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Thread: Exposure time

  1. #1

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    Exposure time

    Nikon D3100
    ISO 400
    1/400
    f5.6
    200mm

    Exposure time

    Should I use a higher speed to get better definition without affecting the water soft appearances?

  2. #2

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    Re: Exposure time

    In this case, probably yes (looking at the water droplets). The image doesn't look particularly sharp, but on this occasion I suspect that it's probably more lack of sharpening than it is motion blur or lack of Depth of Field.

    As a rule, high ISO noise (from using a high ISO setting) will degrade an image a lot less than motion blur or lack of depth of field. As an example, here's one I took at 1/4000th .

    Exposure time

  3. #3
    Moderator Dave Humphries's Avatar
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    Re: Exposure time

    Hi Javier,

    Yes, I would aim for over 1/1000s, my shots span 1/750 to 1/4000s - because I still leave it in aperture priority mode to ensure no surprises in exposure (e.g. when it can't "open up" anymore).

    The soft (or glassy/reflective) water effect on shots like yours can often times be enhanced by any noise reduction put in to combat the higher iso. Ideally, you'd want a bit less on the bird itself though, or it risks destroying feather detail - it all depends how your noise reduction works - I use Neat Image which samples an area of image (which I place on a 'blank' bit of water) then subtracts that noise 'signature' from all over the picture.

    Cheers,

  4. #4

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    Re: Exposure time

    Quote Originally Posted by Dave Humphries View Post
    Hi Javier,

    Yes, I would aim for over 1/1000s, my shots span 1/750 to 1/4000s - because I still leave it in aperture priority mode to ensure no surprises in exposure (e.g. when it can't "open up" anymore).

    The soft (or glassy/reflective) water effect on shots like yours can often times be enhanced by any noise reduction put in to combat the higher iso. Ideally, you'd want a bit less on the bird itself though, or it risks destroying feather detail - it all depends how your noise reduction works - I use Neat Image which samples an area of image (which I place on a 'blank' bit of water) then subtracts that noise 'signature' from all over the picture.

    Cheers,
    I practiced today with this new shot at:
    1/1600
    ISO 400
    f/5.6
    200mm
    Exposure time
    I believe; looks better.
    Comments…

  5. #5
    Moderator Dave Humphries's Avatar
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    Re: Exposure time

    Quote Originally Posted by Jleon99 View Post
    I practiced today with this new shot at:
    1/1600, ISO 400, f/5.6, 200mm
    Exposure time
    I believe; looks better.
    Comments…
    The problem is, it is focused about a foot in front of the bird
    The only sharp parts are the ripples right at the front, everything else is progressively softer.

    It's just a focus error though, others taken today may not have the problem, especially if Auto focus was used.

    But yes, the shutter speed and hence drop shapes, are definitely better.

  6. #6
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    Re: Exposure time

    Sometimes this happens to me also. My target gets blurred because the camera focused somewhere else near it.
    I think it is because of the focus speed (not so fast in my 55-200 VR lens) and the moving target.

    Is there any technique or aproach for a better focusing?
    How can we practice this?

    Thanks

  7. #7
    Moderator Dave Humphries's Avatar
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    Re: Exposure time

    Quote Originally Posted by Nuno View Post
    Sometimes this happens to me also. My target gets blurred because the camera focused somewhere else near it.
    I think it is because of the focus speed (not so fast in my 55-200 VR lens) and the moving target.

    Is there any technique or aproach for a better focusing?
    How can we practice this?

    Thanks
    I'm not familiar on how different the D3100 is from my D5000 Nuno, but here what I'd set (plus notes);

    AF-C (continuous AF) mode
    Single focus point (select which one using cursor pad after a half press of shutter button)
    Lens on "M/A" (not M) mode - but also make sure a (gloved?) hand isn't touching against the focus ring - if you move it, it will stop AF until you release and repress the shutter button
    VR "On" and in "Normal" (not Active) mode

    Good luck,
    Last edited by Dave Humphries; 30th December 2010 at 10:10 PM. Reason: updated

  8. #8
    Nuno's Avatar
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    Re: Exposure time

    Quote Originally Posted by Dave Humphries View Post
    I'm not familiar on how different the D3100 is from my D5000
    I have a D5000 too, and I think it is the same on the D3100. Thanks

  9. #9

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    Re: Exposure time

    Single point focus is the ONLY way to go in situations like this (I have my camera set to a single AF point approx 100.000% of the time)!

    (just like Dave said)

  10. #10
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    Re: Exposure time

    Well, obviously, having an AF-S/USM lens can help speed up your AF time. For me, getting a USM supertele was a serious eye-opener when it came to bird-in-flight shots. Also, if you have a focus limit switch on your lens use it--it's there to help you speed up AF lock by telling the lens to only search for AF through a specific distance range.

    One more autofocus technique that may help you is learning to do back-button autofocus (the page is for Canon cameras, but it works pretty much the same on Nikons)--this is where you separate the AE and AF behavior of the camera by assigning one or the other to one of the buttons on the back of the camera, rather than the shutter button half-press. Depending on your camera, it can require multiple custom function settings, but it's definitely worth knowing this option exists and why you might want to use it. With a camera that can store custom modes, it's particularly handy for turning a feature like this on and off.

    I use it with the AF assigned to the back button and start/stop behavior reversed (I.e., I half-press the * button on my camera when I want the camera to hunt for focus, and release the button to lock focus). The shutter button half-press is for metering only.

    I think the main thing is to pay attention to whether or not you've actually achieved focus lock on what you want before you take the photo. It's frustrating to have to let a shot go, but it's better to confirm via the viewfinder/AF confirmation/whathave you that you've got a clear shot first, rather than waste the valuable AF-hunting time on a shot that you know will be blurry. It can be hard to tamp down the adrenalin and not just spray'n'pray in hope, but the whole short-controlled bursts and good timing thing are key.

    Exposure time
    Canon 50D. EF 400mm f/5.6L USM. iso 800, f/5.6, 1/640s.
    Whited-Tailed Kite, juvenile. (Elanus leucurus)

  11. #11

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    Re: Exposure time

    Quote Originally Posted by Dave Humphries View Post
    I'm not familiar on how different the D3100 is from my D5000 Nuno, but here what I'd set (plus notes);

    AF-C (continuous AF) mode
    Single focus point (select which one using cursor pad after a half press of shutter button)
    and I'm sure there's a third option that I can't remember - I'll add it tonight when I have camera to hand
    Lens on "M/A" (not M) mode - but also make sure a (gloved?) isn't touching against the focus ring - if you move it, it will stop AF until you release and repress the shutter button
    VR "On" and in "Normal" (not Active) mode

    Good luck,
    Thank you; I got it.

  12. #12
    Moderator Dave Humphries's Avatar
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    Re: Exposure time

    Quote Originally Posted by Colin Southern View Post
    Single point focus is the ONLY way to go in situations like this (I have my camera set to a single AF point approx 100.000% of the time)!
    Ditto (just like Colin said)

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