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Student trying to understand aspect ratio


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#1 James Sheppard

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Posted 19 January 2012 - 12:43 PM

Hey everyone!

I've been browsing this website for a while and have found it very informative, but I have something I need help with.

Im currently studying film production at college, so I am a bit new to the theory side of it all, but here goes.

Basically I want someone to correct me on with this list of aspect ratios as I have brain ache trying to figure it all out.

16mm is 1:37:1
Super 16 is 1:66:1
35mm is 1:37:1
A anamorphic lens on a 35mm will produce a ratio of 2:39:1
Super 35mm? No idea,

I know super 35 has no audio track as thus provides a wider ratio without the need for a anamorphic lens. Spherical lens' are used on super 35, correct?

Super 35 is mainly 4 perf, but to save cost it can be 3 or even 2 due to the unused space top and bottom of a super 35 frame, correct?

What is the standard (if one) for cinema release? Is it 2:39:1?

Can someone also explain to me what the ratio 1:85:1 is?

Is 16:9 equivalent to 1:78:1 and 4:3 1:33:1

Help would be very helpful! :)
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#2 Brian Drysdale

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Posted 19 January 2012 - 02:56 PM

The current standard flat (non anamorphic) cinema aspect ratio is 1:85, the 2.39:1 is what would be projected using an anamorphic lens. Most films tend to be 1.85:1.

35mm can be a number of aspect ratios depending on how it's framed during production and if it is shoot with anamorphic lens or spherical lenses. There have been various aspect ratios used over the years. http://en.wikipedia....wiki/35_mm_film http://en.wikipedia....t_ratio_(image)

You can have 4 perf, 3 perf or 2 perf pull downs in the camera, but these will be converted to 4 perf for the print.

16:9 is 1.78:1, although not usually referred that way. 4:3 tends to be used in TV land, while 1.33:1 in cinema, but they're the same.
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#3 James Sheppard

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Posted 19 January 2012 - 04:07 PM

Hi Brian, that makes a little more sense now.

So if we were to look at it backwards for my benefit of understanding.

Say I want my final product to be shown 1:85, I would use a 35mm with a spherical lens?

On the other hand, say I wanted to show it in 2:39, I would use 35mm with a anamorphic lens to squeeze in more horizontal picture? If that is the case, am I correct in saying Super35 does this without the use of a anamorphic lens?
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#4 Brian Drysdale

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Posted 19 January 2012 - 04:21 PM

You would shoot 1.85:1 with a spherical lens. There are a number of methods of shooting 2.39:1, one of which is to shoot Super 35 without an anamorphic lens and do the squeeze in post for the 35mm print. Although, with digital S35 sensors, the market is developing for anamorphic lenses with less squeeze than the film anamorphic lenses.

Super 16 can be blown up to 35mm and it's usually framed for 1.85:1 for theatrical release.
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#5 Adrian Sierkowski

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Posted 19 January 2012 - 04:26 PM

Also as 1.78:1 is larger than 1.85:1 you could shoot HD (16x9/1.78:1) and with a slight crop have 1.85:1 for theatrical.
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#6 Chris Millar

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Posted 19 January 2012 - 05:12 PM

1:85 on a normal 4 perf pull down will not use the top and bottom of the frame - it's particularly wasteful in this regard, which is something that people might disregard as silly when going through the mental simulation of how it works (in an absence of information otherwise).

Scope uses the full frame in both acquisition and projection - as did 'full frame' (funny that) - but 1:85 can use 4 perf, tops and bots wasted, or 3-perf pull down acquisition - but as has been pointed out, projection is always 4 perf.

Personally, in terms of efficiency and/or elegance - I think scope is best, either that or 2 perf acquisition which is then projected in scope, of which there is precedence (less light wasted heating up an aperture plate in the projector and less film wasted in camera)

But I've only been involved with 35 filming twice, and never touched the camera - so what do I know ;)
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#7 Chris Millar

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Posted 19 January 2012 - 05:16 PM

oop, by full frame I meant academy.
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#8 Brian Drysdale

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Posted 19 January 2012 - 07:12 PM

oop, by full frame I meant academy.


You were more correct the first time, anamorphic makes full use of the 35mm frame area with a x 2 squeeze.
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#9 Chris Millar

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Posted 19 January 2012 - 07:23 PM

I understand anamorphic ... I was referring to old school academy 4:3 - I thought 'full frame' might refer to or be misunderstood with super35 which has different acqusition vs. projection placement in the frame.

Maybe there is super35 anamorphic DI workflows - not sure ?
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#10 David Mullen ASC

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Posted 19 January 2012 - 10:57 PM

The 4-perf 35mm Full Aperture is the largest area you can expose in 4-perf and was used by Silent Era movies -- that format is 1.33 : 1 (4x3). 4-perf Super-35 is more or less the same thing, but is almost always composed to be cropped to some widescreen format.

Then in 1928-ish the left side of the Silent Era print area was cropped with a projector aperture plate to make room for an optical soundtrack, creating a 1.20 : 1 shape that was called the Movietone Aperture.

That was deemed too square-ish so the top and bottom of the print area was also cropped a little to reduce the height in 1932, so including the loss of the left side for the optical soundtrack, the area became 1.37 : 1 and was called the Academy Aperture.

"Full Frame" is more of a still photography term and usually refers to the 8-perf horizontal 35mm format that is 36mm x 24mm. That shape is around 1.5 : 1.

The thing to remember is that projector masks create a certain amount of cropping, so the shape of the negative isn't necessarily the shape of the projected frame, hence why you have frameline markers in the viewfinder in order to compose for the intended release format.

The anamorphic 35mm format is 4-perf and uses almost the same area as the Movietone format, which is nearly Full Aperture height by Academy Aperture width, close to a 1.20 : 1 area. With the 2X horizontal squeeze from the anamorphic lenses, the image -- once unsqueezed laterally by 2X using an anamorphic projector lens / combined with the nearly 1.20 : 1 gate in the projector -- becomes nearly 2.40 : 1.
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#11 Chris Millar

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Posted 19 January 2012 - 11:03 PM

The thing to remember is that projector masks create a certain amount of cropping

Enough cropping to necessitate liquid cooled aperture plates in some projectors :blink:
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#12 Brian Drysdale

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Posted 20 January 2012 - 03:48 AM

I understand anamorphic ...


David explains the aperture better by giving the gate height detail. It makes full use of the available negative area.
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