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GX7 inaccurate exposure preview and electronic shutter behaving differently in A and M mode (pics)

Discussion in 'Panasonic Cameras' started by boomer, Dec 26, 2013.

  1. boomer

    boomer New to Mu-43

    8
    Nov 9, 2013
    Hi

    I have noticed that exposure preview in EVF is not accurate unless camera is in manual mode. In aperture priority pictures comes out darker or lighter than seen in evf or lcd. It's easy to notice when one second image preview after each shot is set on camera (and it's most obvious when shot in darker places). In manual mode it's not present at all and exposure is previewed accurately.

    What's even weirder banding caused because of interaction of the electronic shutter with the fluorescent lights is different when shot in manual mode vs aperture priority mode
    for example:
    50hz fluorescent light doesn't cause banding when shot with electronic shutter at 1/25 1/50 or 1/100 (banding is even accurately previewable on lcd or evf but again only in M manual mode)

    both pics shot at 1/100s iso1600 and in aperture priority banding is present (left) manual mode banding is not present (right)
    ScreenHunter_36 Dec. 26 10.43.

    same here 1/50s iso 800
    ScreenHunter_36 Dec. 26 10.42.

    I have shot many more pics yesterday at different shuter speeds and iso settings with same results.
    I think those two observations are connected to each other and there is something weird and unequal in aperture priority mode.
    None of this is present on my second camera EM1 (I know there is no electronic shutter but exposure previews are equally accurate in every mode)

    I know that many may not care about electronic shutter at all but I'm sure everyone would like to have accurate exposure preview in evf not only while in manual mode so I guess it's rather important issue.
     
  2. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    The LCD image is not an "accurate" representation as the image is adjusted to assist in seeing an acceptable photo in very right or dark scenes. Regarding the banding, it is normal to see the banding when the electronic shutter is used under a fluorescent light. The banding can be reduced, but not necessarily eliminated when the shutter speed is a multiple of the local AC line voltage frequency. In the US line freq is 60 he, so shutter speed of 1\60, 1/120 ....could reduce it, but no guarantee.
     
  3. Cruzan80

    Cruzan80 Mu-43 All-Pro

    Aug 23, 2012
    Denver, Co
    Sean Rastsmith
    If you set one of your buttons to Preview, the second setting "shutter speed effect off" should show you a corrected display. The first one shows DoF, the second exposure.
     
    • Like Like x 1
  4. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Boomer, You have also posted this exact post in dpreview forums. Perhaps we should just follow the thread there?

    Anyway, my GX7 is not like yours. In P, A, and S mode, the back screen preview looks exactly the same as the playback image. There is no issue.

    The problem you report seems to be either operator error or a faulty unit. Maybe return your GX7 for attention, or at least take it to the store for discussion.
     
  5. boomer

    boomer New to Mu-43

    8
    Nov 9, 2013
    Yes I did post it there since I wasn't sure which forum choose at the time
    I got more answers there: http://www.dpreview.com/forums/thread/3597377#forum-post-52786983

    Cruzan80: "shutter speed effect off" for a moment shows proper true exposure preview but also locks exposure preview. this function is for something else and cannot be used for general shooting.( also switches off automaticly if anything else is pressed). anyway who want's to keep pressing that button to get preview which should be there in the first place.
    In manual mode everything works as it should. on Olympus omd exp.preview in all modes works equally accurate
     
  6. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    Hi, I'm not sure you read my post properly. For me, preview looks exactly the same as the recorded image in P, A, and S, modes. i.e. the effects of exposure correction are correctly displayed on the screen. The problem you described does not exist.

    M mode is different. In M mode, preview is 'constant brightness' when 'Custom/Constant Preview' is OFF, but turn it ON and the preview will match the recorded image in M too. It only affects the display in M mode.

    Add to that the explanation given by 'Helen' on dpreview for the banding, that A mode might display 1/100 but actually be steplessly slightly different, and your concerns that the camera is doing things wrong seem to be baseless.
     
    • Like Like x 1
  7. boomer

    boomer New to Mu-43

    8
    Nov 9, 2013
    darker the place = stronger the exposure preview shift (brighter). try that in darker room with weak light source and aim at something in the shadow. It's the easiest way to reproduce that but it occurs in different situations as well.
    I could make a youtube video but I would rather not waste time for that since it's very easy to reproduce it once you know what to look for.
    problem doesn't exist in manual mode with 'Custom/Constant Preview' ON. - darker places aren't boosted and are presented accurately.
     
  8. T N Args

    T N Args Agent Photocateur

    Dec 3, 2013
    Adelaide, Australia
    call me Arg
    See my reply on dpreview. You seem to be describing quite extreme and irregular lighting conditions. Maybe post (preferably on one site only; I can't stand double parallel thread maintenance) the actual exposure values where your mismatch does and doesn't occur in A mode.