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pink blob

Discussion in 'Panasonic Cameras' started by thriva, Sep 24, 2012.

  1. thriva

    thriva New to Mu-43

    2
    Sep 24, 2012
    Blob is too harsh a word but...

    A few months ago I bought a G2 for my daughter and I to share, only with one thing and another we found we couldn't share it - she likes the kit lens and I prefer my nikon primes, so we constantly having to change settings and so on.

    Anyway, finally I decide to buy another G2 body from eBay and take it out for the first time on a lovely sunny afternoon and take some shots. On my return I find that several (12 out of the 50 taken) have a slightly pink area right in the center of the frame. Examples here

    What do you think this is?
    Is sunlight getting in and so a problem with the adapter maybe? or is there a problem with the camera and do I have grounds to return it?

    Thanks in advance
     
  2. addieleman

    addieleman Mu-43 All-Pro

    Aug 5, 2010
    The Netherlands
    Ad
    It could indeed be a reflection due to the adapter, in that case you shouldn't see it when using native lenses. At all. My first Nikon F adapter caused terrible flare, my Novoflex NIK-MFT doesn't and all cheapo Minolta MD adapters are trouble-free as well.

    Have you inspected the sensor? Maybe it's dirty in the middle. Or a long shot: maybe it has been damaged by lying in the sun for a long time. If it shows with native lenses and you can't get rid of it by cleaning the sensor, I think I'd return it to be on the safe side. Another G2 shouldn't be too hard to get.
     
  3. RevBob

    RevBob Super Moderator

    Jun 4, 2011
    NorthWestern PA
    Bob
    I had to look for it, but definitely see it in most of the photos. Is it happening with one lens in particular, or with different lenses? Does it only happen when using an adapter, or does it do it with the kit lens? It could be a particular lens or the adapter, hard to be sure without more info.
     
  4. RobWatson

    RobWatson Mu-43 Hall of Famer

    Use a lens hood?

    I've had several adapters that had very shiny inside surfaces which resulted in similar problems. A bit of flocking paper (or flat black paint) clears things up nicely when applied to the offending surfaces of the adapter.
     
  5. uci2ci

    uci2ci Mu-43 All-Pro

    Jun 22, 2012
    Los Angeles, CA
    Sam
    • Like Like x 1
  6. thriva

    thriva New to Mu-43

    2
    Sep 24, 2012
    Thanks everyone for your replies. I will certainly check out the kit lens when the weather is better than it has been today!!

    Yes, I was using a hood all day and a ND filter for the water shots.

    This is my first decent digital camera and I haven't yet had the nerve to check out the sensor, I know it can be automatically cleaned but that only works under some circumstances.

    You know what tho'... I think uci2ci has hit the nail on the head... the lens that I was using was a Nikkor 50mm f1.8 and the aperture was probably f16 or f22 for the water shots. Apparently this is a common problem with older nikon lenses with this focal length at small apertures due to the more reflective coatings used on lenses designed for film. The examples shown on the thread look very similar to mine. This is hopeful because it looks as though I will still be able to use this lens, just at wider apertures. I feel that treating the inside of the adapter is also worth trying - I can't help feeling that the less light bouncing about in there the better.

    Thanks again everyone!
     
    • Like Like x 1
  7. Wasabi Bob

    Wasabi Bob Mu-43 Top Veteran

    Here's some things to try.

    If we don't know what's causing it, try to figure out what's not related.

    1. Does it occur indoors, out of bright light?
    2. Does it occur will all lens, or just adapted?
    3. Indoors, trying getting a bright light and shine it at the lens from several angles just as the sun would do under normal use.
    4. Remove the lens (enable the shoot w/o lens option) and place the camera in front of a piece of white paper. Do you see any blemishes in the area where the spot occurs?
    5. Take a test shot in which you see the blemish. In the same position, wrap a piece of dark cloth around the lens and see if it disappears. If it does, it's obviously some sort of a light leak.
     
  8. Sanpaku

    Sanpaku Mu-43 Regular

    79
    Jul 24, 2012
    I concur with uci2ci, it looks like sensor reflection. I suggest a comparison with the examples presented at The Digital Sensor Reflection Effect.

    The difference in color (pink/magenta vs yellow at the link) is an artifact of the various coatings on the rear element and sensor.
     
  9. RobWatson

    RobWatson Mu-43 Hall of Famer

    "sensor reflection" ... not sure I buy this one. Certainly it can happen but I'd prefer to eliminate the obvious sources before pinning it on this effect.

    For example with adapted lenes the image circle is generally huge compared to the m43 sensor and all that light bouncing around is going to go some where. Judicious placement of a field stop will help greatly - trial and error for the size is not that hard and the choices fro placement are fairly restricted.

    Check throughput (signal level / exposure) to ensure that the field stop (supposed to block unwanted light) is not becoming an aperture stop (wanted light) - if exposure levels drop the placement or size of the field stop is not correct. One may notice significant vignetting before noticing exposure levels dropping - this is another symptom of too small of a field stop.

    Please recall that camera/sensor designers make the sensor to collect light so any reflections from the sensor are light lost - this is assiduously avioded at great pains by designers.