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Thread: How to gauge aperture to use?

  1. #1

    Default How to gauge aperture to use?

    Hello to all, I'd like to ask how do you gauge what aperture settings to use when taking a photo? Especially so for a landscape photo or a group photo, what kind of settings do you usually use?

    I normally shoot in aperture priority mode, and I try to vary the aperture according to the DOF I need. However, I'm not sure what aperture settings to use when I take a group photo. Do I have to set it to F8 or smaller?

    How about for landscapes? I understand that to get more detail you set it to the smallest aperture. However, sometimes when I review the works of others, I find that they only use F8 or up to F12 only.

    And sometimes, for portrait they use only F2.8 and a large portion of the picture is relatively clear. I've thought about it and come up with some possible explanations, but I might not be correct. I think that 1) they are standing further away, or 2) they cropped the picture.

    Anyone can enlighten me on how you guage what kinds of aperture you use? Thanks!

  2. #2
    Moderator ortega's Avatar
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    Default Re: How to gauge aperture to use?

    the choice of aperture will normally depend on the amount of DOF you want

    now you need to find out on your setup how to get the desired DOF

    Factors:
    1. Focal lenght
    2. camera to subject distance
    3. aperture used
    4. sensor size

    have fun!

  3. #3
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by yuanseng1983 View Post
    Hello to all, I'd like to ask how do you gauge what aperture settings to use when taking a photo? Especially so for a landscape photo or a group photo, what kind of settings do you usually use?

    I normally shoot in aperture priority mode, and I try to vary the aperture according to the DOF I need. However, I'm not sure what aperture settings to use when I take a group photo. Do I have to set it to F8 or smaller?

    How about for landscapes? I understand that to get more detail you set it to the smallest aperture. However, sometimes when I review the works of others, I find that they only use F8 or up to F12 only.

    And sometimes, for portrait they use only F2.8 and a large portion of the picture is relatively clear. I've thought about it and come up with some possible explanations, but I might not be correct. I think that 1) they are standing further away, or 2) they cropped the picture.

    Anyone can enlighten me on how you guage what kinds of aperture you use? Thanks!
    I believe you know some theories about DoF:
    - Wide angle lenses give wider DoF than Tele angle lenses.
    - Long distance subject will give wider DoF than short distance subject.
    - Smaller aperture will give wider DoF than bigger aperture.
    - (There is CoC to consider DoF, but if you only use 1 camera, you can forget it for now).

    Easier thing is to set your camera to Auto Mode, or program mode like landscape, portrait, sport, etc. if your camera have it.

    Regards,
    Arto.

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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by ortega View Post
    the choice of aperture will normally depend on the amount of DOF you want

    now you need to find out on your setup how to get the desired DOF

    Factors:
    1. Focal lenght
    2. camera to subject distance
    3. aperture used
    4. sensor size

    have fun!
    Wah, so fast .

    Regards,
    Arto.

  5. #5
    Moderator ortega's Avatar
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by Artosoft View Post
    Wah, so fast .

    Regards,
    Arto.
    i know by heart already, so don't need to think so hard

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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by ortega View Post
    i know by heart already, so don't need to think so hard
    .

    Regards,
    Arto.

  7. #7
    Senior Member zac08's Avatar
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by yuanseng1983 View Post
    Hello to all, I'd like to ask how do you gauge what aperture settings to use when taking a photo? Especially so for a landscape photo or a group photo, what kind of settings do you usually use?

    I normally shoot in aperture priority mode, and I try to vary the aperture according to the DOF I need. However, I'm not sure what aperture settings to use when I take a group photo. Do I have to set it to F8 or smaller?

    How about for landscapes? I understand that to get more detail you set it to the smallest aperture. However, sometimes when I review the works of others, I find that they only use F8 or up to F12 only.

    And sometimes, for portrait they use only F2.8 and a large portion of the picture is relatively clear. I've thought about it and come up with some possible explanations, but I might not be correct. I think that 1) they are standing further away, or 2) they cropped the picture.

    Anyone can enlighten me on how you guage what kinds of aperture you use? Thanks!
    It's up to you on how much DOF you wanna set for each picture. The focal point also plays a part.

    If you are going for full clarity at all depths, then the hyperfocal distance comes to mind, (i.e. f16 on a 24mm and 1.8m to focus at...)

    But if you are targetting only a portion of the picture, then it all depends on what the guys above have mentioned. Distance to subject, focal length, aperture used... At f2.8 when at close distance, of course there isn't much DOF to play with. But at a further distance, you may have a lil more to manipulate.

    Keep trying and you'll learn...
    Michael Lim
    My Flickr Site

  8. #8

    Default Re: How to gauge aperture to use?

    for landscape, use HYPERFOCAL!!!!!

  9. #9
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by jeanie View Post
    for landscape, use HYPERFOCAL!!!!!
    To use hyperfocal distance, first you need to set the aperture. Meaning you need to know and select best/correct aperture for landscape.

    http://en.wikipedia.org/wiki/Hyperfocal_distance

    Regards,
    Arto.

  10. #10

    Default Re: How to gauge aperture to use?

    Quote Originally Posted by yuanseng1983 View Post
    How about for landscapes? I understand that to get more detail you set it to the smallest aperture. However, sometimes when I review the works of others, I find that they only use F8 or up to F12 only.
    setting aperture is partly about managing trade-offs. many lenses get a little sharper when you use a smaller aperture than wide open. but when you get to very small apertures, the effects of diffraction really start to set in, and then the picture starts to lose sharpness.

    most lenses are usually at their optimum sharpness by the time you reach f8 or f11. unless i really need to slow down the shutter speed, or increase the depth of field (e.g. macro shots), i prefer to use f8 or f11.

    quite a lot of landscape shots you don't need super depth of field, cos you're shooting at infinity. similarly with group shots, ppl tend to line up in 2 rows, along the same focus plane, so no need super super small aperture also. and if you're using a wide angle lens, the depth of field is so great that at f8, you can already set a hyperfocal length of about 2+m and get most of the frame in focus.

    basically, don't assume that for landscape and group pix, the smallest aperture is the best aperture...
    Black lens, white Lens, can take picture is a Good lens

  11. #11

    Default Re: How to gauge aperture to use?

    From what I know, the "best aperature", or I should say the aperature the lens perform best is the aperature in between the max and min aperature size... (which happens to be somewhere f8 to f12)

    But what I don't understand is how people able to get very sharp pictures using the 50mm f1.8 with aperature wide open? I have the same lens, but mine was very soft... I had to go to f4 to be sharp...
    I am NOT a PROfessional photographer and photography is NOT my hobby

  12. #12

    Default Re: How to gauge aperture to use?

    Just adding to what Pai said.

    From what I read previously, at what aperture diffraction starts to become noticeable to human eyes depends on the sensor size and picture size and viewing distance. (Something to do with Circle of Confusion vs the image blemishes formed by using a very small aperture).

    For a 1.5x crop factor DSLR and printing up to 12x8 inches at usual picture viewing distance, diffraction becomes perceptible by the human eyes when aperture goes beyond F/13 or thereabout.

    Because of the above and the fact that one could easily get the necessary very wide DOF at F/8-F/13 with focus at either infinity or hyperfocal distance (usually at just over 2m or so) with relatively short focal length (20-35mm usually used for landscape), people use F/8-F/13 for landscape for their APS sensor DSLRs.
    Last edited by Clockunder; 15th November 2006 at 07:36 PM.

  13. #13

    Default Re: How to gauge aperture to use?

    Thanks for all the replies! I'll keep all these in mind when taking my photos next time. Anyway, Can anyone explain a lil more on hyperfocal?

  14. #14
    Senior Member zac08's Avatar
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by yuanseng1983 View Post
    Thanks for all the replies! I'll keep all these in mind when taking my photos next time. Anyway, Can anyone explain a lil more on hyperfocal?
    Read this thread :

    Hyperfocal distance
    Michael Lim
    My Flickr Site

  15. #15

    Default Re: How to gauge aperture to use?

    Man... this is overwhelming... gotta go shoot shoot shoot!!!

  16. #16
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by yuanseng1983 View Post
    Thanks for all the replies! I'll keep all these in mind when taking my photos next time. Anyway, Can anyone explain a lil more on hyperfocal?
    Read my post #9.

    Regards,
    Arto.

  17. #17

    Default Re: How to gauge aperture to use?

    So I can shoot @ F2 when i use my 50mm F1.8?
    Then if I wanna get a larger DOF and retain sharpness, what's the next smaller Fstop number at this focal length? (actually I'm not sure if I'm speaking correctly, but that's what I understand from this thread)

  18. #18
    Senior Member zac08's Avatar
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    Default Re: How to gauge aperture to use?

    Quote Originally Posted by jeremyspk View Post
    So I can shoot @ F2 when i use my 50mm F1.8?
    Then if I wanna get a larger DOF and retain sharpness, what's the next smaller Fstop number at this focal length? (actually I'm not sure if I'm speaking correctly, but that's what I understand from this thread)
    At f1.8, the next full stop should be f2.5 ?

    But generally, I shoot at 1 stop smaller than f2.8 which is at f4 for a better DOF as well as a decent bokeh.
    Michael Lim
    My Flickr Site

  19. #19

    Default Re: How to gauge aperture to use?

    Quote Originally Posted by jeremyspk View Post
    So I can shoot @ F2 when i use my 50mm F1.8?
    Then if I wanna get a larger DOF and retain sharpness, what's the next smaller Fstop number at this focal length? (actually I'm not sure if I'm speaking correctly, but that's what I understand from this thread)
    For next F stop, multiply by a factor of 1.4142 (i.e. square root of 2).

    Read this thread : http://forums.clubsnap.org/showthread.php?t=217967

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