12mm, f/2.8 non-OS vs. 24mm, f/4 OS

Discussion in 'Photography Beginners' Forum' started by raptorman, Apr 17, 2009.

  1. raptorman

    raptorman TPF Noob!

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    This may sound like a strange question, but anyway: you have to following hypothetical situation:

    There's an object I want to photograph and there's not too much light. Focal length is 24mm, optimal shutter speed is 1/6, aperture is f/4. Thanks to the image stabilization it's possible here to take in most cases an unblurren picture. Now I switch to a lens that allows f/2.8 @ 12mm, but without image stabilization. Now I take a picture of the same object, same light conditions, but I move closer to it, so it'll have the same size on my picture. Due to the larger aperture I can lower my shutter speed to 1/12. Due to the shorter focal lenght this should also result in an unblurren picture. Now my question is, is my way of thinking correct, will I get pretty much the same results taking that picture @12mm, f/2.8, 1/12 and @24mm, f/4, 1/6 OS?
     
  2. dcclark

    dcclark TPF Noob!

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    All that really matters for blurred vs. not blurred is your shutter speed. (This is ignoring whether you will have enough depth of field with the different apertures, but I'm assuming you can focus on the object you want and have as much of it as you want in focus.)

    The typical rule is that you need 1/(focal length) for your shutter speed, to avoid blur due to shake. OS/stabilization/VR/IS/whateveryouwanttocallit will reduce this, so in your case you'll be right on the edge.

    So, 1/12 second may cause some blur without stabilization. I know that I have trouble getting a sharp shot without VR (Nikon's equivalent of OS) at those speeds, but being ultra-wide, you may not notice it.
     
  3. epp_b

    epp_b No longer a newbie, moving up!

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    12mm is such an extremely wide angle that you'll have enormous depths of field with, even at wide apertures like f/2.8. The main factor that effect depth of field at this focal length is focus distance.

    Wide angles like this are also much easier to hand-hold at quite slow shutter speeds than normal and telephoto lengths. IS/OS/VR becomes a useful luxury and wide angles rather than the near-necessity it is at telephoto lengths.

    Yes and no. Wide angles cause (intentional) perspective distortion. The wider the focal length, the more the distortion. Even if you have the subject fill the frame exactly the same at each focal length, the results from each focal length will look different because of this effect.
     
    Last edited: Apr 17, 2009

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