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what do you call it when a lens....


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#1 ross e lea

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Posted 09 July 2009 - 08:00 PM

what do you call it when a lens actually
bends or warps the sides of the image.

is it qualities only from an anamorphic lens?

please explain. thank you very much ya'll

ross
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#2 ross e lea

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Posted 09 July 2009 - 08:07 PM

particularly when change of focus occurs!
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#3 David Mullen ASC

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Posted 09 July 2009 - 08:55 PM

Bending on the sides can either be barrel distortion or pincushion distortion. Barrel distortion causes vertical lines near the sides to bulge outwards and pincushion does the opposite.

There is also things like portholing and fall-off, sort of a soft vignette.

Focus racks that cause a visible shift in focal length, a slight zooming, is called "breathing".

Anamorphic lenses also breathe but for a different reason, focus racks cause the amount of squeezing in the background to change, making things in the background stretch or compress (back to normal) vertically. And the wider-angle anamorphic lenses often have a lot of barrel distortion to boot, so you see both the breathing during focus racks and the barrel distortion.
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#4 K Borowski

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Posted 09 July 2009 - 11:16 PM

Anamorphic lenses also breathe but for a different reason, focus racks cause the amount of squeezing in the background to change, making things in the background stretch or compress (back to normal) vertically. And the wider-angle anamorphic lenses often have a lot of barrel distortion to boot, so you see both the breathing during focus racks and the barrel distortion.


While, technically, this is a flaw of the process, I have always found the effects rather pleasing when watching anamorphic movies. The focus seems to "jump" off the screen, rather than remaining subtle.
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#5 ross e lea

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Posted 10 July 2009 - 12:00 AM

[quote name='David Mullen ASC
Focus racks that cause a visible shift in focal length, a slight zooming, is called "breathing".
Anamorphic lenses also breathe but for a different reason, focus racks cause the amount of squeezing in the background to change, making things in the background stretch or compress (back to normal) vertically. And the wider-angle anamorphic lenses often have a lot of barrel distortion to boot, so you see both the breathing during focus racks and the barrel distortion.
[/quote]

yes. I love the effect it produces because it really allows focuses to POP! and I'm trying to mimic that in Maya (animation)

Is there intentional zooming going on at the moment of changing focus in order to accomplish that? or is more about how the lens responds to light with DOF?


and thanx for your time. you're great David.

ross
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#6 Chris Keth

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Posted 10 July 2009 - 12:32 AM

yes. I love the effect it produces because it really allows focuses to POP! and I'm trying to mimic that in Maya (animation)

Is there intentional zooming going on at the moment of changing focus in order to accomplish that? or is more about how the lens responds to light with DOF?


and thanx for your time. you're great David.

ross


It's just a by-product of lens mechanics. It's funny you like it and are trying to replicate it because most people consider it a bad thing, and a distraction to what would otherwise be a nice subtle focus rack.
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#7 ross e lea

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Posted 10 July 2009 - 01:35 AM

It's just a by-product of lens mechanics. It's funny you like it and are trying to replicate it because most people consider it a bad thing, and a distraction to what would otherwise be a nice subtle focus rack.



yeah...sorry...it's just one of those things where I find the "flaw" to be an authentic, special character and not a hinderance to making the art of film. I think HD and the advancement of everything being easy & perfect
will eventually fade and people will start to be drawn back to the little things that made movies great! ya know!?
ok, now I'm just rambling...LOL.
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#8 Chris Keth

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Posted 10 July 2009 - 12:26 PM

yeah...sorry...it's just one of those things where I find the "flaw" to be an authentic, special character and not a hinderance to making the art of film. I think HD and the advancement of everything being easy & perfect
will eventually fade and people will start to be drawn back to the little things that made movies great! ya know!?
ok, now I'm just rambling...LOL.


Don't apologize. If you want to do it, do it. I was just telling you more about it. You have the benefit of being able to control when it happens, which direction the little zoom happens, and how much focal length change there is. If you want the rack to be accompanied with a little push in, that could be really cool sometimes.

The problem is that we can't control when and how it happens so if you try to so something subtle, it pretty much ruins the subtlety. That is why it's usually considered bad, because of the lack of control of that element. If we want a rack with a little zoom, we'll put a zoom on and do it in a way that we can control.
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