Super 35mm Crop Factor and a "Normal" lens.

[Mitch Gross]

The short answer is about a 35mm. But here's the other answer:


There is no such this as a Normal lens.


Ah, that felt good. A normal lens is based on relative perspective and has to do with the way in which we physically position ourselves relative to the field of view our brains pay attention to. The human vision with two eyes can see about 120 degrees horizontal field of view. That's a crazy wide angle, around a 12mm or so in Super-35 (don't trust me on that, it's a guess off the top of my head). But our brains zero in to mentally pay attention to only a small part of that field of view and to discard the rest most of the time.

Here come some grossly stereotypical examples; please don't get offended. If I was a reserved Finnish man, I might greet someone and hold a conversation from four feet away, with my brain concentrating on a relatively narrow field of view at an angle roughly equivalent to a 50mm in S-35. If I was a passionate Italian then I might converse animatedly at only two feet away, causing my brain to concentrate on a field of view equivalent to 25mm in S-35.

Now try this: If I wanted to shoot a movie with an intimate feel, I might choose a wide lens as my "normal" and move the camera closer. If my movie was a broad comedy, I'd likely choose a longer lens as my "normal."


"Normal" is a frame of reference, a rule of thumb. There is no absolute because we as humans are not absolutes.

BTW, this is the kind of stuff I teach in my "How to Choose Yor Lens" class at AbelCine. The next class is in NY next Monday the 11th.

training.abelcine.com

 

[Barry_Green]

You want a 35mm lens to get close to the look Hitchcock favored.

But that's wrong. Hitchcock was using a film format that's for all intents and purposes exactly the same size (width-wise) as the FS100. So if you want the look he wanted, then you'd use a 50mm.

This is due to the difference in frame/sensor size between the format Hitchcock would have used (most certainly full-frame 35mm film - either unmatted/"Academy" or matted/"Flat" or anamorphic/"Scope") - and today's Super 35 (film) and APS-C (Photo, and now, video) sensors.

There is no difference. Well, none of substance. There's pretty much no such thing as "full-frame 35mm film" when used for motion pictures. The standard of the day was 22mm-wide Academy-aperture, which is basically exactly the same as the 23.6mm wide of today's digital S35 sensors.

There, that wasn't so hard, was it guys?

Turns out it was, because your point of reference was wrong. If you want to say that a 35mm lens works on 35mm movie film the same way as a 50mm lens works on 35mm still film, you'd have been right. But Hitchcock was discussing the way a 50mm lens performs on 35mm movie film. And for that comparable look on today's digital S35 cameras, you'd want a 50mm. Or probably a 51mm if you wanted to be exact.

Why do we have to get so bent out of shape and extreme any time anyone mentions "crop factor"?

Because all it does is confuse people. Which is why we have hundreds of threads on it. And it's based on an artificial concept, which is that somehow SLR frame sizes are "the standard" or have anything whatsoever to do with motion cinematography.

 

[Steve R]

its subjective to the individual.

For me a 35mm focal length gives me a normal field of view. I also use 28mm for this purpose as well.

Agreed. When I shot comparisons against real frames from scenes in films I was trying to replicate, the ideal was in between; It depends upon so many factors w.r.t. the shot, of course - but in general I'd reach for (or first purchase) a 35mm for Normal use.

 

[Barry_Green]

The human vision with two eyes can see about 120 degrees horizontal field of view.

The average person can certainly perceive way more than that. It's more like 160 degrees or even more. Just stick your arms out straight, and stare straight ahead, then bring your arms in until you can perceive them; you don't have to move your arms very far at all before you can see them moving into your field of view.

120 degrees is probably about right for one eye, but not for both.

That's a crazy wide angle, around a 12mm or so in Super-35 (don't trust me on that, it's a guess off the top of my head).

A lot wider than that; 12mm in S35 only delivers about 100 degrees. You'd need about an 8mm before you started even getting close.

That's why I say that a "normal" lens will render the perspective normally, but won't in any way approximate the field of view. You pretty much can't get a field of view that matches human vision, for many reasons, not the least of which are the ones you stated about the way our vision works.

"Normal" is a frame of reference, a rule of thumb. There is no absolute because we as humans are not absolutes.

In theory and in the examples that you reference, probably. But in the general discussion of what is "normal", is it not generally accepted that the idea of a "normal" lens is one that renders perspective comparable to the way humans see perspective? And in that context, a "normal" is usually said to be about 50mm for a 35mm stills camera, and about 35mm for a cine camera.

 

[Steve R]

Because all it does is confuse people. Which is why we have hundreds of threads on it. And it's based on an artificial concept, which is that somehow SLR frame sizes are "the standard" or have anything whatsoever to do with motion cinematography.

I completely agree that comparison with 35mm photography formats is wrong (and you're right about frame size of Academy - which Hitchcock was likely using).

But I don't agree with people jumping all over each other when they mention "Crop Factor" at all - when the spirit and gist of what they're usually asking is "What lens do I need on format X to replicate this kind of shot on format Y".

 

[Steve R]

And in that context, a "normal" is usually said to be about 50mm for a 35mm stills camera, and about 35mm for a cine camera.

Yay! I think that's all he was really asking.

I think it was the "Hitchcock's favorite" that muddied it a bit...

 

[Barry_Green]

when the spirit and gist of what they're usually asking is "What lens do I need on format X to replicate this kind of shot on format Y".

Well, you are correct. And if people would just get used to the idea that "35mm" is a "normal" in cinematography, and that wider-than-35mm is considered wide-angle, and longer-than-35mm is considered telephoto, then -- we wouldn't go chasing "crop factors" and all that.

The crop factor causes problems because people are out there thinking that a 35mm lens is a wide-angle (when it is not -- it's dependent on the format!) but if they use a 35mm, then all their faces will look distorted. And that's simply not true! But those who insist on comparing cinematography to stills photography are setting themselves up for confusion.

There are people who think short focal-length lenses "distort" and have "bad perspective", and that longer focal-length lenses are ideal, so they try to avoid a 35mm and instead cling to an 85mm. But in cinematography, the 35mm is "normal" with zero distortion, and the 85mm would result in extreme compression and flattening. You'd get more pleasing portraiture out of a 50mm lens in cinema, than you would out of an 85mm.

So when people invoke the "crop factor", their initial reasoning is just plain faulty -- if understandable. Yes we all understand what they mean, but they shouldn't be taught to continue that connotation because it leads to incorrect conclusions.

A 28mm lens is not a wide-angle lens. It's a 28mm lens. On a DVX100, that would be considered a telephoto. In video, we pretty much never ever mentioned, brought up, or considered the "crop factor", because we all knew that that was irrelevant and basically nonsense. I just wish we could get to that same place with cinematography.

In 35/S35 cinema, a 30mm to 35mm lens is considered "normal". Shorter than that is wide-angle. Longer than that is telephoto. And it does not matter one jot, nor tittle, nor whistle nor nit, what the lens looks like on a "full frame" stills camera...

 

[Barry_Green]

I think it was the "Hitchcock's favorite" that muddied it a bit...

Agreed 100%.

 

[Steve R]

The short answer is about a 35mm. But here's the other answer:


There is no such this as a Normal lens.


Ah, that felt good. A normal lens is based on relative perspective and has to do with the way in which we physically position ourselves relative to the field of view our brains pay attention to. The human vision with two eyes can see about 120 degrees horizontal field of view. That's a crazy wide angle, around a 12mm or so in Super-35 (don't trust me on that, it's a guess off the top of my head). But our brains zero in to mentally pay attention to only a small part of that field of view and to discard the rest most of the time.

Here come some grossly stereotypical examples; please don't get offended. If I was a reserved Finnish man, I might greet someone and hold a conversation from four feet away, with my brain concentrating on a relatively narrow field of view at an angle roughly equivalent to a 50mm in S-35. If I was a passionate Italian then I might converse animatedly at only two feet away, causing my brain to concentrate on a field of view equivalent to 25mm in S-35.

Now try this: If I wanted to shoot a movie with an intimate feel, I might choose a wide lens as my "normal" and move the camera closer. If my movie was a broad comedy, I'd likely choose a longer lens as my "normal."


"Normal" is a frame of reference, a rule of thumb. There is no absolute because we as humans are not absolutes.

BTW, this is the kind of stuff I teach in my "How to Choose Yor Lens" class at AbelCine. The next class is in NY next Monday the 11th.

training.abelcine.com

So, is there a better term (or do we need a new term) for lenses that fall between wide and telephoto? You know, for general discussion, lens charts, marketing etc.

I'm actually serious. I get what you are saying, and it makes sense (i.e. "wide can be normal").

So what should we call that focal length territory that, you know, we're all talking about?

 

[Mitch Gross]

But in the general discussion of what is "normal", is it not generally accepted that the idea of a "normal" lens is one that renders perspective comparable to the way humans see perspective? And in that context, a "normal" is usually said to be about 50mm for a 35mm stills camera, and about 35mm for a cine camera.

If I stand three inches away from you then the rendering of perspective will be much like an extreme wide angle lens. If I stand 20 feet away and concentrate on just your face then the perspective will be much like that of a telephoto lens. "Normal' is based on what one would consider a "normal" distance from an object relative to the field of view in which we would "normally" concentrate. If you're a Seinfeld "close talker" then you see the world with a wide angle lens.

 

[J Davis]

Earlier I said 35mm and 28mm but for some interiors I've used 24mm because it felt right

But sometimes you got to cheat.

 

[cpc]

A few quick comments. I don't have time to delve into details in the moment.

1) Hitchcock shot a fair amount of movies in VistaVision, which is close to stills Full Frame (technically it is smaller, because it uses a rather cropped projection aperture). No idea if this has anything to do with his "favorite lens" being 50mm.

2) Squarish aspect ratios like the Academy ratio are more straightforward and imply a single important object in the frame. They favor slightly longer lenses because these help isolate subject matter and focus on the actors. The Academy ratio was a glamour ratio for a reason.

3) Viewing distance has much to do with perspective and "normality". A long lens shot will appear "normal" if viewed from the appropraite distance further back. The "diagonal of the frame" rule for a normal lens has been "invented" for the viewing distance for prints. Which is obviously inappropriate for cinema.


(Nirv, you are always too kind. )

 

[David W. Jones]

In a book by Herb Coleman, he tells a story about them having to reshoot scenes for Vertigo using a 35mm lens because of space restrictions of the set and Hitchcock giving them a hard time for not using the 50mm lens he likes so much.

Steve, some of us tend to feel strongly about the whole crop factor thing because we have been shooting 35mm film for a very long time, and now all of a sudden we are having this full frame 35 still format rammed down our throats as the motion standard which all other frame sizes must be compared to.

All the Best!

Dave

 

[cpc]

In a book by Herb Coleman, he tells a story about them having to reshoot scenes for Vertigo using a 35mm lens because of space restrictions of the set and Hitchcock giving them a hard time for not using the 50mm lens he likes so much.

Well, Vertigo was in VistaVision, FWIW.

 

[David W. Jones]

Here is a cool VistaVision Q & A from the day... http://www.widescreenmuseum.com/widescreen/vvbook2.htm

Since the best picture composition and the best theatre presentation will be obtained in the aspect ratio of 1.85/1, this ratio is recommended by the Paramount Studio technical staff.

 

[cpc]

Yes, most VistaVision films were printed down to vertical 4-perf 35mm and shown at 1.66:1 or 1.85:1. Some were contact printed on 8-perf horizontal but still shown with 1.85:1 projection aprture.
But as the angle of view depends on capture frame size only and not print film frame size, it was still similar to full frame stills 35mm, and wider than vertical 35mm.

 

[thxdave]

Oh no....we're going to talk about Vistavision? Let's see....it runs through the camera horizontally when the negative is exposed....and its normal lens is....what? A 50mm? Just curious. I'm praying this thread doesn't go off onto a "wide angles have more depth of field than normal lenses" tangent.

 

[Grug]

Well, Vertigo was in VistaVision, FWIW.

As was North by Northwest.

As someone who came into 35mm motion-picture (video) capture from 135 still photography (full-frame). Firstly with 35mm adapters (which emerged just as I was finishing uni) and then with DSLRs and large-sensor video cameras - I've actually always found the whole crop/equivalent jargon incredibly helpful (though I suppose in many ways I was the target market for that).

I grew up with 50mm lenses providing a 'normal' perspective. 28mm lenses providing a wide perspective. 85mm-135mm lenses making a nice mild telephoto perspective for portraiture, and 200mm being a proper telephoto lens.

As such I never really thought too much about the focal lengths themselves, merely the perspective they'd give me (wide, normal, telephoto). So moving into a smaller image format like S35mm (and soon the oddly sized BMC), having a simple 'crop factor' that I could apply to the various focal lengths I had available, made it very easy to find my reference points again. So on S35mm 18mm became my 'wide', 35mm became my 'normal', and 50-85mm became my portrait telephotos.

When I consider every other focal length, I simply choose them in reference to those three marking points - wide, normal, tele.

Obviously a lot of people get caught up and frustrated by the technicalities of it all, but I suspect most people simply see these things in the same way as I do - wide, normal and telephoto - and simply want to know what the equivalent perspective will be with lenses on any smaller or larger format.

 

[alaskacameradude]

I think the whole 'crop' thing is brought on by one main event.....still(DSLR) shooters who are moving to shooting video.
Because for me....I could care less that a F3 or FS100 or C300 has a '1.6 crop'. It does? Compared to what? Oh, compared
to a 5dMKII? Don't care. That's not a real motion camera, so I've never shot with one. So the people that this matters
too, are those who are using the 5D Mark II as a REFERENCE POINT! See, that's all this is, is a reference point for people
who are used to a full frame still camera and want to 'base' everything else off that reference point. For those of us
who are not still photographers and never shot anything with a full frame DSLR, this means nothing. I know what a 50mm
or 35mm looks like on a F3. I have no clue what they look like on a 5D and don't really care that much to be honest.
And who decided that the 'full frame' still cameras should be the reference point? Maybe there are medium format photographers
somewhere saying that the 5D Mark II has a '1.5 crop factor'. All this 'crop factor' nonsense is just a frame of reference.
Now I understand this can help people who primarily shot 5d's understand that a 35mm on a FS100 would have a similar FOV
as a 50mm on their 5D Mark II. But for people who haven't shot with the 5d Mark II it is just confusing things and creating
a bunch of crazy talk from these 'experts'. I had a DSLR fanboy telling me yesterday that the 35mm I had on my FS100 'became'
a 50mm. Really? How did it do that, some kind of crazy magic up in that lens that I didn't know about? Of course, this
was the same dude who cranked his shutter speed up to about 1/250000000000000 of a second to get correct exposure outside,
because that's what still shooters do, and then was wondering why the motion looked all stu...stu....stutt....stuttery.
Crazy how that works.

 

[moldcad]

Like you, I never used a full-frame DSLR for filming - but the fact remains that in most lens specs, their focal values are expressed in both their "native" and equivalent 35mm terms...

For that reason, i never even remembered the focal length of my EX1 lens other than "from some 30-ish mm up to x14 that"

So the full-frame stills 35mm is in fact serving as a common platform to compare various lenses on various sensor sizes - and let's leave it that way.