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Thread: Purple/magenta ghosting with GH1, but not GF1?

  1. #1
    capital
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    Purple/magenta ghosting with GH1, but not GF1?

    It sounds strange, and always thought it was just something about my Voigtlander lenses than was producing these really pronounces purple flares/ghost on my GH1.

    I just got a GF1 w/20mm lens however, and it doesn't occur at all. not with any of my lenses.

    I tried the 20 on the GH1 and big purple ghosting.
    Now I actually think it looks really cool, but this doesn't make sense?


    I cropped out a portion of an image to show it...

  2. #2
    Member kwalsh's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Well, so a theory is that with these 35mm film lenses they project a huge image circle compared to the sensor and thus there is a lot of extra light splashing around inside the camera. It is quite possible that the area surrounding the sensor is different in the two cameras and one of them is more likely to catch a reflection from some place. Of course, usually everything around the sensor is matte black to absorb. If you want to test if this is the problem first tripod mount the GH1 so that the problem occurs. Then take a black sheet of paper, cut a small rectangle in it and then hold it far enough away to it is just no longer visible in the image (like a giant lens hood). If the purple goes away then this is likely what the problem is.

    Of course it could be something else entirely.

    Good luck!

    Ken

  3. #3
    capital
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    maybe I'll give that a try..
    The main thing is I'm using the new panasonic 20/1.7 m4/3 lens, so it's probably not the image circle..

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    Member kwalsh's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Oh I'm sorry! I didn't read your post closely enough, you do say right there that you were getting ghosting with the 20 on the GH1. Yeah, you're right, it probably has nothing at all to do with a large image circle. And yes, it seems weird - I wouldn't expect it from a Panasonic designed lens on a Panasonic designed camera!

    Well that will teach me to read more carefully...

    Hope some others can give you some better ideas than mine. Probably one thing that might help for information is showing where the ghosting is relative to bright sources in the image.

    Ken

  5. #5
    capital
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Yeah no worries, my post is a bit convoluted..

    Looking into the spaces around the sensors I can see a lot of magenta colored metallic metal edges. I'm not sure exactly how both cameras differ in their configurations and why only my gh1 is doing this, but it does occur often. And yea is always in response to a strong light source..

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    Senior Member pellicle's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    looks like lens flare to me

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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Looks like flare & it is weird that it only happens only with your GH1 and not your GF1 with the same lens... Sensor difference?

    Hmmm... or Halloween ? It is cool for Halloween, but not so cool if it messes up your shot

    Robert.

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    Senior Member simonclivehughes's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Do you have any filters on the lenses?

    Cheers,

  9. #9
    capital
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    No filters...

    here are a few more examples.. full frame this time

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    Re: Purple/magenta ghosting with GH1, but not GF1?

    They seems to be where the light source is coming from.

    Options... Flare, Sensor gone wacky, setting, Hood needed or The lens mount on the body is bad... causing a leak. i.e. causing lens not mounting properly.

    I am stumped... You may have to send the GH1 back as defective.

    Good luck... Keep us posted.

    Robert.
    Last edited by lmr; 23rd October 2009 at 13:25. Reason: Spelling...

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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Wow, that's pretty extreme. Is this with the 20 as well?

    The only physical difference between the GH1 and GF1 with respect to the light path to the senor IS the sensor if everything else is matted out, so that is probably what does it. The two obviously have different software as well, but I don't see that as being able to produce such flare.

    The only real way to test it is to try two shots with the same lens on the two different bodies when the GH1 produces flare. In any case I'm glad the GF1 doesn't do it, as mine is coming shortly.

  12. #12
    Senior Member simonclivehughes's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    I am definitely not seeing this on my G1, GH1 or GF1. I think you must have an issue with your particular camera.

    Cheers,

  13. #13
    ChrisJ
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    I wonder if you have a 'protection' filter on? This is the kind of thing they can cause particularly if they need cleaning between the filter and lens. It might be the reflection of the sensor in the filter.

    Chris

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    Member kwalsh's Avatar
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    Re: Purple/magenta ghosting with GH1, but not GF1?

    Oh my goodness! That is really horrific. I think I'd try to get in touch with Panasonic service and at least see if you can't send them the examples (using the Panasonic 20, don't mention your other non-standard glass). That doesn't seem normal or acceptable.

    One interesting thing - from just these three samples it seems to occur when the source is just out of the frame - as if there is something surrounding the sensor that is reflecting some how. Do you get the flare if the source is a bit more centered? Perhaps an interesting series of shots would be to take pictures of a bright flashlight pointed at the camera in different locations of the frame and just outside the frame.

    Ken

  15. #15
    capital
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    RESOLVED

    Thanks for the feedback everyone!

    I just did a more systematic flashlight test with just the 20mm, and it seems I was wrong to begin with… (sorry about that!)
    The GF1 DOES DO the same thing… It's just a little not as easy to prompt.

    The sensor surround of the GH1 is a configured a little different than the GF1 (and I presume the G1) to accommodate the slightly larger sensor. Whatever the difference makes the effect more noticeable.

    So I guess there's nothing wrong here...
    Just an unusual situation here where I am getting this to occur more than others..

    The magenta flares are the same color as the sensor coating and things are reflecting around in there a little…

    btw, the 20/1.7 is awesome!

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    Re: RESOLVED

    Quote Originally Posted by capital View Post
    The magenta flares are the same color as the sensor coating and things are reflecting around in there a little…
    That would be the UV/IR cut (plus AA) filter stack that is visible to you (through the thin ultrasound shake cover glass which is also coated on both the sides). It (the UV/IR cut AA pack) has a strong IR reflecting, multicoated dichroic filter (in addition to the blue green absortive IR filter in that stack)surface facing away from the sensor. The sensor itself is ~1cm away from the shutter.

    Interestingly, the Olympus-D 17/2.8 (and the zooms) has strong IR reflective coatings on the front and the rear elements. I would think that is the case with the Pana 20/1.7 as well.

    I can not understand any logical reasoning behind such coatings on the rear elements of the lenses given the construction of the cameras for them.
    Last edited by Vivek; 23rd October 2009 at 15:17.

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