How did they get the blurring to be so much in this photograph?

Discussion in 'Digital Photography' started by waloshin, Mar 25, 2012.

  1. waloshin, Mar 25, 2012
    Last edited: Mar 25, 2012

    waloshin macrumors 68040

    waloshin

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    #1
    How did they get the background so blurred was it through photoshop or was it the lens?

    [​IMG]

    This is the most I could get for a blurred background from my camera. The blurring was done through the focus points.

    [​IMG]
     
  2. Phrasikleia macrumors 601

    Phrasikleia

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    #2
    Looks like pretty standard shallow depth of field to me. The typical result of a photo taken with a long focal length and a wide aperture.

    Edit: your cat photo wasn't showing when I first replied. If you want the kind of subject separation that you see in the photo of the XBox, you'll need a lens with a very wide maximum aperture, something like 100mm and f/2.
     
  3. waloshin thread starter macrumors 68040

    waloshin

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    #3
    Ok thanks i just love the way it looks.
     
  4. Rowbear macrumors 6502a

    Rowbear

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    #5
    Subject distance from the background + your distance from the subject all team up to make the top pic as blurry as it is.

    Your cat could have been taken at f/2.8, but because the other items are close to the cat, their details are more visible. The XBOX shot could have been taken at f/8, but because the BG is far away, it looks blurry.
     
  5. blueroom macrumors 603

    blueroom

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    #6
    It's impossible to blur the background with a small point & shoot camera with a small sensor even with a large aperture.

    Sony has a background defocus on their small sensor P&S cameras (takes two photos one in focus the other not and merges them in camera)

    A micro 4/3 camera has some DoF control, an APC-S more and a full frame sensor it's no problem.

    It's the main reason I switched to a Sony NEX camera over my Canon S90
     
  6. MacNut macrumors Core

    MacNut

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    #7
    Don't 4/3 cameras by default give you better dof?
     
  7. robbieduncan Moderator emeritus

    robbieduncan

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    #8
    How can DoF be better? It's either shallower or deeper. Neither is better.
     
  8. MacNut macrumors Core

    MacNut

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    #9
    Let me rephrase, being a crop sensor isn't it naturally deeper.
     
  9. elmo151 Guest

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  10. robbieduncan Moderator emeritus

    robbieduncan

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    #11
    For the same composition with the same f-stop selected? The way I understand it yes as you have to have a shorter focal length to get the same composition compared to full-frame. But the same focal length lens shot at the same focus distance with the same f-stop will have the same DoF field regardless of sensor size: the crop camera will simply have cropped the centre section of the full 35mm frame.
     
  11. fpnc, Mar 26, 2012
    Last edited: Mar 26, 2012

    fpnc macrumors 68000

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    #12
    That's not completely true. You can get blurred backgrounds even with an iPhone 4S and its sensor is TINY compared to most point-and-shoot cameras. You can't get extreme results with the iPhone, but just look at these pictures from Apple's website:

    http://www.apple.com/iphone/built-in-apps/camera.html#zoomerlay-gallery3

    http://www.apple.com/iphone/built-in-apps/camera.html#zoomerlay-gallery6
     
  12. fpnc, Mar 26, 2012
    Last edited: Mar 26, 2012

    fpnc macrumors 68000

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    #13
    That's very true. In any case, apparent DoF is a somewhat subjective measure of defocus as in a practical sense it also depends upon the magnification (rescaling) of the final image. If you view an image at a very small scale it will look relatively sharp regardless of the DoF. However, if you make a large print (or view it at a large size) then any defocus will become more apparent.
     
  13. Phrasikleia macrumors 601

    Phrasikleia

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    #14
    Here is a handy calculator for working out these sorts of questions:

    http://www.dofmaster.com/dofjs.html

    If I read your scenario correctly, then you'll see it's not quite right. A different sensor size will mean a different CoC (circle of confusion), and that will affect the depth of field.
     
  14. waloshin thread starter macrumors 68040

    waloshin

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    #15
    The Cat picture was not taken with a small point and shoot. The camera was Nikon d40.
     
  15. blueroom macrumors 603

    blueroom

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    #16
    At what aperture? You need wide open to get those shallow DoF.
    DoF Calculator for various cameras

    I'm on the lookout for a 50mm f1.8 e-mount. That's a 75mm with the 1.5x crop factor.

    It should make a nice portrait lens.
     
  16. robbieduncan Moderator emeritus

    robbieduncan

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    #17
    Indeed. And you need different apertures to get the same depth of field too. 25mm f/1.0 at 10 feet on m43 has the same DoF (but not CoC) as a 5D MkII with a 50mm f/1.0 lens at 10 feet. And should have pretty much the same view as well I think.
     
  17. Ruahrc macrumors 65816

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    #18
    I'm not sure I totally agree. CoC values are to a certain degree arbitrary. Don't forget that CoC is also arguably more a function of the intended output, such as print size and viewing distance, than it is a function of the sampling resolution of the sensor. An appropriate CoC value for a billboard will be very different than for a high resolution fine art print, even if you shoot the picture with the same camera.

    In this regard, I think the dofmaster calculator is incorrect in that it defines a specific CoC for each camera model, and that between camera models with similar pixel pitch, the listed CoC is different (see the D80 with CoC of 0.02mm and D3x of 0.03mm, but in reality the pixel pitch of each is very similar, the only real difference being that the D80 is DX and the D3x is FF).
     
  18. waloshin thread starter macrumors 68040

    waloshin

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    #19
    55mm f/5.6

    And this one: [​IMG]

    At 35mm f/4.8
     
  19. Phrasikleia macrumors 601

    Phrasikleia

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    #20
    It sounds as though your understanding of the physics greatly exceeds mine, so I'm prepared to believe that dofmaster's calculator could be incorrect. I think its amounts for total depth of field are at least reasonably accurate, but perhaps when you get down to matters of inches or less, it becomes very difficult to tell.
     
  20. snberk103 macrumors 603

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    #21
    There are 3 (main) DoF controls... Two of which are linked, but not symmetrically....
    1) Aperture - Basic control.... You should know this one....
    However, these two (below) influence each other - but not equally....
    2) Focal Length - Longer lenses (telephotos) have less DoF.
    3) Distance - Getting closer also shortens DoF

    Standing close to your subject and using a wide angle lense will not produce the same DoF as standing further away and using a telephone lense... even if the framing of the subject is the same the aperture used is the same.

    I forget off the top of my head which combo produces the shallower DoF. IIRC the D40 doesn't have a DoF preview button, so you will need to actually take the photos to figure it out....

    Luck.
     
  21. simsaladimbamba

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    #22
  22. BiteMyApple macrumors member

    BiteMyApple

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    #23
    It will always amaze me that thread starters get thumbed down for asking a legitimate question...
     
  23. simsaladimbamba

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    #24
    It is the same with some posts containing valid information. Since FacialBuuk does not offer "Not Like" buttons, they have to go somewhere, one of those places is MR.
    And waloshin is sometimes just disliked for starting so many threads, though they have become more sane than they were two, three years ago.
     
  24. blueroom, Mar 26, 2012
    Last edited: Mar 26, 2012

    blueroom macrumors 603

    blueroom

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    #25
    And for those who want to know why you simply can't shrink down sensor...
    Depth of field
    The mind numbing diffraction & sensor article

    PS Waloshin, your appear to be using the kit lens 18-55; which is a good all around lens but not a very fast lens f/3.5 at it's fastest and only at 18mm, at 50mm it's f/5.6. Do you have any other lenses? A 50mm f/1.8 is a nice fairly fast lens, a prime (usually sharper than a zoom) will give you more control over DoF.
    http://www.kenrockwell.com/nikon/5018daf.htm

    50mm is a popular lens, so much so there is a Toronto 50mm only photography meetup group.
     

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