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Thread: Teknik & Tips | Apa itu Bokeh?

  1. #1

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    Teknik & Tips | Apa itu Bokeh?

    brapa kali dah jumpa perkataan nie, "bokeh". tp tak tertanya. kali nie nak tanya gak. :mrgreen: ada jumpa penerangannye dlm mag Digital Camera, tp tak puas hati sgt dgn jawapannya.

    bole sesape terangkan, apa tu bokeh? bokeh yg macammana dikira baik dan macammana ia terjadi. terima kasih.

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  3. #2

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    ini yg boe dapat dari net...

    bokeh, from japanese boke, unsharp. The appearance of the out-of-focus areas of a photographic image. Also, the rendition of out-of-focus image areas by a particular lens, i.e. a lens with a pleasing out-of-focus rendition is said to have ‘good bokeh.’

    (Calling this type of bokeh ‘good’ and the opposite - a harsh background rendition - ‘bad’ is somewhat misleading, because ‘bad’ bokeh can in some situations look better. This is because the only slightly out-of-focus areas can appear sharper. But the usage has become fairly common now.)
    "I'm Not Alone When I'm With My D70"

  4. #3

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    WHAT IS BOKEH?

    Bokeh describes the rendition of out-of-focus points of light.

    Bokeh is different from sharpness. Sharpness is what happens at the point of best focus. Bokeh is what happens away from the point of best focus.

    Bokeh describes the appearance or "feel" of out-of-focus backgrounds and foregrounds.

    Differing amounts of spherical aberration alter how lenses render out-of-focus points of light, and thus their bokeh. The word "bokeh" comes from the Japanese word "boke" (pronounced bo-keh) which literally means fuzziness or dizziness.

    A technically perfect lens has no spherical aberration. Therefore a perfect lens focuses all points of light as cones of light behind the lens. The image is in focus if the film is exactly where the cone reaches its finest point. The better the lens, the tinier this point gets.

    If the film is not exactly where that cone of light reaches its smallest point, then that point of the image is not in focus. Then that point is rendered on film as a disk of light, instead instead of as a point. This disc is also called the "blur circle," or "circle of confusion" by people calculating depth-of-field charts. In a lens with no spherical aberration this blur circle is an evenly illuminated disc. Out of focus points all look like perfect discs with sharp edges. (OK, at smaller apertures where the image is in pretty good focus you may see additional "Airy" rings around the circle, but that's a diffraction pattern we're not discussing here.) This isn't optimal for bokeh, since as you can imagine the sharp edge of these discs can start to give definition to things intended to be out-of-focus.

    There are no perfect lenses, so one usually does not see these perfect discs.

    Real lenses have some degree of spherical aberration. This means that in practice, even though all the light coming through the lens from a point on the subject may meet at a nice, tiny point on the film, that the light distribution within the cone itself may be uneven. Yes, we are getting abstract here, which is why some denser photographers refuse to try understand bokeh.
    "I'm Not Alone When I'm With My D70"

  5. #4

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    Illustrations

    Spherical aberration means that the discs made by out-of-focus points on the subject will not be evenly illuminated. Instead they tend to have more of the light collect in the middle of the disc or towards the edges. Here are some illustrations:


    Fig. 1. Poor Bokeh. This is a greatly magnified blur circle showing very poor bokeh. Note how the edge is sharply defined and even emphasized for a point that is supposed to be out-of-focus, and that the center is dim.


    Fig 2. Neutral Bokeh. This is a a technically perfect and evenly illuminated blur circle. This isn't good either for bokeh, because the edge is still well defined. Out-of-focus objects, either points of light or lines, can effectively create reasonably sharp lines in the image due to the edges of the sharp blur circle. This is the blur circle from most modern lenses designed to be "perfect."


    Fig. 3. Good Bokeh. Here is what we want. This is great for bokeh since the edge is completely undefined. This also is the result of the same spherical aberration, but in the opposite direction, of the poor example seen in Fig. 1. This is where art and engineering start to diverge, since the better looking image is the result of an imperfection. Perfect bokeh demands a Gaussian blur circle distribution, and lenses are designed for the neutral example shown in 2.) above.
    "I'm Not Alone When I'm With My D70"

  6. #5

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    ni contoh yg boe ada.... kan blakang dia blur atau kita panggil bokeh...

    "I'm Not Alone When I'm With My D70"

  7. #6

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    oooo...cam tu ker cikgu boe........lagi blur lagi bagus ler tu ek cikgu...
    kerja?tidoq?melepak?merayau?mencari rezeki?mencari idea?

  8. #7

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    rasanya la...lagi bokeh..lagi cun gmbr tu....
    kita cuba tengok pendapat cikgu lain plak...
    "I'm Not Alone When I'm With My D70"

  9. #8

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    time kasih boe. panjang lebar dia bg.:mrgreen:

    tp boe... kalau cam contoh yg kau bg tu.. bukan DOF ke? rasanya... burung tu pun sharp kan? ikut text yg kau bg tu;
    Bokeh describes the appearance or "feel" of out-of-focus backgrounds and foregrounds..
    bukan maknanya... burung tu pun kena blur gak ke?

    hihi... sorry la... slow skit aku nih.

  10. #9

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    oooohhhh....bokehnnyaa (blurnya) aku ari niiee...kerja banyak!! :lol:

  11. #10
    rasenye Bokeh dgn DOF(depth Of Field) nih lebih kurang kot cuma bezanya bokeh nih ambik dr istilah jepon.. dalam istilah photographer sebutan 'bokeh' lebih mesra alam nak sebut jika dibandingkan dengan DOF (depth of field)

    *betulkan klau aku salah
    ________________________

    Depth of Field (DOF)
    With an understanding that COF is a human imposed parameter that varies according to the manufacturer's whim and the vagaries of human perception we can now look at what is meant by Depth of Field. This is strictly an optical phenomena; and once a COF is applied no discretion is allowed.

    Definition: "The area in front of and behind a focused subject in which the photographed image appears sharp".

    Now that we understand what Circle of Confusion means we can see that this definition of Depth of Field means that this is the range in front of and behind the subject focused on that will appear sharp within the limits of the applied COF. In other words, you can't have a DOF number without a COF number, and the COF number is one decided on by you or the lens manufacturer, whomever you trust the most.

    As a concrete example of all of this, a 50mm lens, focused on a subject 10 feet away, at an aperture of f/5.6, and using a COF of 30 lines / mm (0.0333mm), will have a near focus point of 8.17 feet and a far focus point of 12.88 feet. In other words, it will have a Depth of Field of 4.72 feet (12.88 - 8.17 = 4.72). Stop down to f/16 and the DOF becomes almost 22 feet.

    If you look at a DOF table, the DOF scale on a lens, or use a computer program to make the calculation, you'll see that one of the laws of optics is that the DOF extends from 1/3rd in front of the point focused on, to 2/3rds behind it. In other words, you have twice as much DOF behind your point of focus than in front of it.


    Tiger — Toronto, 2000


    sumber rujukukan http://www.luminous-landscape.com/tutor ... /dof.shtml
    "Great Photos Are Made, Not Taken"- Ansel Adam
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  12. #11

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    Quote Originally Posted by helmyemran
    time kasih boe. panjang lebar dia bg.:mrgreen:

    tp boe... kalau cam contoh yg kau bg tu.. bukan DOF ke? rasanya... burung tu pun sharp kan? ikut text yg kau bg tu;
    Bokeh describes the appearance or "feel" of out-of-focus backgrounds and foregrounds..
    bukan maknanya... burung tu pun kena blur gak ke?

    hihi... sorry la... slow skit aku nih.
    DOF atau deep of field ada dua...iaitu Limited DOF & Extended DOF...
    untuk gmbr bangun tu adalah extended Dof kerana imej yg hendak dirakamkan adalah sharp dan background nya adalah bokeh.. untuk limited dof pula.. imej dan background adalah sharp...tiada bokeh...

    itu yg boe paham...
    "I'm Not Alone When I'm With My D70"

  13. #12
    lagi banya bokeh, lagi wokeh!!

  14. #13

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    heehe...betul tu papa....
    "I'm Not Alone When I'm With My D70"

  15. #14
    bokeh itu bekas (dlm bahasa minang) thehehehe...tak caye tny org negeri 9...keh keh keh...tuh pasal kekadang den konpius bile photographer ckp bokeh bokeh....sbb tringat bhs minang..tp skg dah ok....cuma kene terkujat 6 saat utk pk ape itu bokeh...thehehehe... sekadar berkongsi..... p/s: helmy tuh memang lembab sket...kowang maafkan la dia ek? thehehe...walaupon begitu helmy, aku tetap sayang ko...wakakakakakkakaka.... (kantoi tak kalo weet baca? )
    ~tak hairanlah apabila kamu memberikan seseorang itu kayu untuk memukul ular di depannya tetapi dia memukul di kepalamu kerana itu adalah lumrah bagi manusia yang tidak bersyukur dan hati yang diterbalikkan Allah~

  16. #15

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    gerent kantoi ler antu........takper..buat2 tak namapk ejk....
    kerja?tidoq?melepak?merayau?mencari rezeki?mencari idea?

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