Any idea whats fogging this exposure?

Discussion in 'Olympus Cameras' started by walter_j, Jan 27, 2014.

  1. walter_j

    walter_j Mu-43 Veteran

    364
    Sep 10, 2013
    Hagwilget, B.C., Canada
    Walter
    I took this pic with OM-D E-M5 with a 12mm F2, at F2, 25 seconds, ISO 4000. Temperature is about -3 Celcius. Is lens fogging up or is it a sensor problem? There didn't appear to be any fog on lens when I brought it inside. The problem got worse the longer I stayed outside. Initially it was just noticeable at top left edge, and gradually moved down. Any ideas? (First time taking long exposures at night in cool weather). I took pics all day outside with same and other lens without problems. Subsequent pictures inside didn't have any problem.
     

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  2. Pili

    Pili Mu-43 Veteran

    224
    Jul 16, 2012
    Boulder, CO
    Alex
    Weird, does it show up in shorter exposures in the same conditions or just in the long exposure? Almost looks like there is some moisture in the lens that is freezing...maybe try throwing the lens in a bag of rice for 24 hours for the sake of curiosity?
     
  3. mister_roboto

    mister_roboto Mu-43 Top Veteran

    637
    Jun 14, 2011
    Seattle, WA, USA
    Dennis
    It looks like clouds in the sky. Hard to see at night, but the camera sees slightly better than you do- with long exposures :wink:
     
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  4. walter_j

    walter_j Mu-43 Veteran

    364
    Sep 10, 2013
    Hagwilget, B.C., Canada
    Walter
    Might be condensation in lens. Seemed to get worse the longer I was outside. Another shot an hour later worked perfectly, but I didn't stay outside too long. If it is condensation, would I just have to leave it outside to acclimatize? Or do I need to heat the camera?
     
  5. wjiang

    wjiang Mu-43 Hall of Famer

    Condensation is usually from the following:
    1) Cold to hot and humid - ambient humidity condenses on cold lens outer surface.
    2) Hot and humid to cold - outside of lens rapidly cooled, humidity inside the lens condenses on lens inner surface.

    Condensation should get better overtime as things equalise, not worse. As it's getting worse, starting from the top, and it looks like the lens is at least pointed somewhat upwards, I suspect that it's dew/frost settling on the lens. If that is the case, try a lens hood or some other cover so the moisture settles on the that instead.
     
  6. walter_j

    walter_j Mu-43 Veteran

    364
    Sep 10, 2013
    Hagwilget, B.C., Canada
    Walter
    Thanks. I'll have to buy Oly's hood now I guess. They're prices are crazy
     
  7. jloden

    jloden Mu-43 Hall of Famer

    May 15, 2012
    Hunterdon County, NJ
    Jay
    I'm with Dennis on this one, that looks to me like simply cloud cover moving overhead in this particular case.

    I've had condensation issues going from cold to hot environments such as winter outdoors to indoors, or indoor A/C to hot summer day, but never had any issues while still out in the cold. -3º C just isn't that cold, so I don't think it's frosting over or condensing. I did some astrophotography at the Haleakala summit this past summer and I assure you, it was colder than -3º C :biggrin:

    In that case I didn't run into any condensation issues, at least until I went inside. Ended up wrapping my cameras in my coat to slow the temperature shift once it was time to get in the car and warm back up.
     
  8. dwig

    dwig Mu-43 Top Veteran

    623
    Jun 26, 2010
    Key West FL
    +1

    Take note of the single star shining through the cloud and the fact that the clouds are an appropriate gray for clouds dimly lit from below.

    The naked eye will not see near as many stars as a long camera exposure and will thus often miss that some of the star field is blocked by clouds. The clouds only become noticable when the star field is visible enough to make the blanked out areas visible and/or when the clouds are reflecting bright city light.
     
  9. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
    I agree. It's a cloud.
     
  10. DoofClenas

    DoofClenas Who needs a Mirror!

    946
    Nov 9, 2012
    Traverse City, MI
    Clint
    cloud...
     
  11. wjiang

    wjiang Mu-43 Hall of Famer

    I would ascertain whether it is dew/frost before committing to that. What happens if you try another lens with a different FoV? If it is cloud it should come out appropriately different based on the FoV change, but in the same place relative to the rest of the scene. Also if you want a good the JJC ones are great alternatives to the Olympus ones.