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HD Depth of Field Charts


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#1 Stephen Whitehead

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Posted 17 June 2005 - 08:00 PM

Hey, does anyone know where about a depth of field chart for HD, namely the CineAlta can be found?

Cheers,

Steve
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#2 Mike Brennan

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Posted 18 June 2005 - 03:16 PM

Hi Steven,
I suggest that you make your own notes.
In doing so you'll learn how the focus falls off slowly especially on wider lenses and the effect of in-camera detail on out of focus backgrounds.

1920x1080 LCD display should do the trick for you.



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#3 Stephen Whitehead

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Posted 18 June 2005 - 05:14 PM

Now I am familier of course with wider angle lenses' effects on DOF. My thing is that I have worked mostly with 35mm, and 16mm and now am being asked to shoot HD. What exactly do you mean by the cameras effect on background detail? is there some sort of filter that the camera applies?

Cheers,

Steve
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#4 Dudu Stoz

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Posted 20 June 2005 - 10:06 AM

the DOF calculation on HD are the same as with film exept circle of confusion is 15 micron.
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#5 Dudu Stoz

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Posted 20 June 2005 - 10:15 AM

In doing so you'll learn how the focus falls off slowly especially on wider lenses and the effect of in-camera detail on out of focus backgrounds.

Mike Brennan

<{POST_SNAPBACK}>


sorry,
but the in camera detail has nothing to do with soft focus in the background(or in the forgound) it is the electronic detail enhancing of sharp objects - to be precice the detail enhancing circle drowin black an white lines arround lines where video level or croma vector changes radicaly.
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#6 Stephen Williams

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Posted 20 June 2005 - 10:34 AM

sorry,
but the in camera detail has nothing to do with soft focus in the background(or in the forgound) it is the electronic detail enhancing of sharp objects - to be precice the detail enhancing circle drowin black an white lines arround lines where video level or croma vector changes radicaly.

<{POST_SNAPBACK}>



Hi,

However too much detail will make everything look sharper. If you have good lenses you should be able to turn off the detail!

Stephen
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#7 Dudu Stoz

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Posted 20 June 2005 - 05:40 PM

If you have good lenses you should be able to turn off the detail!

Stephen

<{POST_SNAPBACK}>


well for my opinion the detail enhancment is good for anything to be broadcast in television, with detail off it will look too soft even with a sharp lens - but for anything going to teathral release the detail correction is too visible so it is better to turn it off as you said
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#8 Stephen Williams

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Posted 21 June 2005 - 02:02 AM

well for my opinion the detail enhancment is good for anything to be broadcast in television, with detail off it will look too soft even with a sharp lens - but for anything going to teathral release the detail correction is too visible so it is better to turn it off as you said

<{POST_SNAPBACK}>



Hi,

We are talking about a Cine Alta camera! The Panavision default is off as no extra detail is required as the lenses are so sharp. But for a video camera with a cheap zoom lens, well thats another story.

Stephen
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#9 Mike Brennan

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Posted 21 June 2005 - 04:18 PM

sorry,
but the in camera detail has nothing to do with soft focus in the background(or in the forgound)

<{POST_SNAPBACK}>



Nothing to do with soft background?
Try it and see if it has no effect on the background.



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#10 Mike Brennan

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Posted 21 June 2005 - 04:28 PM

the DOF calculation on HD are the same as with film exept circle of confusion is 15 micron.

<{POST_SNAPBACK}>


It is dangerous quoting depth of field numbers made for film.
Although the theory of optics is the same, HD capture and display is different than film, for which the depth of field charts were designed (someone correct me if I'm wrong here)

The "apparent" depth of field decreases with the resolution of the display.
So it could be less on HD, when viewed on a HD display or digital projector than on 16mm projected on film.


Ask yourself,
Who created the depth of field tables?
captured on what medium?
and viewed on what display?



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#11 David Mullen ASC

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Posted 21 June 2005 - 04:38 PM

The "apparent" depth of field decreases with the resolution of the display.
So it could be less on HD, when viewed on a HD display or digital projector than on 16mm projected on film.
Ask yourself,
Who created the depth of field tables?
captured on what medium?
and viewed on what display?
Mike Brennan

<{POST_SNAPBACK}>


Now you understand why I believe depth of field charts will always only be an approximation anyway. Too many variables, too many end product destinations.

Anything that is critical should be tested for the worst-case final viewing format, otherwise just understand that it's only a ballpark calculation.
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#12 Dudu Stoz

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Posted 22 June 2005 - 06:35 AM

Anything that is critical should be tested for the worst-case final viewing format, otherwise just understand that it's only a ballpark calculation.

<{POST_SNAPBACK}>


15 micron CoC calculation is the number that will suit for the worst-case viewing format.
because unlike in film focus is not a defenitive thing it ranges within the size of the pixel
which is ~ 14 micron in HDCAM - so if a dot of light sourse focuses inside 1 pixel it is no mather how big the screening projection will be, the dot will only fill this one pixel,
which i think makes this DoF calculation a definitive thing.
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Paralinx LLC

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Rig Wheels Passport

Media Blackout - Custom Cables and AKS

rebotnix Technologies

Ritter Battery

Willys Widgets

The Slider

Visual Products

CineTape

Metropolis Post

Aerial Filmworks

Broadcast Solutions Inc

Glidecam

Abel Cine

Technodolly

CineLab

Tai Audio

Wooden Camera

Gamma Ray Digital Inc