My camera records something called "Hyperfocal Distance". I'm not sure what it is, but from that (and maybe with other parameters), can I calculate the actual focus distance? Or is that it, just with a different name?
Cheers
Alan
April 9, 2024
9
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photographylife.com/hyperfocal-distance-explained
From my understanding you couldn't because the hyperfocal distance is a function of focal length and aperture. You may have focused anywhere in or out of that range. But if you knew your focal distance, you can work out your acceptable depth of field, as fractions of H.
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Thanks.
Alan
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Alan, This is fairly readable yet pretty accurate. There are three concepts, the hyperlocal distance near (between the focal point and camera), the hyperlocal distance far (between the focal point and infinity) and the DOF which is their difference that go into calculating the hyperlocal distance.
www.waloszek.de/gen_dof_e.php#:~:text=exact%22%20aperture%20values.-,Calculating%20the%20Hyperfocal%20Distance,%2F(N*c)%20%2B%20f
What causes most of the confusion with digital cameras, other than "equivalence" is the circle of confusion. The circle of confusion, CoC or c in most equations is the size of a disk that the human cannot distinguish from a point. That is a property of human vision and it is different when viewing a print vs. 100% on a digital display. It varies with the distance at which the image is viewed. It is pretty simple of pixel peekers and is normally taken as 1.5 times the diameter of a pixel or the size a patch 3 pixels on a side viewed close to the display. However, viewing a 27 inch display at a more normally at two to three feet the CoC is larger. Viewed on a print in a gallery, it is larger still.
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That's interesting. It means that my Fuji X-T5's with a 40mp APS-C sensor has a smaller DoF than an X-T4's 26mp sensor because each photosite is smaller and therefore the CoC is smaller.
So, just saying it's APS-C sensor doesn't really help.
Alan
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( from Wikipedia )
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But the accepted (?) criteria for CoC is 3 pixels (a 9 pixel square). Which means the size varies depending in the pixel density.
Alan
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Yes if pixel peaked at 100% with your nose to the screen. No if viewed at a "normal viewing distance" of 1.5 times the diagonal of the image.
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If that is the accepted value of CoC, how come the commonly used DoF calculators (e.g. dofmaster.com) don't use the pixel density in their calculations?
I think most use the value 0.030mm for full-frame and scaled in proportion to the sensor diameter for other formats (e.g. 0.015mm for MFT). I like to think of that as CoC = image diameter/1500 (approx.).
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But isn't the essence of the excercise CoC is part of identical viewing conditions of the output?