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Thread: Why f4.5 and why f16 ?

  1. #1
    stevenL
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    Default Why f4.5 and why f16 ?

    Ok. Newbie question here.

    Why do we take pictures at f4.5 or less? I understand its for DOF? that a smaller f means a shorter shutter time?

    Why at f16? Because we want the deeper DOF? then shuuter time has to increase?

    Is that the deciding factor?

  2. #2
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    Default Re: Why f4.5 and why f16 ?

    Originally posted by stevenL
    Ok. Newbie question here.

    Why do we take pictures at f4.5 or less? I understand its for DOF? that a smaller f means a shorter shutter time?

    Why at f16? Because we want the deeper DOF? then shuuter time has to increase?

    Is that the deciding factor?
    You are right... We choose a higher f stop, i.e. smaller aperture, so that the DOF is deeper.... When doing so, the shuttle speed has to increase.

    Note that DOF have 3 decising factors, aperture setting, focus length and subject to background distance. (Someone do correct me if I'm wrong)...

    So it all boils down to what are you trying to take...

    Hope this helps...

  3. #3

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    I hope you know that lenses are not equally sharp at all aperatures, usually f8 is the sharpest aperture for 35mm lenses.

  4. #4
    Moderator ziploc's Avatar
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    Default Re: Re: Why f4.5 and why f16 ?

    Originally posted by Kira

    Note that DOF have 3 decising factors, aperture setting, focus length and subject to background distance. (Someone do correct me if I'm wrong)...
    Don't forget about camera to subject distance too...

  5. #5
    stevenL
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    I was trying out macro photo using a D60 with 25mm extention tube with a 105mm len at f4.5

    Turn out that my pictures is great except that the DOF is very shallow. Certain part of the flower becomes out of focus.

    And later I read in this forum that macro shooting setting usually is at f11/f16. Which I think would give a deeper DOF but shutter speed has to decrease. Am I right?

  6. #6

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    Originally posted by stevenL
    And later I read in this forum that macro shooting setting usually is at f11/f16. Which I think would give a deeper DOF but shutter speed has to decrease. Am I right?
    Yes, you're right. You have to use tripod and flash if you need to.

  7. #7
    stevenL
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    Originally posted by Sgt. Pepper
    Yes, you're right. You have to use tripod and flash if you need to.
    Flash under broad day light?

    I am afraid it might over expose the pic. Also I would need a bracket then? :P

  8. #8

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    Originally posted by stevenL
    Flash under broad day light?

    I am afraid it might over expose the pic. Also I would need a bracket then? :P
    In broad daylight (not under the shade) you should be getting faster shutter speed even you use F11 or F16 at Av mode. Using normal lighting is always facinating for nature shots.

  9. #9
    stevenL
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    Originally posted by Sgt. Pepper
    In broad daylight (not under the shade) you should be getting faster shutter speed even you use F11 or F16 at Av mode.
    ...which the meter will tell me right?..

    I am trying to take pics which are in its natural setting. Kinda like a walk thru the jungle kinda thing.

  10. #10

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    Originally posted by stevenL
    ...which the meter will tell me right?..

    I am trying to take pics which are in its natural setting. Kinda like a walk thru the jungle kinda thing.
    anymore concern?

  11. #11
    stevenL
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    none.

    Thanks

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