matching field of view to human vision and matching perspective.

If I understand things correctly, field of view is the only factor.

When I stand next to the camera, the perspective (in the sense of compression of space, the relative sizes of objects at different distances) does not depend on the lens at all. In other words, standing next to the camera if I take a photo of a group of objects arranged at different depths (eg a big crowd), with a very telephoto lens, and then with a wide-angle photo, the relative sizes of these objects will be exactly the same in both photos. If I crop the wide-angle photo with a pair of scissors, I get the exact same photo, only smaller.

Actually my question was very practical: in a previous thread (http://www.reduser.net/forum/showthread.php?t=6938&page=3) you said "Psycho was mostly shot with a 50mm lens. Hitchcock did not like distorted perspectives too much."

That's the kind of statement I don't get. Did you mean 50mm in 35mm still photography equivalent, or the actual focal length of the spherical lens? Psycho was shot with spherical lenses, so 50mm computes to 23.7° horizontal field of view, which feels much narrower than the eye.

 

[David Mullen ASC]

If I understand things correctly, field of view is the only factor.

When I stand next to the camera, the perspective (in the sense of compression of space, the relative sizes of objects at different distances) does not depend on the lens at all. In other words, standing next to the camera if I take a photo of a group of objects arranged at different depths (eg a big crowd), with a very telephoto lens, and then with a wide-angle photo, the relative sizes of these objects will be exactly the same in both photos. If I crop the wide-angle photo with a pair of scissors, I get the exact same photo, only smaller.

Actually my question was very practical: in a previous thread (http://www.reduser.net/forum/showthread.php?t=6938&page=3) you said "Psycho was mostly shot with a 50mm lens. Hitchcock did not like distorted perspectives too much."

That's the kind of statement I don't get. Did you mean 50mm in 35mm still photography equivalent, or the actual focal length of the spherical lens? Psycho was shot with spherical lenses, so 50mm computes to 23.7° horizontal field of view, which feels much narrower than the eye.

Well, that's why you are confused, because "normal" lenses don't match field of view of human vision.

Human vision has quite a wide-angle field of view, but we don't consider wide-angle lenses to be "normal" lenses, we consider them to be wide-angle lenses.

Hitchcock and Ozu preferred the 50mm lens for the perspective, not the field of view, though your notion of perspective may be different than mine. Perspective in that sizes and distances of objects seem undistorted, neither stretched by a wide-angle or compressed as with a telephoto.

Now you have to remember though that modern widescreen formats like 1.85 are cropped down from the old 1.37 Academy and thus lose some vertical field of view, so a 50mm feels slightly tighter today than it did in the 1940's. Of course, "Psycho" was a 1960's movie but Hitchcock's experience was with pre-widescreen formats.

Whenever you get into discussions of what "normal" is, you fall into personal opinion.

Roman Polanski thought that wide-angle lenses were "normal" to him and they shot "Chinatown" almost entirely on a 40mm anamorphic lens because the DP and him felt it was close to a "normal" perspective, though some would find that to be a wide-angle lens.

Generally in modern 35mm spherical movie photography, the "normal" range is anywhere from 35mm to 65mm-ish, maybe even 75mm, in terms of presenting an undistorted perspective on reality. But again, I'm not talking about matching human vision's field of view, which is quite wide-angle.

If you define "normal" as the length of the diagonal of the frame in millimeters, I think the standard 1.85 4-perf 35mm frame is more like 28mm or 35mm (not having done the math) compared to a 1.50 8-perf 35mm still camera frame.

It's all rather academic -- you use the lenses that give you the look you like.

 

[vincelucero]

this is the best thread ever. thanks for your time david.

 

[benfilm]

If you define "normal" as the length of the diagonal of the frame in millimeters, I think the standard 1.85 4-perf 35mm frame is more like 28mm or 35mm (not having done the math) compared to a 1.50 8-perf 35mm still camera frame.

According to http://en.wikipedia.org/wiki/35mm_film#Technical_specifications, the projector aperture for 1.85 is 21mm x 11mm, so the diagonal is 23.7mm (nothing to do with the 23.7° from before): with the rule "normal focal length = diagonal" a normal lens would be 23.7mm, which feels small and that was why I was asking the question in the first place (this rule computes to "normal lens = 53.1° angle of view"). Same for the projected Academy diagonal: 25.8mm, feels small. But the diagonal of unsqueezed anamorphic is 45.4mm (43.2mm for still 35mm), which is closer to the 50mm focal lengths we expect.

But since, as you say, in actual practice a lot of lenses (not just around 50mm) are going to feel more or less "normal" in the final image, I won't worry about that 50mm value anymore.

About that perspective thing, I was just making the point that, although it may feel counterintuitive, perspective (which is, as you said, the relative sizes of objects at different distances) only depends on your position relative to the objects, not at all on the lens you use (all this becomes incorrect in macrophotography because subject-object distances become comparable to focal lengths).

Contrary to basic intuition, when you look at two people who are at different distances from you, if the closest one is exactly two times as big as the furthest one, then as long as you don't move, whatever you use (your eye, an extreme wide-angle, a long telephoto -- as long as the two people remain in the frame), if you look in the direction of the two people, the closest one is always going to remain exactly twice as big as the furthest one. Although in wide-angle you are going to see a lot more than just the two people.

But again, it works only if you don't move. In practice, you move; you walk further away and increase the focal length, so in that case the sizes of the two people will be closer, that is, perspective changes.

The point is mostly theoretical, but still, I find it interesting to note that, strictly speaking, perspective depends only on position, not on the lens: the lens only changes the field of view, not the perspective (again, with the definition that perspective is the ratio of the sizes of objects at different distances, which is the correct definition). We associate long lenses with compressed perspective only because we move away when we use long lenses: in reality compressed perspective is not a property of long lenses -- only narrow field of view is. It sounds obvious when said differently: a long lens just takes part of an image and enlarges it uniformly, it doesn't affect perspective in any way.

 

[Jens Jakob Thorsen]

I tend to feel that a 50mm lens on a 36x24mm still is a wee too long for "normal" human perception. it feel more like a 46-48mm.
On super 35mm film the 32 feels very close to that "distortionless" state that a "normal" lens should achieve(a 35mm feels a little long for me)
My 3 favourite lenses are the 28mm,40mm and the 65mm on super35.
Certainly nobody would claim that the 40mm anamorphic is even close to normal as are talking close to a 20mm spherical.
I think I remeber reading about Polanski having big discussion with John Alonzo(an underestimated DP in my opinion, who also did wonderfull work with Mike figgis in "Internal Affairs","Scarface" and one of my favorite films "Harold and Maude")about using the 40mm as the main lens. This was especially a n issue when shootin medium closeups and closeups of Faye Dunnaway. As allways the genius filmmaker Roman Polansky prevailed and proved that his lens dogma for this film worked for the story.

 

[Jens Jakob Thorsen]

On another note I would like to hear your thougths on this subject that concerns backflare from the OLPfilter
www.reduser.net/forum/showthread.php?p=157675&posted=1#post157675

 

[Shawn Nelson]

David, have you seen the movie "Diving Bell and the Butterfly"? I am curious what your thoughts on it are. I watched it on Saturday and was shocked at just how subjective you could really push a movie. Never would I have thought that repeatedly breaking the fourth wall could work so well for a serious narrative fiction, neither could i think that simply blurring the screen could make me want to cry. I was surprised it was done by Janusz, as it didn't feel like his other work, no lighting in the shots called attention to themselves.

 

[David Mullen ASC]

I thought it was a great work of cinematography, exactly what cinematography is all about. I was amazed that such a restrictive style could be so expressive and dramatically involving. Yes, the lighting is natural; it would be hard to justify something more theatrical and stylized (except for the character's fantasies.)

 

[Davide B.]

Hey David,

This is my first time posting on reduser but I've been visiting the site regularly ever since this thread started in the off topic forum. It's up there with Painting with Light as one of my favorite places to look for techniques and advice on cinematography. (This gets a nod as I don't have to check it out from the library every time I want to read it).

I'm currently prepping for a shoot and was hoping to get yours, and anyone else's on this forums advice. The scene takes place in Afghanistan, but I'm going to have to shoot it in or around NYC. It's a medium-wide (28mm or so) static shot of archaeologists in the desert stacking up crates to be loaded on a truck. The perspective is going to be straight on and perpendicular with the horizon.

In order to cheat it I was hoping to film it like in these pictures. The first is credited to Michael Reichman at Luminous Landscape. The other is the work of cinematographer John Alton in The American in Paris.

I figure that with the foreground silhouetted and the background a bunch of haze and swirling sand I can get the vibe of the deserts of Southern Afghanistan without actually being there. Any thoughts on how to best go about this using an indoor set? Would it help to composite in a mountainous landscape background? All help will be greatly appreciated. This is going to be shot on a DVX100.

Conversely, if anyone knows of a place around the NY metro area that could be cheated for this (maybe a sand quarry surrounded by mountains) that would be great too. Thanks!

 

[David Mullen ASC]

A hazemaker (smoke machine) and strong (warm) backlight basically, though if you also want real dust in the air, you probably have to go with something like ground walnut shells (I think that's the product) -- Fuller's Earth is no longer considered safe to breathe.

 

[dracul]

hmmm, well i feel like an idiot not seeing this thread earlier. Well, Mr Mullen, I cannot delete the thread now so please have a look at "For Mr. David Mullen Shooting Dark"

Thank you

 

[dracul]

Par bank on crane for sun?

Par bank on crane for sun?

My question is about the sunlight on the back wall. Assuming the budget was available for one of those 24 bank 6k Pars on a crane/generator would you have one of these standing by to throw in a situation like this or would you just fire a 18k off a scissor lift?

The reason I ask this is more of director flexibility. If you use the Crane it can back up more and perhaps the director wants to show a bit out the window without the crane in shot but the 18k on scissor would have to be much closer.

 

[Steven Parker]

I tend to feel that a 50mm lens on a 36x24mm still is a wee too long for "normal" human perception. it feel more like a 46-48mm.
On super 35mm film the 32 feels very close to that "distortionless" state that a "normal" lens should achieve(a 35mm feels a little long for me)
.

This is a very interesting idea...

I don't remember when, but somewhere in my filmmaking learning curve, I learned that the 50mm lens, in Academy 35mm, was, quote, "an eye-real lens." Meaning it perceives space as we humans do. Many years later I met an old writer - a beautiful man who was blacklisted back during McCarthyism and somehow stayed alive and writing anyway. He was an on-set writer for John Ford who was, to hear the writer tell it, a fan of the 50mm lens. But John Ford wore an eyepatch - he could only see out of one eye! The writer firmly believes that's why Ford's compositions are so strong - he wasn't burdened with true depth perception...

But as I grow as a cinematographer, I choose the 50mm less and less. I put it up and it feels like I couldn't make up my mind about the shot - it's an odd in-between size. For "eye-real" I'll shoot a 32mm when I can get it, a 35mm if I can't. In Academy, anyway. I have yet to shoot Super35.

But then again, it's all about the story. Maybe "eye-real" or "normal" perception is a 50mm on one movie, a 28mm on the next...

 

[dracul]

Exposure Rank For Clean Shadows

Exposure Rank For Clean Shadows

Mr. Mullen,

Could you confirm if this is an ideal way of exposing the following shot of yours.