Decentered camera! (E-M5 II with ultra-wide lenses)

Discussion in 'Olympus Cameras' started by Egregius V, Jul 26, 2016.

  1. Egregius V

    Egregius V Mu-43 Regular

    127
    Jun 14, 2015
    Massachusetts, USA
    Rev. Gregory Vozzo
    Hi, everyone. I've had some recent experience with decentering in lenses: specifically, I tested three Oly. 75-300 II lenses and had one with perfect symmetry, one obviously decentered across the frame, and one with a bad corner in the 100-150mm range. Now I have an Oly. 7-14 PRO and have been comparing it with my 9-18 and Pan. 12-32. The good news is that all three lenses take outstanding photos. However, with all three, I am seeing an extra amount of blur along the right side of the frame (especially in the corners) in scenes where there is already some edge/corner softness due to field curvature and depth. Stopping down (or changing the focus point to favor the foreground scenery toward the edges) naturally reduces or eliminates the asymmetry.

    So far, I have not seen these signs of decentering with my GX85, so it seems to be a problem with the E-M5 II's lens mount or sensor. The camera is out of warranty, so I'm in no hurry to send it in for repair. Just wondering - might there be a way to deal with this problem myself or at least be more certain about the cause? For instance, I notice that the lens mount has been stained black over time: might simply cleaning it (with what?) resolve this? Thanks for sharing your thoughts.
     
  2. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Isopropyl aka rubbing alcohol is a safe and effective cleaner... use with q-tips or cotton balls or a non abrasive cloth.
     
    • Informative Informative x 1
  3. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    I doubt dirt on the mount is the issue, but easy to try it anyhow.

    I sometimes see odd focus shift across the frame on my E-M1 and I'm sort of coming to the conclusion that it's the IBIS. For me it's most obvious with longer lenses and when I'm holding the camera vertical. It's not consistent which leads me to believe it's IBIS.
     
    • Informative Informative x 1
  4. Egregius V

    Egregius V Mu-43 Regular

    127
    Jun 14, 2015
    Massachusetts, USA
    Rev. Gregory Vozzo
    Thanks, Paul and Barry, for your suggestions. Very helpful. I'll try to clean my camera up later tonight. It's only lightly soiled, but the stuff is all over the rim of the mount.

    For now, I wiped the lens mount a bit with my finger, then found another place to do some tests and ran a slew of them with both cameras. IBIS off on the E-M5 II. This time, to my relief, the E-M5 II behaved quite a bit better. I saw a little bit of variation in corner sharpness with both cameras, which seems normal. Still, between the two cameras, the results were consistent enough that I have to believe there's slight asymmetry in all three of my lenses. The field curvature of the 7-14 and 9-18 make it show up more with those two. In light of that and the fact that only the extreme corners are affected, I am inclined to think there's actually nothing to fret about here and will move on. I know that I will rarely notice such imprecision in practice. It's just a bit disappointing to see any asymmetry in my two most expensive lenses - whatever the cause.

    Turning IBIS off in the E-M5 II didn't hurt! I can't be absolutely certain it contributed to my present situation (I'm guessing it did); however, I think I came across the same issue as you described, Paul, in some of my vacation shots with the 14-150 II - one at ~65mm and one at 150mm. The field of focus became more shallow than it should be and moved significantly off-center - not just to the right, but seemingly turned at a slight angle. The problem could have been caused by sudden movements (as I was riding in an off-road vehicle at the time) - implicating the IBIS.

    A little epilogue - perhaps a further reminder of the need to embrace imperfection and just enjoy my gear: I dropped the front lens cap of the 7-14 PRO this afternoon. It sure bounced a lot on the gritty driveway. It got a little uglier, too. Works just the same, though! :whistling:
     
    Last edited: Jul 27, 2016