Lens aperture setting

Discussion in 'Native Lenses' started by Hyubie, Oct 14, 2011.

  1. Hyubie

    Hyubie Unique like everyone else

    Oct 15, 2010
    Massachusetts
    Herbert
    Just wondering - am I in the minority as far as aperture settings are concerned? I tend to I leave my lens wide-open more often than not. I figured if I am going to pay the premium for that f/1.7 on the 20mm, I might as well maximize its use.

    Ditto for the 17 mm f/2.8, even my Canon FD 50mm f/1.4 is usually only between f/2 and f/4, several times wide-open, but rarely smaller than f4.

    Probably too because I shoot people mostly, but even then most of the guides/suggestions tend to say use f/4 for portrait.

    (Did I just open a can of worms, Pandora's box, what-have-you's ?? :biggrin: I'm bracing myself.)
     
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  2. RevBob

    RevBob Super Moderator

    Jun 4, 2011
    NorthWestern PA
    Bob
    Most lenses have a "sweet spot", an aperture that gives the best sharpness and contrast. Very, very rarely is that wide open. Usually it is a couple of stops above the widest. The advantage to a fast lens is that you still end up with a wider aperture than you would if you used a slower lens. Two stops above f1.7 is still a lot faster than two stops above f3.5. You can still shoot wide open, but you often sacrifice corner softness and sometimes contrast. I portrait photography the corner softness is rarely a problem.
     
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  3. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    Houston
    Muttley
    I shoot wide open most of the time as well. BUT, in a street or outdoor situation in the daylight, it's probably easier to get "crisper" or "sharper" photos by keeping that aperture down a little bit, particularly for environmental portraits. Plus, at F1.7, on a sunny day, it's easy to get blown highlights even at the lowest or base ISO, unless you have a ND filter on.
     
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  4. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    Houston
    Muttley
    Good point about the "sweet" spot Bob!
     
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  5. Hyubie

    Hyubie Unique like everyone else

    Oct 15, 2010
    Massachusetts
    Herbert
    Good point about not shooting wide-open on a sunny day. I usually go much smaller, of course. :smile:

    As for the sweet spot, yes, I am aware of it, but unless I blow up the image, I really can't discern the diff in sharpness. I guess this tells me I'm willing to sacrifice the sharpness for DOF/speed.
     
  6. I shoot as whatever aperture is appropriate for how I want an image to look, how much I want in focus, etc. M4/3 (and 4/3) have always seemed very good at shooting wide-open and encourage you to do this. Shooting an older legacy lens wide-open shows an area where lens design has improved; most ones I've used have a glow which can look okay in b&w but rarely so in colour. I've long had a habit of shooting no wider than a half-stop off wide-open but I'm not so vigilant of that anymore with m4/3 lenses.
     
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  7. SNTP

    SNTP Mu-43 Regular

    126
    Sep 7, 2011
    Yea i think that because of the way m43 is, and how dof is created, most of the times i have to shoot wide open with my ND filters. This past weekend ago, i was using my ND8 on my 20mm f1.7. Although i normally like to shoot at F2.2 or F4 with my 20mm when i know i want a sharp crisp photo. I still need to play around with my 45 f1.8, but I'm going to assume that the sharpness will be similar to the 20, and that f2.2-f4 will be nice and sweet. The advantage there is that the 45 has a nicer focal length giving you that sweet dof bokeh.
    I think the main thing is that if you want a sharp photo but still want that dof blur, you've got to work on your background choice and make sure that it's nice and far from your subject, esp with the 20.
    But if you took a count of all my shots, i probably have about 80-90% at wide open aperature. The thing that was hard for me to learn was using focal length to create depth instead of wide open aperatures.
     
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  8. mccalltd

    mccalltd New to Mu-43

    6
    Oct 14, 2011
    Wide open when lights or low or for effect

    Hi Hyubie,

    I tend to use wide open only when the lack of light necessitates or I am going for a certain effect. I have the 20mm 1.7 and 45mm 1.8, and take a lot of close portraits of my two-year-old and others. At wide open and close range, focusing right on eyes requires a bit of luck. So you have to consider your distance to the subject and the depth of field you want to use. If I'm near the close range of the lens, I'll definitely stop down to around f4 (light permitting) so that I can get the face in focus with good success. But if I'm further away, then I open up to help keep the background out-of-focus.

    I agree -- you pay for a big aperture so why not use it. But it's more complicated than that, especially for portraits. If you have too-shallow-dof problems when you review your pictures, or if you want to actually have a focused face for your subject, rather than only a hair on their chin or cheek instead of their eyes, you should memorize common focal length/distance to subject/f-stop values that yield desirable DOF. This site has a handy calculator: Online Depth of Field Calculator.

    Cheers
     
  9. avidone

    avidone Mu-43 Top Veteran

    520
    Jun 24, 2011
    Rome, Italy
    I shoot wide open a lot, partly for available light work, partly for shallow DOF, partly because I keep getting legacy glass that needs checking out at it's fastest extreme. I am aware of the sweet spot and am trying to be more disciplined about that, but, honestly, razor-sharp is not always at the top of my list when composing or grabbing an image. And with legacy lenses especially, I don't mind a bit of "imperfection" because I think it contributes to the character of the lens.

    In other words, I am trying (not always successfully) to make good photos much more than I am trying to pixel peep.