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Thread: Hyperfocal distance and DOF experiment

  1. #11
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    Re: Hyperfocal distance and DOF experiment



    Try manual focusing on the hyperfocal distance using your distance scale. AF doesn't always hit the right spot.

  2. #12
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    Re: Hyperfocal distance and DOF experiment



    when you are hyperfocal distance focusing you are placing the focal point on a subject matter. What this means is that obviously there is DOF in front and behind your focal plane. However, the calculation alone will not gurantee perfections in the lens opticals and what you are doing is placing too much demand on the lens at that aperture.


    I would have used live view if i were you, and then focused on the tree, this would help with focus to begin with.


    I woul also stop down the lens to F/8 or F/11.





    What you also need to realize is that, at the far ends of the DOF buffer, that resolution is lost you aren't resolving as much. However, when viewing the print "normally" the background trees appear as sharp and within the DOF.





    I believe if you stopped down to F/8 or F/11 you would see a noticable increase in the resolved trees.





    FOcus on car @ F/2.8








    aperture down to 4.0








    Aperture to 5.6








    Aperture to 8








    While my focus did not change at all, I left all of that stationary, I did stop down my apertures and you will see how the items in the rear are better resolved. However, you just can't expect that great of a performance at F/4.

  3. #13
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    Re: Hyperfocal distance and DOF experiment



    Also the following scenes are with the 17-40 L on an XSi


    THe slices are full size and taken from images that look like this:











    F/8





    F/11





    F/16








    I believe this shows the other side of the Hyperfocal problem, where you resolve better at F/8 and the narrower you go, the more your image suffers from diffraction at 100% views.

  4. #14
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    Re: Hyperfocal distance and DOF experiment



    The impression I got from Alan's post was not how to maximize DOF through hyperfocal technique, but rather, how to determine the hyperfocal distance for a given f-number and focal length. Therefore, the calculation demonstrates three principles: first, that the determination of the hyperfocal distance is sensitive to the CoC which in turn is dependent on the viewing conditions of the image; second, that the commonly stated CoC of 0.03mm for 35mm format is not suitable for 100% crop on a 5DmkII, as this corresponds to a particularly high enlargement ratio due to high pixel density; and third, that it is ideal to not have to determine these things empirically at the time of capture, and that simply stopping down is not the relevant approach for understanding this subject.

  5. #15
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    Re: Hyperfocal distance and DOF experiment



    Thats fine.


    If he used a relevant COC such as .019 he would have found:


    <span style="word-spacing: 0px; font: 16px 'times new roman'; text-transform: none; color: #000000; text-indent: 0px; white-space: normal; letter-spacing: normal; border-collapse: separate; orphans: 2; widows: 2; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="Apple-style-span"]<span style="font-size: 11px; font-family: Arial;" class="Apple-style-span"]



    <table summary="results of depth of field calculation" width="100%" style="padding: 4px;" class="resultsTable"]
    <tbody>
    <tr>
    <td width="55%" align="left" valign="top" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Subjectdistance</td>
    <td name="resultsDistance" align="left" valign="top" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="resultsDistance" class="textClassResults"]16ft</td>
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    <tr>
    <td colspan="2" align="top" style="padding: 1px;"]
    </td>
    </tr>
    <tr>
    <td colspan="2" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Depthoffield</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; text-indent: 20px; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Nearlimit</td>
    <td name="dofNear" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="dofNear" class="textClassResults"]9.75ft</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; text-indent: 20px; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Farlimit</td>
    <td name="dofFar" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="dofFar" class="textClassResults"]44.5ft</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; text-indent: 20px; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Total</td>
    <td name="dofTotal" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="dofTotal" class="textClassResults"]34.7ft</td>
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    <tr>
    <td colspan="2" style="padding: 1px;"]</td>
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    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; text-indent: 20px; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Infrontofsubject</td>
    <td name="dofFront" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="dofFront" class="textClassResults"]6.2ft (18%)</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; text-indent: 20px; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Behindsubject</td>
    <td name="dofRear" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="dofRear" class="textClassResults"]28.5ft (82%)</td>
    </tr>
    <tr>
    <td colspan="2" style="padding: 1px;"]</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Hyperfocaldistance</td>
    <td name="hyperFocal" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="hyperFocal" class="textClassResults"]24.9ft</td>
    </tr>
    <tr>
    <td style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" class="textClassResults"]Circleofconfusion</td>
    <td name="cocused" align="left" style="font-weight: bold; font-size: 12px; margin: 0px 5px 5px; color: black; font-family: Verdana, Arial, sans-serif; padding: 1px;" id="cocused" class="textClassResults"]0.019 mm</td>
    </tr>
    </tbody>
    </table>






    Therefore, I advise consider stopping down to be with in the performance specifications he desired for his IQ.

  6. #16
    Alan
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    Re: Hyperfocal distance and DOF experiment



    I don't necessarily want to resurrect this discussion, but I found this article informative.


    http://www.trenholm.org/hmmerk/DOFR.html


    He says that if you focus at the hyperfocal distance, the background will be disappointingly blurry.


    With my experiment, this is what I found, as well.


    He doesn't believe in the "old story" of focusing at the hyperfocal distance.


    I think that I might do better by using Photoshop, and focus stacking two images, than taking chances with hyperfocal distance experiments.

  7. #17
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    Re: Hyperfocal distance and DOF experiment



    Quote Originally Posted by Alan
    He says that if you focus at the hyperfocal distance, the background will be disappointingly blurry.

    He's doing it wrong. The "old standards" for hyperfocal distance (like the ones printed on lens barrels) are based on small print sizes and low resolutions. These days we view images at 100% on the monitor up close, which simulates a print size of 6 feet wide. The hyperfocal distance varies by the acceptably sharp CoC, which is smaller for 100% crop viewing than it is for a 8x10 print, for example.

  8. #18
    Alan
    Guest

    Re: Hyperfocal distance and DOF experiment



    Well, if that's the case, I'll try it again.


    Maybe it's worth focusing (no pun intended) on f/8 (which is mostly where I'd use the camera for landscapes, anyway), then experiment around the theoretical hyperfocal distance, then just print some images to see how it goes.

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