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How to pre focus with oly 17mm

Discussion in 'Native Lenses' started by Idreamphoto, Apr 3, 2013.

  1. Idreamphoto

    Idreamphoto Mu-43 Regular

    87
    Sep 1, 2012
    Hi,

    See the photo of my 17mm below, i am learning how to pre focus. But on the strret most of my sujet i want to focus on are located at 4 m distance.
    The graduation is not precise, how can i get close to the 4m distance?
    Thanks

    Camera Roll-595 | Flickr - Photo Sharing!

    [​IMG]
     
  2. WT21

    WT21 Mu-43 Hall of Famer

    Feb 19, 2010
    Boston
    stop down, then the area in between the two markings will be in focus. e.g. stop down to f/11, and all the range set between the two 11 marks are in focus.

    You can't really use a focus scale very effectively for shooting at wide apertures.
     
  3. Idreamphoto

    Idreamphoto Mu-43 Regular

    87
    Sep 1, 2012
    Thansk, i know how the focus scale work.
    I am juste very surprized that there is such a small distance between 3m and infinity...
     
  4. mh2000

    mh2000 Mu-43 Veteran

    254
    Jul 3, 2010
    For f11 the hyperfocal distance is 4m (based on standard assumptions). Set the far mark for f11 and the focus should be set pretty close to 4m. As has been noted elsewhere, Oly has chosen to be very conservative in their CoC -- probably for pixel peeping complainers!
     
  5. JoeV

    JoeV Mu-43 Regular

    85
    Aug 22, 2012
    Albuquerque, New Mexico, USA
    Joe Van Cleave
    Just to clarify, so what are the "standard assumptions?"

    I ask this not to be argumentative (honestly), but because in my some 35 years of photography, I've found DOF scales to be only marginally helpful, and in large part depends upon what you're going to do with the files - especially how much enlargement they will suffer in post-production. What's "acceptably sharp" for an 800 pixel-wide Internet JPEG might not be acceptable for printing to 18"x24", for instance.

    More to the point of the OP's question, I don't think he was as interested in DOF as in presetting focus to a 4 meter distance. If I were using his gear, I'd simply pace off a distance of about 4m to some easy-to-focus-upon object, and set the focus manually to that distance.

    ~Joe
     
  6. RobWatson

    RobWatson Mu-43 Hall of Famer

    I certainly don't have 35 years photography experience (well, I have been taking crappy pictures for about that long) but that is how I read the OP and that is how I would do it, too.

    I would also suggest to adjust the camera settings so the lens does not reset on power cycle and turn off AF or put the AF mode such that AF happens with AEL/AFL button or something like that so as to prevent focus changing between shots.

    A park bench or a light pole (lots of empty space in the background) or something like that at the 4m distance and set the focus on the object and away you go. At least those would be my 'easy-to-focus' target choices. I'd even let AF do it (MF with natives is tough for me).
     
  7. sokar

    sokar Mu-43 Veteran

    392
    Nov 30, 2011
    Idreamphoto,

    I use the older 17mm F2.8 with no focussing scale for street photography with my EP1. I set SAF to mode 3 which enables focussing the lens via the AFL/AEL button. I have the lens reset switched off, and therefore the camera can be turned off and on and remains focussed. Sleep mode for the camera set at 5 minutes and LCD on / off via the function button.

    I use the DOF Master phone app to set the correct hyperfocal settings at different apertures. I mostly use F/8 and set the focus on 8ft. This provides a hyperfocal distance of 1.5m - infinity @ F/8.
     
  8. Idreamphoto

    Idreamphoto Mu-43 Regular

    87
    Sep 1, 2012
    Thanks for your ideas.
    - camera does not reset focus when switching on/off, i have it
    - using another button to AF, and avoid AF when pushing shutter button is unecessary, because the way that this lens works is that you can mecanically put the ring on the lens, you then switch to full MF mode, in the same time the dof scale appears, you can see it only in MF mode
    - so the way that this lens founctions, you cannot really "cheat" by facilitating focus on something using camera AF then leave it then for the next shoots.
    - i see the only way is to use this lens in manual mode and manually pre focus on something at the 4m distance (i wonder how i can find something at 4 m distance when running n the streets without any ruler)
     
  9. Mogul

    Mogul Mu-43 Regular

    193
    Nov 9, 2012
    Set your aperture at f/8 and manual focus to 3 meters. Everything from 1.3m to ∞ will be in focus.
     
  10. Idreamphoto

    Idreamphoto Mu-43 Regular

    87
    Sep 1, 2012
    Thanks i really appreciate the advice. It is clear that closing aperture helps to get dof. But sometime ( the most of the time) I dont shot f8 or f11, but rather at f5.6 or f4.
     
  11. sokar

    sokar Mu-43 Veteran

    392
    Nov 30, 2011
    From the the DOF Master phone app

    Format CoC: 0.015mm (M43 sensor)
    Lens: 17mm

    Hyperfocal Distances

    F/4
    Focus @ 4.83m = near limit 2.42m / far limit 6345m

    F/5.6
    Focus @ 3.42m = near limit 1.71m / far limit 4020m

    F/8
    Focus @ 2.43m = near limit 1.21m / far limit infinity
     
  12. Cruzan80

    Cruzan80 Mu-43 All-Pro

    Aug 23, 2012
    Denver, Co
    Sean Rastsmith
    Easiest way to find something 4m away is to measure your standard footsteps. Take a about 5 or 10 paces (10-20 steps), measure and divide for an average. My stride (1 step) is close enough to 1m for me to measure fairly accurately. Once you know that, start at a pole, then pace off the distance, focus and you are set.
     
  13. Idreamphoto

    Idreamphoto Mu-43 Regular

    87
    Sep 1, 2012
    Thanks. Very good idea indeed. So simple that I didnt think about it. Btw, i just made a couple of tests. And I confirm that the dof scale on the oly 17mm 1.8 is not accurate at all. The dof scale on the lens seems to indicate a value higher than the real distance.
     
  14. Mogul

    Mogul Mu-43 Regular

    193
    Nov 9, 2012
    At 5.6, focused at 3m, everything from 1.6m to 24.2m will be in focus. Focused at 3.5m, everything from 1.73m to ∞ will be in focus.