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Bokeh on Anamorphics


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#1 Matthew Twyford

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Posted 08 January 2008 - 01:11 PM

Hi All,

my first post so be gentle on me :lol:

I am making a digital filter to roughly match the extended oval bokeh produced by the 'anamorphic breathing' of some anamorphic lenses. An example in a previous thread.

http://www.cinematog...showtopic=27763

These filters will be applied to digitally generated background plates that need to match live action plates from the same scene. Initially this will be for C and E series primes but I hope to be able to cover a larger range of lenses in the future.

Some questions for you all with experience shooting or testing with these lenses.

1. Is it possible for the blur shape to elongate even more than say a 2:1 ratio the further away you get from the plane of focus.
2. Does anyone know if the shapes get stretched vertically and/or squeezed horizontally?
2. I cannot find any examples of what would happen to a point light source in front of the plane of focus. Can any one let me know what shape/ orientation the blur shape will become?
2. If you shoot wide open would you start to get a cat's eye bokeh, has any one tried?
4. How does the position of the anamorphic element in the lens change this effect ie. do you still get elongated blur shapes with the Hawk lenses or adapted lenses?
5. Does it all get a bit chaotic with the zooms or do similar results apply?

Thanks for your help and thoughts,

Matt
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#2 Paul Bruening

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Posted 08 January 2008 - 02:49 PM

Recently, there was a thread here addressing one of the peculiar characteristics of anamorphic bokeh (listed in your post). It seems that the subject area can desqueeze normally, yet background bokeh brightspots continue in squeeze (oval). We've wrestled with the mental concept of anamorphic lenses working in two focal lengths at the same time, just on differing axis. It's a little challenging to wrap the brain around since the phenomena occurs in varying degrees from the center-outward. It's not even as obvious as x-axis times y-axis since one axis is spherically based and the other is spherical times column lens.

The reason I mention this is that you're designing a digital replication of the anamorphic phenomena. For DPs, it's mostly just a matter of using the lenses and accommodating their peculiarities. You, on the other hand, have to get and apply all of the concepts underlying their behavior in order to replicate their results.

Good luck. Eat lotsa' fish.
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#3 David Mullen ASC

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Posted 08 January 2008 - 04:01 PM

The squeezing error that creeps in is mainly a phenomenon of front (or middle to some extent) anamorphic designs, not rear-anamorphic lenses.

It gets worse as the object goes more out of focus and then stabilizes, but since an object that is nearly in focus hasn't yet become an abstract circle or oval, I'm not sure you'd call that a bokeh characteristic -- that term sort of loosely describes completely out of focus objects that create a distinctively textured 2D background.

Was just watching the newish Criterion DVD of "The Leopard" by Visconti, shot in Technirama with 1.5X anamorphic optics -- saw the same ovals but not quite as skinny as 2X anamorphics seem to create. The DVD looks great, by the way.
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#4 Leo Anthony Vale

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Posted 08 January 2008 - 04:23 PM

Was just watching the newish Criterion DVD of "The Leopard" by Visconti, shot in Technirama with 1.5X anamorphic optics -- saw the same ovals but not quite as skinny as 2X anamorphics seem to create. The DVD looks great, by the way.


I was recently watching bits of 'The Fall of the Roman Empire' and 'The Greatest Story Ever Told', both are Ultra Panavision, 1.25x squeeze.
& they also have the same bokeh, again not as skinny, but there. Also slightly curved horizontals.

The lengthy documentary for 'The Greatest Story...' has Bob Gottschalk saying that it was going to be filmed in Super Panavision and the camera package was ready to ship, when he showed Stevens some Ultra Panavision test footage and Stevens decides on the spot to change to Ultra Panavision.
Gottschalk protests that he doesn't have enough lenses yet for the movie, he only give him two or three for now, it'll take awhile to make enough for the picture.
Stevens tells him that he's sure that they can get them built in time.
So Panavision has to work lots of overtime to finish the lenses.
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#5 David Mullen ASC

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Posted 08 January 2008 - 09:41 PM

I read an article that said that they shot the first three days of "The Greatest Story of Ever Told" on three-camera Cinerama and then junked the footage and went with Ultra Panavision.
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#6 Leo Anthony Vale

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Posted 09 January 2008 - 02:45 PM

I read an article that said that they shot the first three days of "The Greatest Story of Ever Told" on three-camera Cinerama and then junked the footage and went with Ultra Panavision.

I've read that too. But I'm in no position to call Gottschalk a liar.

I've tried to correlate shooting dates of 'Greatest Story...' with those of 'Mutiny on the Bounty' and 'It's a Mad, Mad, Mad, Mad World', thinking that if Panavision didn't have enough Ultra Panavision lens it was because thay were out on one of those pictures. But the library has once again designated TCM.com as a sex site and is denying access. IMDb.com only gives release dates, TCM often gives actual shooting dates.
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