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Olympus 9-18 AF-C issue with GX-7

Discussion in 'Native Lenses' started by mannukiddo, Apr 29, 2015.

  1. mannukiddo

    mannukiddo Mu-43 Veteran

    217
    Jul 28, 2013
    India
    I recently took delivery of a Olympus 9-18 for use with filters when I want to go wider than 14 2.5 which is the widest lens I have currently that accepts filters. I have a 7-14 for UWA needs but got the Oly for its ability to take filters

    Now I am facing a peculiar problem when I use this lens on my GX-7 in AF-C. There is a jumping of focus and I can see that in both the Live View / EVF, the scene moves forward and back all the while when the shutter button is half pressed for acquiring focus. This issue is not seen on my GX-1. But when I use AF-S on GX-7 this jumping of the view ceases completely in both the EVF and LV. Is this a known problem with this lens? I only intend to use this lens for landscapes on a tripod with no real need of AF-C. So far I am liking this lens except for this weird behavior in AF-C on my GX-7.

    Any insights on this will be highly appreciated.
     
    Last edited: Apr 30, 2015
  2. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    It's not an issue with the lens, its the fact that you're using AFC (which is why it stops doing this when you switch to AFS). FWIW, my GH3 & GH4 both do this when I have them set to AFC mode. You'll see that if you take a picture, it should be in focus, despite what you're seeing in Live View (the jumping back and forth is because it is continuously auto-focusing.)

    Like you said, you're not even going to be using AFC with this lens since it'll be for landscapes, so I wouldn't worry about it.
     
    • Informative Informative x 1
  3. mannukiddo

    mannukiddo Mu-43 Veteran

    217
    Jul 28, 2013
    India

    Thanks that is helpful. I was only concerned as none of my other lenses do this including my only other Olympus lens, the 45 1.8 and most importantly, this does not happen on my GX-1.
     
    Last edited: Apr 29, 2015
  4. ex machina

    ex machina Mu-43 Top Veteran

    805
    Jan 3, 2014
    Northern Virgnia
    It does sound odd that the other lenses/camera combination don't do that, though I think if the lighting conditions aren't right, AFC falls back to AFS? I've never used AFC on my GX7/o9-18, but I also have a GX1, so if I have enough brain cells left by the end of the day to remember, I'll take a look and see if I can replicate the same behavior when I get home.
     
  5. Duncan

    Duncan Mu-43 Regular

    110
    Oct 31, 2013
    I see the same jumping image in AFC with my GX-7 and Oly 9-18mm lens. When I put the Oly 45mm lens on the camera, however, I can hear a slight stuttering or clicking noise (put your ear to the camera in a quiet room), and I believe I can see some very very subtle image jittering. Then I tried my Panny 14-140mm (version 1) lens. At full telephoto I could not see any jittering at all, but at the 14mm end, some jittering was clearly visible, and I could hear a very faint clicking noise. So it seems like it is more prevalent at shorter focal lengths and is not limited to Oly lenses. Oddly, when I tried my Panny 20mm lens I could not engage AFC. Even though I had AFC set in the custom menu, the display always said AFS. When I tried to change it using the Q. Menu, no AF choices were available; only AFS was possible. None of my other lenses do that. Does anyone have any ideas why this is happening? My 20mm is version 2.
     
  6. tkbslc

    tkbslc Mu-43 Hall of Famer

    AF-C is not supported with the 20mm lens, per Panasonic compatibility guides. My guess is that the AF design of the lens can't handle it anyway, so Panasonic just disabled it.

    http://av.jpn.support.panasonic.com/support/global/cs/dsc/connect/gx7.html

    It is also not supported on the Olympus 17mm f2.8 and the older Olympus kit lenses.
     
    • Informative Informative x 1
  7. ex machina

    ex machina Mu-43 Top Veteran

    805
    Jan 3, 2014
    Northern Virgnia
    Ok, so I witnessed the jitter on my GX7/o9-18, moved the lens to my GX1, and at first it seemed there was no jitter -- the camera reached focus and stayed put. However, once I pointed the GX1 elsewhere, forcing it to refocus, when I returned to the original spot the jitter was present.

    Thanks for giving me a reason to break out my GX1, the GX7 gets all the action so I kinda forget what a nice little camera it is.
     
  8. Duncan

    Duncan Mu-43 Regular

    110
    Oct 31, 2013
    Thanks, I never realized that. Shows you how often I use AFC.
     
  9. dornblaser

    dornblaser Mu-43 Hall of Famer

    Aug 13, 2012
    Chicago-area
    David Dornblaser
    I kind of missing reading about and seeing pics from the GX1. Popular camera. If I am reading this right, some of the older lenses work best with older bodies and with newer bodies? Is this strictly a function of AF?
     
  10. mannukiddo

    mannukiddo Mu-43 Veteran

    217
    Jul 28, 2013
    India
    So it is normal for this lens to jitter on a GX-7. I am surprised that I could not find much info on this anywhere, probably because no one really thinks its a big issue. Even the 20 1.7 behavior was completely new to me.
     
  11. ex machina

    ex machina Mu-43 Top Veteran

    805
    Jan 3, 2014
    Northern Virgnia
    As I experienced this difference between the GX7 and GX1's behavior, I was imagining that the GX1's designers initially decided that deferring focus "Seeking" until the subject matter changed in AF-C was a useful feature, then later changed their minds with the GX7. Of course, it could have been a bug in the GX1's firmware. ;)

    Would be interesting to see how other, newer Panny cameras act.