# Circle of confusion for S16 to 35 blow-ups

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### #1 Uwe Pfizenmaier

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Posted 16 February 2006 - 09:38 PM

Hey all! In the book Practical Cinematography by Paul Wheeler, it is written that depth of field calculations should be based on a 1/2000? circle of confusion when shooting Super 16 for blow-up to 35mm as opposed to e.g. 35mm for theatrical release at 1/700?-1/1000?. (p.99 ff)
Is that assumption of the circle of confusion true?
Mr Wheeler states that 35mm is about 2.5 times sharper than 16mm film projected to the same screen size. Taking the regular circle of confusion of 35mm at 1/700? and dividing it by 2.5 we end up a around 1/2000?, which is necessary to make 16mm projected on 35mm ?as sharp as? it would have been shot on 35mm originally.
Is that theory correct? Can somebody help me to get that straight? Thanks a lot!
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### #2 Laurent Andrieux

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Posted 17 February 2006 - 07:27 AM

Sounds good to me
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### #3 Stephen Williams

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Posted 17 February 2006 - 08:59 AM

Hey all! In the book Practical Cinematography by Paul Wheeler, it is written that depth of field calculations should be based on a 1/2000? circle of confusion when shooting Super 16 for blow-up to 35mm as opposed to e.g. 35mm for theatrical release at 1/700?-1/1000?. (p.99 ff)
Is that assumption of the circle of confusion true?
Mr Wheeler states that 35mm is about 2.5 times sharper than 16mm film projected to the same screen size. Taking the regular circle of confusion of 35mm at 1/700? and dividing it by 2.5 we end up a around 1/2000?, which is necessary to make 16mm projected on 35mm ?as sharp as? it would have been shot on 35mm originally.
Is that theory correct? Can somebody help me to get that straight? Thanks a lot!

Hi,

That's spot on.

DOF is actually the same regardless of format when you project to the same size, assuming there is enough resolution in the smallest format. You must use very sharp lenses for super 16.

Stephen
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