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Thread: Need help on understanding hyperfocal distance.

  1. #21
    Moderator ziploc's Avatar
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by tecnica View Post
    i usually manual focus to ~1 or 2m(depending on lens) ahead of me, min f8 to ensure dof covers till infinity.
    That is actually not enough. Assuming your camera has a 1.5x crop factor and a CoC of 0.02mm, with 50mm focal length and f/8, the hyperfocal distance is about 15.7m, and focusing at 2m gives DOF far field of only 2.29m. If you're at 28mm and f/8, the hyperfocal distance is about 4.93m, and at 2m the DOF far field is 3.35m. Only when you get below 18mm focal length will the far field lies beyond infinity. Focusing at 1m will only make it worse.
    Last edited by ziploc; 25th April 2011 at 11:47 PM.

  2. #22
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by ziploc View Post
    That is actually not enough. Assuming your camera has a 1.5x crop factor and a CoC of 0.02mm, with 50mm focal length and f/8, the hyperfocal distance is about 15.7m, and focusing at 2m gives DOF far field of only 2.29m. If you're at 28mm and f/8, the hyperfocal distance is about 4.93m, and at 2m the DOF far field is 3.35m. Only when you get below 18mm focal length will the far field lies beyond infinity. Focusing at 1m will only make it worse.
    This is really when you really need a DOF calculator... The math part is making me blur... At least I know the CoC portion will makes too much of a difference even if I miss it by a bit....

  3. #23
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by ziploc View Post
    That is actually not enough. Assuming your camera has a 1.5x crop factor and a CoC of 0.02mm, with 50mm focal length and f/8, the hyperfocal distance is about 15.7m, and focusing at 2m gives DOF far field of only 2.29m. If you're at 28mm and f/8, the hyperfocal distance is about 4.93m, and at 2m the DOF far field is 3.35m. Only when you get below 18mm focal length will the far field lies beyond infinity. Focusing at 1m will only make it worse.
    hmmm....Not sure if you mind explaining abit on...If lets say I'm taking a scenery of mountain, rivers etc. All/most subjects are quite far away (and I don't know the distance), how would I get a sharp shot of the picture?

    Image from: http://explorehimalyas.com/wp-conten...l_mountain.jpg

    *this picture is to illustrate the kind of scenery I want to take, and is not shot by me*

    In this scenario, how would you advice me to shoot this image? Normally what I will be doing is focus at f8 at the trees then recompose again (if needed), but many times my background will be alittle off focus. Am I doing anything wrong?
    Too many great equipments but too little quality photos. [My Flickr] | [My Blog]

  4. #24
    Moderator ziploc's Avatar
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by SkyStrike View Post
    hmmm....Not sure if you mind explaining abit on...If lets say I'm taking a scenery of mountain, rivers etc. All/most subjects are quite far away (and I don't know the distance), how would I get a sharp shot of the picture?

    In this scenario, how would you advice me to shoot this image? Normally what I will be doing is focus at f8 at the trees then recompose again (if needed), but many times my background will be alittle off focus. Am I doing anything wrong?
    The simplest way to shoot landscape when all or most subjects are far away is to focus near infinity (focus on a subject that is farthest away). This is in fact what most people are doing, which is fine, but it won't give you the maximum DOF attainable under f/8. A good landscape (like the example you have given) would usually have not only background (the mountain) but also interesting mid (the trees) and foreground (the reflection in the water). So in order to get everything (fore-, mid-, background) in focus, hyperfocusing will be needed.

    To shoot something similar to the example above, here are the steps I would take:

    1. Choose a focal length that can cover the composition.
    2. Choose an adequte f-stop, working down from f/16 to f/8 depending on available light and the desired DOF coverage. If the shutter speed drops below the 1/(focal length) rule of thumb, use a tripod + shutter string/timer.
    3. Lookup the hyperfocal distance for the selected focal length and f-stop, using either DOF or hyperfocal chart, or hand phone app.
    4. Manually turn the focusing ring on my lens to the hyperfocal distance with the aid of the distance scale. If the lens has no distance scale, focus on an object with an estimated distance slightly further away from the hyperfocal distance (you will lose some near DOF but will ensure the far DOF is beyond infinity).
    5. Take the shot.
    Last edited by ziploc; 26th April 2011 at 03:39 PM.

  5. #25
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by SkyStrike View Post
    [..]Normally what I will be doing is focus at f8 at the trees then recompose again (if needed), but many times my background will be alittle off focus. Am I doing anything wrong?
    You don't focus at your target aperture. Focusing is done wide open (maximum aperture), the camera will stop down once you press the shutter.
    EOS

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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by ziploc View Post
    The simplest way to shoot landscape when all or most subjects are far away is to focus near infinity (focus on a subject that is farthest away). This is in fact what most people are doing, which is fine, but it won't give you the maximum DOF attainable under f/8. A good landscape (like the example you have given) would usually have not only background (the mountain) but also interesting mid (the trees) and foreground (the reflection in the water). So in order to get everything (fore-, mid-, background) in focus, hyperfocusing will be needed.

    To shoot something similar to the example above, here are the steps I would take:

    1. Choose a focal length that can cover the composition.
    2. Choose an adequte f-stop, working down from f/16 to f/8 depending on available light and the desired DOF coverage. If the shutter speed drops below the 1/(focal length) rule of thumb, use a tripod + shutter string/timer.
    3. Lookup the hyperfocal distance for the selected focal length and f-stop, using either DOF or hyperfocal chart, or hand phone app.
    4. Manually turn the focusing ring on my lens to the hyperfocal distance with the aid of the distance scale. If the lens has no distance scale, focus on an object with an estimated distance slightly further away from the hyperfocal distance (you will lose some near DOF but will ensure the far DOF is beyond infinity).
    5. Take the shot.
    Thanks Ziploc for explaining, Points noted. Regarding the DOF, If my Focal Length is at 10mm, Aperture at f8, According to http://www.dofmaster.com/dofjs.html, my Hyperfocal distance is 0.67 m. So does this mean that I "measure"/guesstimate this ~67cm (prob I will end up with 1m) from the point which I'm standing?


    Quote Originally Posted by Octarine View Post
    You don't focus at your target aperture. Focusing is done wide open (maximum aperture), the camera will stop down once you press the shutter.
    Sorry, the way I phrased it was abit wrong...I meant to say that my aperture was set at f8 (so basically it's still wide open before the shutter is pressed all the way or the DOF button is pressed) and I recomposed after focusing at the target.
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  7. #27

    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by ziploc View Post
    That is actually not enough. Assuming your camera has a 1.5x crop factor and a CoC of 0.02mm, with 50mm focal length and f/8, the hyperfocal distance is about 15.7m, and focusing at 2m gives DOF far field of only 2.29m. If you're at 28mm and f/8, the hyperfocal distance is about 4.93m, and at 2m the DOF far field is 3.35m. Only when you get below 18mm focal length will the far field lies beyond infinity. Focusing at 1m will only make it worse.

    of cause' i know what i'm doing, like i said, depending on my lenses.

    shooting with my UWA at 10mm or 17mm with my standard zoom(16mm and 27.2mm in 35mm terms), 1 or 2m @ >f8 is enough to cover till infinity.
    Last edited by tecnica; 26th April 2011 at 11:35 PM.

  8. #28
    Moderator ziploc's Avatar
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by SkyStrike View Post
    Thanks Ziploc for explaining, Points noted. Regarding the DOF, If my Focal Length is at 10mm, Aperture at f8, According to http://www.dofmaster.com/dofjs.html, my Hyperfocal distance is 0.67 m. So does this mean that I "measure"/guesstimate this ~67cm (prob I will end up with 1m) from the point which I'm standing?
    You're most welcome. Yup that would be correct, the hyperfocal distance is short because the 10mm is an ultra wide angle. Focusing at 1m is actually good enough because anything from 0.5m to infinity will be "in focus". Normally it is actually better to focus slightly further than the calculated hyperfocal distance because that will ensure the DOF far field is beyond infinity.

  9. #29
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    Default Re: Need hElp on understanding hyper distance.

    Quote Originally Posted by ziploc View Post
    You're most welcome. Yup that would be correct, the hyperfocal distance is short because the 10mm is an ultra wide angle. Focusing at 1m is actually good enough because anything from 0.5m to infinity will be "in focus". Normally it is actually better to focus slightly further than the calculated hyperfocal distance because that will ensure the DOF far field is beyond infinity.
    Ah...now I understand. Many thanks!

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  10. #30
    Member bojee's Avatar
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    After reading through this thread I finally understand hyperfocal distance. Thanks guys.
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