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What are the disadvantages of cropping to 2.40?


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#1 Adam Paul

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Posted 16 July 2006 - 04:23 PM

Are there any disadvantages in cropping Varicam 16:9 footage to 2.40 if it will be projected digitally?
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#2 Max Jacoby

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Posted 16 July 2006 - 05:25 PM

You're using a smaller part of the chip so the resolution will drop a bit.
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#3 Adam Paul

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Posted 16 July 2006 - 06:07 PM

I have heard that but quite frankly it confuses me since I don?t really see how. If you were blowing the footage up, I could see it getting softer, but the width stays the same. Only the height gets shortened. So if you would project the16:9 footage on a 30feet wide screen, the 2.40 version would have the very same 30feet width, just wouldn?t be as tall. So how is ti losing resolution or looking softer? I could see it if the footage would be transferred to 35mm and blown by an anamorphic projector lens, but projecting digitally?
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#4 Fredrik Backar FSF

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Posted 16 July 2006 - 06:44 PM

pixels per area will still be the same yes. What I think Audiris is saying is, that the less u use of a chip which to start with has bad resolution for a cinema screen, the less good every object on the chip will turn out as it will be composed smaller naturally to accomodate the framing in 2.40... And; a projected image of 2.4:1 should always have same height if good cinema. Otherwise the cinema would just be showing the widescreen within the initial 4:3 screen with black top´n´bottom and that´s no fun for us bigscreen lovers.
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#5 David Mullen ASC

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Posted 16 July 2006 - 07:21 PM

Depends on the theater -- most theaters use a wider screen for 2.40 and bring in black curtains to shorten the width for 1.85. So if you had a letterboxed 2.40 HD image being digitally projected and you had to zoom out the image to fill the wider 2.40 screen and lose the letterboxing, you'd be enlarging the image more plus the projector light output drops 30%.

Now if you can make a conversion tape so that 2.40 was stretched to fill 16x9 on a special HD version, and had the right anamorphic projector lens on the digital projector to unstretch it, then you'd be using all the pixels for the projector and not losing light output, although you are still working with fewer overall pixels of the original.

Because digital images have some flexibility in being resized and reshaped, the loss from cropping 16x9 HD to 2.40 isn't that noticeable, but there is loss. Once the image is enlarged to fill a wider screen, you tend to notice the video artifacts a little more, like noise, edge enhancement, aliasing problems -- but it is a subtle difference.

Also, the Varicam captures a 1280 x 720 pixel image, so you'd be using only 1280 x 535 pixels for a 2.40 image.
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#6 Adam Paul

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Posted 16 July 2006 - 07:50 PM

So it would basically lose 30% resolution, if not how much? How about a 1.85 crop then? Just would like something wider than the normal HDTV 16:9, but don't want to lose sharpness because 1280x720 is already not that sharp.
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#7 David Mullen ASC

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Posted 16 July 2006 - 07:58 PM

1.85 and 16x9 (1.78) are really close to the same shape, just a few scan lines of black to letterbox 16x9 to 1.85. 2.40 is the only significantly wider shape for theatrical projection, unless you want to do what Storaro does for his 2.00 : 1 Univisium movies, which involves black masks on the print (usually scope release prints with side mattes to shorten 2.40 to 2.0). In your case, you could put a 2:1 letterbox on an HD tape and show it that way. You just may have black visible on the screen if you can adjust the screen masking to hide it.
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#8 Adam Paul

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Posted 16 July 2006 - 08:14 PM

So it seems it's not really worth to crop to 1.85.
How much per cent do you lose with the 2.40?
The 2.0 sounds a little odd. Also, it doesn't seem like it would be that much wider than 1.85
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#9 Dan Goulder

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Posted 16 July 2006 - 08:53 PM

So it seems it's not really worth to crop to 1.85.
How much per cent do you lose with the 2.40?
The 2.0 sounds a little odd. Also, it doesn't seem like it would be that much wider than 1.85

Forget about all these numbers you're throwing around. What aspect ratio do you want for your project? How would you like the shots to be framed? What lends itself best to the project? Let THAT be your guide.
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#10 Adam Paul

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Posted 17 July 2006 - 04:47 AM

Well, if I consider all that, the answer screams 2.40. But if it will look too soft, I have to compromise and leave it at 1.66 or cut it to 1.85 or the odd 2.0 David mentioned. Though call really. I just wish we could shoot 1080p, so I think it would be no problem cropping to 2.40 since Star Wars looked ok that way. But 720p is already not that sharp for starters. But hey, the Varicam is free at least.
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#11 Fredrik Backar FSF

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Posted 17 July 2006 - 07:26 AM

Now hey! Here´s an idea. Did tests with HD and a Pro-35 adaptor with anamorphic on. looked nice.but u still lose the resolution in essence.
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#12 Adam Paul

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Posted 18 July 2006 - 05:57 AM

Something else came to mind after reading this reply from David Mullen on a different thread:

"The short imprecise answer is that the smaller the target area, the shorter the focal lengths get on average, and shorter focal lengths generally create more depth of field than longer ones. You'll note that the typical zoom range for Super-16 and 2/3" CCD cameas is something like 10mm-100mm, etc. whereas for 35mm it would be 25mm-to-250mm, etc. With Super-8 and 1/3" CCD cameras, it's more like 4mm-to-40mm, etc.
With 35mm anamorphic and 5-perf 65mm, the range would be more like 50mm-to-500mm rather than 25mm-to-250mm to achieve the same fields of view."

So I was thinking if we decide to go with 2.40, will our lenses be a problem when composing to 2.40? We will use digiprimes (7,10,14,20,28,40). Do I need the longer ones?

Fredrik Backar , about the option of using anamorphic lenses on a Pro35, I think the Pro35 might soften the image a bit much. Remember it?s 720p we are shooting, not 1080p. Also, 35mm anamorphic lenses have a 2x squeeze, which would make the 16:9 image way too wide I guess. On the top of that, we have the digiprimes available for free with the Varicam package. Anamorphic lenses are also big and slower. Given the Pro35 loses a lot of light, slower lenses are not really that great of an option for it.

Edited by Adampaul, 18 July 2006 - 05:58 AM.

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#13 Max Jacoby

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Posted 18 July 2006 - 07:23 AM

Something else came to mind after reading this reply from David Mullen on a different thread:

With 35mm anamorphic and 5-perf 65mm, the range would be more like 50mm-to-500mm rather than 25mm-to-250mm to achieve the same fields of view.[/b]"

So I was thinking if we decide to go with 2.40, will our lenses be a problem when composing to 2.40? We will use digiprimes (7,10,14,20,28,40). Do I need the longer ones?

Don't worry, this will not be an isse for you.

Remember the focal lenght of the lens by itself does not tell you how 'wide' or 'long' a lens is, but it is conjunction with the format that you will be shooting.
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#14 John Pytlak RIP

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Posted 18 July 2006 - 10:01 AM

A "rule of thumb" in still photography was that a "normal" lens had a focal length that matched the diagonal of the film format:

http://en.wikipedia....iki/Camera_lens

Normal lens: angle of view of the diagonal about 50°: a focal length approximately equal to the diagonal produces this angle.


http://www.shortcour...g/lenses/10.htm

So what makes a lens focal length wide, normal, or long? When the focal length of a lens is close to the diagonal measurement of the film format, the lens is said to be "normal" or close to the magnification of the human eye. When the focal length of a lens is longer than the film diagonal, it's a "long" or telephoto lens. When the focal length is shorter than the film diagonal, it's a "short" or wide-angle lens. Since the placement of lenses into these categories is based on the film size being used, a given focal length might be considered normal on one type of camera, wide angle on another, and telephoto on a third.


http://www.panoramaf...35/equiv35.html

What makes a lens "normal?"

A "normal" lens produces a field of view that is similar to human vision. The diagonal of the image plane is typically used as the reference for field of view determination. A "normal" lens has a focal length that is approximately equal to the diagonal measurement of the image plane. When the focal length is equal to the diagonal measurement it produces a diagonal field of view of approximately 53° which is similar to human vision.

For 35mm film (24mm by 36mm), the diagonal measurement is 43.27mm. 50mm is close to this measurement so it is considered a "normal" lens. A 50mm lens produces a 47° diagonal field of view which is close to 53°.


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#15 Fredrik Backar FSF

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Posted 19 July 2006 - 02:50 AM

You would of course be shooting in 4:3 with you HD cam hence the still apparent lack of resolution I was reffering to. Did filmout tests for a feature together with with another DP (Eric Maddison) that compared
The new Canon digiprimes, Zeiss HS on Pro-35 and regular 500asa s-16mm with Zeiss HS.
Of course I liked the film the most with graintextures and great tonalrange/skintones, but when comparing filmoutmaterial with and without pro-35 from the HD-cam. Pro-35mm footage was superior as it rendered a heightened feeling of film; much better highlights, nicer tones going into black and a more textured feel thanx to the moving ground-glass in the adapter. The digiprime Filmout just felt cold 2-dimensional and lacking all terms naighing textured. Sharp?: Yes! But good?: NO!
Film is not all about sharp is it. Video is right now fighting to heighten resolution, hence the feel of reality. And who wants to see films that look like what u see every day? Film should (I think, if nothing else intended) thwart you from reality and paint a place of "somewhere else".
Sorry for going into this film/video debate again..... I´ll stop it right now :D
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