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Different lenses depending on aspect ratio?


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#1 Matt Harris

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Posted 20 March 2012 - 03:54 AM

I'm curious if there is a rule when shooting 2.35:1 vs 16:9 when it comes to choosing lenses. For example, if I want to fill the frame with someones face using a 135mm lens, I will obviously be standing in a different place depending on which aspect ratio I'm using. Do most cinematographers compensate by using a shorter focal length for cinescope? Sorry for the silly question.
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#2 Freya Black

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Posted 20 March 2012 - 06:59 AM

Not sure where to start with that. Cinemascope lenses often come in a much more limited variety of focal lengths, and may be much more limited at the wider end of the focal length spectrum for example. I'm not sure why you think you would need to stand further back tho as the focal length remains the same for anamorphic or flat lenses, It's just the anamorphic lenses give a wider aspect ratio.

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#3 John Holland

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Posted 20 March 2012 - 07:40 AM

If you shoot a scene with 50mm spherical lens and wanted to shoot the same scene with a anamorphic lens from the same position you would use a 100mm , they are almost twice the focal length .
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#4 Freya Black

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Posted 20 March 2012 - 08:51 AM

If you shoot a scene with 50mm spherical lens and wanted to shoot the same scene with a anamorphic lens from the same position you would use a 100mm , they are almost twice the focal length .


Really? Or do you mean lenses with anamorphic adaptors?

I've shot quite a bit with an anamorphic adaptor on a zoom lens but it never seemed THAT much wider but it might have been because I was avoiding vignetting. Really suprised. So a 35mm anamorphic prime would be the equivalent of 15mm in flat lenses? Thats actually really good news!
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#5 Travis Gray

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Posted 20 March 2012 - 09:06 AM

I'm curious if there is a rule when shooting 2.35:1 vs 16:9 when it comes to choosing lenses. For example, if I want to fill the frame with someones face using a 135mm lens, I will obviously be standing in a different place depending on which aspect ratio I'm using. Do most cinematographers compensate by using a shorter focal length for cinescope? Sorry for the silly question.


Are you actually shooting anamorphic or just doing a 2.35 crop? If just a crop, obviously your field of view is going to change a bit, height-wise, but it won't affect focal length. If I'm shooting something and I want to do a 2.35 crop, I might go wider though just to be able to fit in more of the background and then move closer to get a tighter shot on the subject. I think it would depend on what you're shooting too.
If I want to hide locations, I'm going to probably shoot 16x9 and keep tighter to the subjects.

A good tool to check, if you're on an iPhone, is CeneCalc. It has a field of view calculator that allows you to see different crops on different sensors and pick your focal length and distance and see how subjects fill the frame.


If you are doing anamorphic though, I have no idea haha. I have yet to shoot true anamorphic.
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#6 Brian Drysdale

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Posted 20 March 2012 - 09:40 AM

Really? Or do you mean lenses with anamorphic adaptors?

I've shot quite a bit with an anamorphic adaptor on a zoom lens but it never seemed THAT much wider but it might have been because I was avoiding vignetting. Really suprised. So a 35mm anamorphic prime would be the equivalent of 15mm in flat lenses? Thats actually really good news!


Film anamorphic lenses have a X 2 squeeze, if you were using an adapter on a 16:9 video camera you'd need less squeeze, more like around 1.33.

Of course, shooting on a Super 35 sensor that has a 16:9 aspect ratio, the sums change.
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#7 Freya Black

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Posted 20 March 2012 - 10:10 AM

Film anamorphic lenses have a X 2 squeeze, if you were using an adapter on a 16:9 video camera you'd need less squeeze, more like around 1.33.

Of course, shooting on a Super 35 sensor that has a 16:9 aspect ratio, the sums change.


Good point Brian, I was on a 1.5x adaptor. Hadn't thought of that, I must be half awake or something today!
Wasn't even scope exactly.

All the same I didn't realise the stretch was also affecting the effective focal length to such a degree.
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#8 John Holland

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Posted 20 March 2012 - 01:02 PM

A 35mm anamorphic is about the same of a maybe 20mm spherical . Remember because of their longer focal length the depth of field is half of a "flat" lens so you do have stop down more .
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#9 David Mullen ASC

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Posted 21 March 2012 - 07:46 AM

The focal length doesn't change, but 2X anamorphic lenses squeeze twice as much horizontal view compared to a spherical lens so "act" more wide-angle, at least in horizontal view. Since the Anamorphic 4-perf 35mm camera aperture is a sound format, Academy Aperture in width, and Super-35 uses the Silent / Full Aperture width, the difference in view between 35mm anamorphic 2.40 versus Super-35 cropped to 2.40 isn't quite half or double, but close.
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