Which F stop?

Discussion in 'Photography Beginners' Forum' started by Kofman13, Jan 31, 2010.

  1. Kofman13

    Kofman13 TPF Noob!

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    I'm using an OM 50mm 1.8. Usually I'm on f 1.8 because I do alot of bokeh or close up portraits with bokeh. But if I'm doing some objects or a small scene with nothing behind far away, subject mayb 3-5 feet away. What's a good aperture in your opinions?
     
  2. Alphaem

    Alphaem TPF Noob!

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    If your not trying to create a bokeh effect, I would assume your looking for as sharp an image as possible. So go for the highest f-stop that the lighting conditions will allow f-16 or f-22.
     
  3. dxqcanada

    dxqcanada Been spending a lot of time on here!

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    Look at the lens ... there are Depth of Field aperture marks on the first ring.

    It will show you the range of focus. I think it should start at about f/4.
     
  4. flyin-lowe

    flyin-lowe TPF Noob!

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    I just finished Understanding Exposure and I would recommend it to anyone that is learning photography. The short answer to this question would be to use 1.4-4.0 for good bokeh and to control depth of field. If your subject and the background are close to the same distance ( a man against a wall, a shell laying on the sand etc.) 8.0-11.00, and when you want objects at different distances in focus (shooting a scene with a swing, then a house, then mountains in the background) 16 or higher. These are just quick references and need to be adjusted depending on light and other conditions.
    Pick up the book, its a must.
     
  5. Josh66

    Josh66 Been spending a lot of time on here!

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    Stopping down that much will cause you to loose sharpness due to diffraction.

    f/8-f/11 is usually the sharpest. Though, some lenses are pretty damn sharp at larger apertures - even wide open.

    Sometimes you need the extra DOF that f/22 gives you though, and the little bit of lost sharpness is less important.
     
  6. Derrel

    Derrel Mr. Rain Cloud

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    Using an f/1.8 50mm lens wide-open, you're almost asking for focusing difficulties, as well as inherently shallow depth of field at closer distances, especially on a small 4/3 sensor; on that sensor, a 50 is the 35mm FF equivalent of a 100mm lens. Shooting wide-open gives you almost no margin for error,and the lens will be art its worst performance. I would try f/4 to f/5.6 under the conditions you mention. You will get some more depth of field, plus the lens will be closer to its "sweet spot", which on fast 50's is often somewhere around f/4 to f/5.6.
     
  7. vd853

    vd853 TPF Noob!

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    You need to find out what F your lens is sharpest at. Example, my 50mm 1.4 is sharpest around 2.8 to 8. I only take it down to 1.4 to 1.8 when it is too dark, and I almost never go up to 22. When taking portraits, I usually have enough light so 2.8 to 5.6 is good enough in most cases. My pictures usually come out sharpest when I use 2.8 to 5.6 with fast shutter speed and low ISO.
     
  8. Bitter Jeweler

    Bitter Jeweler Been spending a lot of time on here!

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    You should switch to Canon. They have better F-stops.
     
  9. Vautrin

    Vautrin No longer a newbie, moving up!

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    look for this info on your lens manufacturers web site or on camera reviews...
     

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