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Author Topic: hyperfocal focusing  (Read 10495 times)

ErikKaffehr

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Re: hyperfocal focusing, strictly talking
« Reply #20 on: January 07, 2016, 02:45:48 pm »

Hi,

Strictly speaking, hyperfocal focusing is a technique that guaranties that everything will be out of focus except a single plane of focus which happens to be half way between infinity and closest distance.

Best regards
Erik
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Erik Kaffehr
 

AFairley

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Re: hyperfocal focusing, strictly talking
« Reply #21 on: January 08, 2016, 11:58:59 am »

Hi,

Strictly speaking, hyperfocal focusing is a technique that guaranties that everything will be out of focus except a single plane of focus which happens to be half way between infinity and closest distance.

Best regards
Erik

+1  :)
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dwswager

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Re: hyperfocal focusing
« Reply #22 on: February 20, 2016, 10:19:02 pm »

The problem with depth of field and hyperfocal calculations is that the calculations (and depth of field markers on the lens) often assume a small print size (~8x10 inches) and a viewer with less than 20/20 vision. For a viewer with 20/20 vision and a print size of 16x24 inches, the depth of field is considerably less.

Here are the results for your parameters as calculated by the Cambridge in Color calculator:

Regards,

Bill

What's missing from the Cambridge calculator is what "circle of confusion" their calculator selects to use for the hyper focal calculations with a 24" print size, 25cm viewing distance and 20/20 vision.   

I consider the used parameters not only meaningless, but foolish.  I have 24" (long edge) prints on my wall and usually they are viewed by some 10 feet, not 10 inches!  If we just change the viewing distance to 1m (3ft), then the hyperfocal distance becomes 13.18ft and we get 6.8' to infinitity in focus even with 20/20 vision.

Hyperfocal calculations are based on the CoC which should be selected based on print size and REASONABLE viewing distances.  We cannot control for eyesight so "normal" vision is assumed.  A 4"x 6" print would normally beviewed from 10" or more. I am reminded of early ink jet printesr and people screaming "I can see the dots".  Well yeah, when viewing a print with a 4x loupe!
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FranciscoDisilvestro

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Re: hyperfocal focusing, strictly talking
« Reply #23 on: February 21, 2016, 03:48:53 am »

Hi,

Strictly speaking, hyperfocal focusing is a technique that guaranties that everything will be out of focus except a single plane of focus which happens to be half way between infinity and closest distance.

Best regards
Erik

Well, I guess you refer to the non-linear distance scale of the lens (hyperbolic) because strictly speaking, something half way between infinity and anything is at infinity too, but I'm sure you know that.  :)

I find it easier to understand is that the single plane of focus which is sharp (hyperfocal distance), is at twice the closest distance.

E.g, for a 50 mm lens for 35 mm full frame, using the "classical" criteria, the hyperfocal distance at f/16 is 4.94 m. and the closest distance is 2.47 m.  -> 4.94 = 2.47*2

dwswager

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Re: hyperfocal focusing, strictly talking
« Reply #24 on: February 22, 2016, 08:53:41 am »

Hi,

Strictly speaking, hyperfocal focusing is a technique that guaranties that everything will be out of focus except a single plane of focus which happens to be half way between infinity and closest distance.

Best regards
Erik

Not sure the point of this statement because it is true, strictly speaking, no matter what focusing technique is used or where the lens if focused.  There will be a single plane in absolute focus and everything else will be out of focus.

The point of hyperfocal focusing is to permit imagery where there are close foreground objects and far background objects that are intended to be in focus.  Of course, applying this technique when the closest object in the image is beyond the hyperfocal distance means the photographer is foolish, but the technique is still sound.. 
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Ludwig Nobel

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Re: hyperfocal focusing, strictly talking
« Reply #25 on: February 26, 2016, 01:03:37 am »

There will be a single plane in absolute focus and everything else will be out of focus.

Chuck Norris has everything in focus. From zero to infinity. And beyond. At f 1.4. Handheld in low/no light. Even without a lens.
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