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Thread: aperture > f20

  1. #1

    Default aperture > f20

    1) i need shallower DOF to capture an object without blurring any part of it...is +/- f8 really enough? i have not seen anyone using > f20 yet...and is it abnormal to use?

    2) is using a flash a good practice to shoot at smaller aperture (even in outdoor)? my pictures are blurred without flash at f7 outdoor (using nikon VR lens).

  2. #2
    Moderator Octarine's Avatar
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    Default Re: aperture > f20

    1) Read this article: Understanding Depth of Field and follow the links given.
    2) Please describe your setup and the condition (time, light etc.) or post an example image with EXIF intact. Everything else is just wild guessing based on a very vague description.
    EOS

  3. #3

    Default Re: aperture > f20

    1. Read on hyperfocal distance.
    2. Read up on diffraction. That's why I wouldn't go higher than f/16.
    Alpha

  4. #4

    Default Re: aperture > f20

    Hard to advise without critical details and specific samples with EXIF details.

    The reason why people ask for EXIF a lot of times is because authors too often miss out critical details, whereas it's all contained in the EXIF.

    Having said that, as for achieving DEEP (NOT shallow) DOF, using smaller apertures is one approach (with the necessary increase in ISO or amount of light or much longer shutter speeds, as appropriate).

    When a smaller aperture is used effectively with hyperfocal practice, it may sometimes help, or not. All depends on specific situations/subject/set-up etc etc etc

    Where critical quality and DOF control is required without worrying about diffraction degradation setting in, or when stopping down to the maximum is still not enough, one of the preferred approaches is to make use of the Scheimpflug principle (http://en.wikipedia.org/wiki/Scheimpflug_principle) via tilt/shift lenses or a large format camera. Applying the Scheimpflug principle in real life is actually easier than reading the wiki entry, but mastering it with critical control can be quite challenging.

    There is another technique that can be used. Does anyone know what it might be?

    As regards your second question, we must find out WHY your photos was blur. Adding a flash blindly may or may not help, but we won't be helping you much because whatever is said would be pure speculative hamtam bola tikam tikam in the dark.
    Last edited by Dream Merchant; 23rd October 2009 at 01:29 AM.

  5. #5

    Default Re: aperture > f20

    Quote Originally Posted by baggiolee View Post
    1) i need shallower DOF to capture an object without blurring any part of it...is +/- f8 really enough? i have not seen anyone using > f20 yet...and is it abnormal to use?

    2) is using a flash a good practice to shoot at smaller aperture (even in outdoor)? my pictures are blurred without flash at f7 outdoor (using nikon VR lens).
    i used f/22 a lot, usually to extend exposure. these days, usually don't go beyond f/16.

    you will get diffraction, but that is something that you compromise on.

    sometimes, i use f/22 for maximum depth of field. this is in particular when i want to use uwa (10-20 @ 10mm), and go very low. to retain maximum relative sharpness from front to back, have to stop down and go for focus at hyperfocal point.

  6. #6
    Deregistered shaoken's Avatar
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    Default Re: aperture > f20

    I use F16 and above for long exposure.
    I think F8-11 should be alright.

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    Default Re: aperture > f20

    Quote Originally Posted by baggiolee View Post
    1) i need shallower DOF to capture an object without blurring any part of it...is +/- f8 really enough? i have not seen anyone using > f20 yet...and is it abnormal to use?

    2) is using a flash a good practice to shoot at smaller aperture (even in outdoor)? my pictures are blurred without flash at f7 outdoor (using nikon VR lens).
    1. Its not abnormal to use f22 or even larger if you lens permits. Photos might be less sharp, but at normal viewing it shouldn't cause any issue in IQ. Pixel peeping might be another story. I have seen books where photographers used f/32 or even smaller.
    Erm, pardon me for asking, your statement a bit contradicting. You want shallower dof and yet you want to use f8 or even f/20? Normally f/2.8-f/5.6 or so should be able to give you a clear object w/o any blur part and yet have some background blur. Of course it is focal length dependent and subject dependent. f/20 and up is more for like say you have a flower in front of a mountain and you want to capture a photo where the flower is sharp and fill a decent part of the frame and yet you can see the landscape and mountain in the background.

    2. Something is not right. In bright outdoor, you should be able to shoot even f/22 using handheld and not suffer from hand shake blur. It shouldn't be a problem even w/o vr unless you are using a super long tele. Indoor is another thing though.

  8. #8

    Default Re: aperture > f20

    Quote Originally Posted by NewbieInCS View Post
    1. Its not abnormal to use f22 or even larger if you lens permits. Photos might be less sharp, but at normal viewing it shouldn't cause any issue in IQ. Pixel peeping might be another story. I have seen books where photographers used f/32 or even smaller.
    er, usually that is for medium format.

    f/32 for dslr is really going to give you kickass diffraction visible even at small sizes. believe me, i've tried.

  9. #9
    Moderator catchlights's Avatar
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    Default Re: aperture > f20

    Quote Originally Posted by NewbieInCS View Post
    1. Its not abnormal to use f22 or even larger if you lens permits. Photos might be less sharp, but at normal viewing it shouldn't cause any issue in IQ. Pixel peeping might be another story. I have seen books where photographers used f/32 or even smaller.
    ....................
    the smallest aperture on most lenses usable on DSLR is only f22. but using f22 on DSLR will have diffraction.

    I hardly use bigger than f11 on my Mamiya RB, usually f32, and usually use f45 on my large format camera. but that is on film.
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  10. #10

    Default Re: aperture > f20

    Quote Originally Posted by catchlights View Post
    the smallest aperture on most lenses usable on DSLR is only f22. but using f22 on DSLR will have diffraction.

    I hardly use bigger than f11 on my Mamiya RB, usually f32, and usually use f45 on my large format camera. but that is on film.
    my tamron 70-300 got f/45..

    but the softness is power!

  11. #11
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    Default Re: aperture > f20

    Yes I know that is mostly for mf.

    Yes, it will be softer, BUT not completely unusable right? A no meaning test shot at f/32 using a kit lens. Maybe you guys don't find it ok, but to me it is usable.
    http://www.flickr.com/photos/44010045@N08/4040682831/

  12. #12

    Default Re: aperture > f20

    Quote Originally Posted by NewbieInCS View Post
    Yes I know that is mostly for mf.

    Yes, it will be softer, BUT not completely unusable right? A no meaning test shot at f/32 using a kit lens. Maybe you guys don't find it ok, but to me it is usable.
    http://www.flickr.com/photos/44010045@N08/4040682831/
    of course not unusable, it's just that the performance has dropped exponentially to the point that most people would not deem it as acceptable image quality.

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    Default Re: aperture > f20

    I think you all have made it pretty clear why not to use f number more than f16.. so the question is how do I gain very deep DOF without using so small aperture?

    The solution is to do focus stack. This technique involves taking multiple shots at diff focus points, then digitally combining the shots together in PS. Can google to read more. I've been doing focus stack for macro, and it's the easiest way to achieve edge to edge sharpness without compromising on loss in detail.
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  14. #14
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    Default Re: aperture > f20

    arggh... i used F22 earlier today on my Ef 85 f1.8 to "darken" the white background... i realised that sharpness deteriorated quite badly after F16... next time i shall stick to f16 or f18 max.

  15. #15

    Default Re: aperture > f20

    Quote Originally Posted by ianhyk View Post
    I think you all have made it pretty clear why not to use f number more than f16.. so the question is how do I gain very deep DOF without using so small aperture?

    The solution is to do focus stack. This technique involves taking multiple shots at diff focus points, then digitally combining the shots together in PS. Can google to read more. I've been doing focus stack for macro, and it's the easiest way to achieve edge to edge sharpness without compromising on loss in detail.
    lol tats cool!! and tats what i need...i need more DOF, think i should skip 35/50mm 1.4/1.8 lens as well, since i need deeper DOF most of the time.

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    Default Re: aperture > f20

    Sorry to hijack this threat.

    Some of you use smaller f number for long exposure as I read the posts. May I know in what situation and for what effect when you go for > f16 and long exposure?

  17. #17
    Moderator catchlights's Avatar
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    Default Re: aperture > f20

    Quote Originally Posted by LBL2009 View Post
    Sorry to hijack this threat.

    Some of you use smaller f number for long exposure as I read the posts. May I know in what situation and for what effect when you go for > f16 and long exposure?
    you can get the effects of

    "or lu lu" or "pei liao liao" photos if you did not make the correct exposure

    a lot hand shake if you did not use tripod

    a lot of subject motion blur if this is what you looking for
    Last edited by catchlights; 27th October 2009 at 10:47 AM.
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  18. #18

    Default Re: aperture > f20

    Quote Originally Posted by LBL2009 View Post
    Sorry to hijack this threat.

    Some of you use smaller f number for long exposure as I read the posts. May I know in what situation and for what effect when you go for > f16 and long exposure?
    To capture silky water flow in daylight
    To capture moving clouds in daylight
    To make ppl dissapeared at busy street in daylight

    Btw you need ND for help

  19. #19
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    Default Re: aperture > f20

    Quote Originally Posted by chalib View Post
    To capture silky water flow in daylight
    To capture moving clouds in daylight
    To make ppl dissapeared at busy street in daylight

    Btw you need ND for help
    Get it. Thanks.

  20. #20

    Default Re: aperture > f20

    if you have something ND 10 or stronger, usually u can shoot at f/8. if you only have low ND filters then u have to go f/16 or smaller. don't forget your polarizer is worth 2 stops.

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