E-P1 AF Selection

Discussion in 'Olympus Cameras' started by mitchins, Nov 27, 2010.

  1. mitchins

    mitchins New to Mu-43

    8
    Nov 24, 2010
    Sydney, Australia
    Hi all,
    I'm relatively new to the PEN and this forum, so it might have already been covered somewhere. Out of irritance of the camera choosing whatever it sees fit for focus/metering, I set my E-P1 to centre spot focus, however this limits my ability to compose anything other than holiday snaps easily.

    On my Alpha 850 one of my favourite things is using the joystick to set the focus point for AF instantly and easily, I can't see anything easily on the PEN, does anyone know anything about this?

    Thanks guys
     
    • Like Like x 1
  2. Vivalo

    Vivalo Olympus Loser

    941
    Nov 16, 2010
    Finland
    You can change your focus point from the super control menu (or whatever that is called) when you hit the ok-button and there about in the middle of the selection pattern you have the field where you can set the focus area. From there you can choose any of the focus points or the whole area, in which case the camera will choose the "right" point for you.

    I personally keep the focus point nearly always in the middle and then focus first to the subject I want to be sharp and then (while keeping the shutter button half-pressed) frame/compose the shot. This way I can be sure where the focus will be and it is a lot faster than anykind of way to change the focus point.

    -Ville
     
    • Like Like x 1
  3. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    X2
     
  4. sparkin

    sparkin Mu-43 Regular

    173
    Nov 18, 2010
    Lexington, KY
    X3! Doesn't everyone do this ? :smile:
     
  5. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    Apparently not. Perhaps it breaks down to people who used compacts (where this practice is really necessary due to slow AF) and those who came from SLRs?
     
  6. Vivalo

    Vivalo Olympus Loser

    941
    Nov 16, 2010
    Finland
    I had Oly E-520 before and it only had 3 focus points very close to each other, so usually I didn't bother to change it from the center. I really don't see the point why to change it (focus point) in dynamic shooting situation unless you are taking a long burst while panning or something like that, which isn't E-P1's cup of tea anyway.
     
  7. x4!

    Don't some of the latest Nikons have something like 51 AF points? About 50 too many IMO.
     
  8. mitchins

    mitchins New to Mu-43

    8
    Nov 24, 2010
    Sydney, Australia
    Oh so you focus on the centre and the move to place the focused subject where you want?
    I wouldn't think of doing this because when you move or rotate the camera the focus point might change, although this is probably less of an issue than it is at 50mm/1.4 on FF (larger DOF on m4/3).
    Thanks guys I'll try this.
     
  9. I've never had a focussing problem using the centre point focus and reframe method (albeit using APS-C and 4/3 sensor cameras). The centre AF point is generally the most sensitive so should be the most accurate. Changing the AF point prior to shooting would seem to me to be fairly time consuming process.
     
  10. mitchins

    mitchins New to Mu-43

    8
    Nov 24, 2010
    Sydney, Australia
    Very interesting ... thanks.
    Does it actually matter for accuracy where you focus using Contrast Detect AF?
     
  11. I'd assume that contrast detect AF works consistently across the entire frame.
     
  12. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    If AF points become the next MP War, we should say that our CDAF cameras have 12 million AF points LOL

    The key is you have to hold the shutter button at the half press while recomposing, that locks the AF and exposure where you set it. Note that the other option when taking photos of people is to enable the face detection.
     
  13. 3drives

    3drives New to Mu-43

    6
    Nov 22, 2010
    I need help here. In a shot where there is no subject or multiple subjects (I want sharp focus on everything) I am chosing the whole area to focus. But, like you said the camera is choosing a single focus box in one place. When the pic is taken, rest of the areas in the pic are out of focus. How to avoid that?

    How to get equal focus throughout the picture?
     
  14. squeegee

    squeegee Mu-43 Veteran

    403
    Jan 26, 2010
    I think what you're mixing up 2 different things. The focus point is only where the camera "attempts" to focus, it does not mean everything there is in focus. So as an example if you select the whole picture, it doesn't mean everything in the picture is in focus, similarly even if you select the centre box, it doesn't mean everything in the box is in focus, it means "something" in the box is in focus.

    If you want everything in focus, I think you're going to need to work with the depth of field.

    Online Depth of Field Calculator

    is a link to a calculator. Put in your lens and distance to subject, then look at the near and far focus.

    It's my understanding that to get "more" items in focus, you can basically use a shorter lens, a larger F stop, or move further away from all the items in the picture....

    The realistic option for you is to probably increase the F number you're using.
     
  15. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    3drives - Yes, as mentioned above, the answer is depth of field. If you are moving up from a compact camera, this is probably a new concept because their small sensors give. A large depth of field all the time. With the larger sensor in m43 cameras, you have control over that important aspect of the photo through the aperture control.

    Going to a small aperture (large f/ stop number) is like squinting your eyes and has more of the field of view in focus. This is called large depth of field. The downside, is that the lens let's in less light and so the shutter speed has to be slower (potentially causing blur) or the ISO has to be higher (potentially causing noise). If you go to very small apertures (f/ stops > 11) resolution may be limited by diffraction.

    Setting the aperture "wide open" (small f/ stop number) will give you a shallow depth of field, allowing you to isolate your subject by making the background out of focus. Of course, if the subject is deeper than the DOF, parts of it wil be out of focus, also.

    Lastly, play around with the calculator linked above. You will see that the farther away the subject is, the deeper the depth of field. At macro distances (a few inches), the depth of field will be much less than an inch making it hard to keep any subject all in focus.