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09-01-2016, 05:56 PM   #1
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using hyperfocal distance HFD

I have a variety of prime lenses and an app to calculate the hyperfocal distance. I have had sucess with the 31mm f/1.8 as the HFD is quite easy to focus on since the distance is easliy measured . I use the live screen, peak focus with a hoodman loupe and can achieve a remarkable depth of field. I have a Zeiss 85 f/1.4 and the app returns a much greater HFD. In order to focus at this distance, accurately sometimes 60, 70 plus meters. From what I have read, this distance must be quite accurate and the distance scales are hardly a reflection of the required accuracy. Focusing 1/3 into the distance is very subjective to me. Can HFD be used for longer focal length lenses or is it really just for shorter focal lengths and if it can used with longer focal lengths, an HFD is known by app or calculation, how do you know, to the required accuracy, where that is when you are focusing on it? Thank you in advance for any help or advice.

09-01-2016, 08:45 PM   #2
dms
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I am confused--you ask about Hyperfocal distance (H), but then speak of focusing 1/3 of the distance? Actually hyperfocal distance is the distance for which acceptable focus will be from 1/2 H to infinity. There is no 1/3 of the way to infinity. That 1/3 rule applies to depth of field and moderate distances! Also when using long focal length and/or fast lens close to wide open it is unlikely you would be using hyperfocal distance, thus your talking about numbers like 70 meters distance are odd (to me).

Nevertheless, about hyperfocal distance--if your lens has depth of field markings--just focus on the closest area of interest, and then choose an f stop for which the depth of field covers this closest distance and infinity. Actually if using a 1.5x cropped sensor and a FF lens, then when done reset the lens to one f-stop more closed down.

If the lens doesn't have depth of field markings you shouldn't need to know precisely the distance. As an example if the hyperfocal distance is 40 meter, that means everything from 20 meters to infinity will be in acceptable focus (when printing.viewing at magnification of about 8 or 10). It seems unlikely you will be off in the distance** by so much that it matters--after all hyperfocal distance is meant to be approximate, and the the degree of unsharpness only changes gradually with distance.

If it really matters, likely you should close the lens down an additional stop, or rethink trying to get much depth of field, and just focus on what is most important.
____
** If your lens does not have distance markings that are adequate--just by eye (estimate w/o the camera) pick something that is the desired hyperfocal distance away--and focus the lens on that.

Last edited by dms; 09-01-2016 at 09:33 PM. Reason: Added footnote (**)
09-01-2016, 10:42 PM - 1 Like   #3
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QuoteOriginally posted by Steve Belcoski Quote
Can HFD be used for longer focal length lenses or is it really just for shorter focal lengths and if it can used with longer focal lengths, an HFD is known by app or calculation, how do you know, to the required accuracy, where that is when you are focusing on it?
Yes, the rules for DOF and HFD work the same for all focal lengths, though the concept is somewhat less useful as focal lengths increase. Here are few considerations:
  • There is nothing magical or even particularly special about the so-called hyperfocal distance. It is merely the plane of focus where the far DOF is sufficiently distant that your eye can't tell where the focus boundary is.
  • If you are worried about near DOF, don't use HFD as the basis for focus. That is a hard rule and why HFD is usually more useful at shorter focal lengths.
  • If you are not worried about far DOF, don't use HFD as the basis for focus
  • If the gradations on the distance scale are too far apart to zone focus HFD for your intended focal length and aperture, it is probably not a good time to use HFD
  • Very few people actually use HFD. Deep DOF with plane of focus at the intended subject is more useful. If the near field is important, the eye will forgive and may actually expect an unsharp far field.
  • Near field sharpness is ultimately more important than far and near DOF will usually fail in that respect. After all, there is only ONE plane of critical focus. The boundaries of near and far DOF merely describe the limits within which there is "acceptable" (not too soft) focus.
  • Your DOF calculator is your friend and knowing approximate DOF for your subject distance is more useful in planning the shot than precise attainment of HFD
  • Extreme near/far with appropriate proportions and optimum resolution is not possible without some form of camera movements and/or some form of focus stacking. With fixed lens axis and focal plane, the laws of optics, perspective, and perception work against you.
Do I ever use HFD? Yes, sometimes, though never for where focus is critical. Do I ever do something similar? Absolutely! Street photography is based on use of a moderate wide angle lens at f/8 with focus set to 2.5-3m. The combination provides about 5 meters of usable DOF. Frame-shoot-smile.


Steve
09-02-2016, 06:50 AM   #4
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Thank you for responding. I will take my time to digest all the iformation and I will take any opinions regarding photographic techniques that I have googled with a grain of salt. There is no emphasis placed on this by Bryan Peterson or that funny guy who schills for BH so I'll just stick to the books I've purchased. As for street photography, I don't understand why everybody and his brother can snap shots anywhere anytime with a cell phone but use a DSLR and then there's mass paranoia who are you, what you doing so I avoid it and sacrifice a lot of artistic opportunities. Besides, the aren't any streets where I live.

09-02-2016, 08:37 AM   #5
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QuoteOriginally posted by Steve Belcoski Quote
but use a DSLR and then there's mass paranoia who are you, what you doing so I avoid it and sacrifice a lot of artistic opportunities.
I don't shoot street very often, but when I do I generally use vintage gear and/or a rangefinder camera. I also prefer to engage with the people, after the shot if not before. If using the K-3, a small prime is less intimidating.

QuoteOriginally posted by Steve Belcoski Quote
Besides, the aren't any streets where I live.
Lucky you! In another life, I lived in a place where roads were few and trails and the water were the preferred modes of getting around.


Steve
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