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Author Topic: What are these black spots?  (Read 6420 times)

Mark F

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What are these black spots?
« on: May 06, 2015, 05:58:22 pm »

Hi,

I use a Panasonic GH2 when I need to travel light. I would really like the camera except for the occasional black, irregular shaped spots that I get on some images, always in skin tones. The spots do not appear in the same part of the frame. It does not look like noise to me and I'm hoping someone can tell me if it is a sensor issue or whatever. I've attached two examples taken a year apart. Both are severe crops so that the spots can be more easily seen. Example 1 was at ISO 640 and example 2 at ISO 160. In eample 1 the spots are on the hand on the left and in example 2 on the women faces.

I'm thinking of selling the camera if I can't get this fixed.

Thanks.
« Last Edit: May 06, 2015, 06:00:07 pm by Mark F »
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Mark

Rainer SLP

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Re: What are these black spots?
« Reply #1 on: May 06, 2015, 06:21:54 pm »

Looks strange.

I made a search with " panasonic gh2 black spot problem " and found a few postings.

¿ Does it still have warranty ?
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ErikKaffehr

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Re: What are these black spots?
« Reply #2 on: May 07, 2015, 01:20:12 am »

Hi,

I have seen something similar when using adjustment brush in Lightroom to brighten up dark areas. Are you doing something like that?

Best regards
Erik

Hi,

I use a Panasonic GH2 when I need to travel light. I would really like the camera except for the occasional black, irregular shaped spots that I get on some images, always in skin tones. The spots do not appear in the same part of the frame. It does not look like noise to me and I'm hoping someone can tell me if it is a sensor issue or whatever. I've attached two examples taken a year apart. Both are severe crops so that the spots can be more easily seen. Example 1 was at ISO 640 and example 2 at ISO 160. In eample 1 the spots are on the hand on the left and in example 2 on the women faces.

I'm thinking of selling the camera if I can't get this fixed.

Thanks.

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Erik Kaffehr
 

pflower

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Re: What are these black spots?
« Reply #3 on: May 07, 2015, 06:22:48 am »

I agree with Erik's post.  I have seen this, not only with the GH2 but other cameras if you try and lighten underexposed areas too aggressively in Lightroom either with the exposure adjustment or the shadows adjustment (and particularly if both are used).

If, on the other hand, those spots are on the original unadjusted raw file then there may be a sensor problem, but my best guess is that the original images were underexposed and brightened to breaking point.
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francois

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Re: What are these black spots?
« Reply #4 on: May 07, 2015, 07:24:49 am »

Hi,

I have seen something similar when using adjustment brush in Lightroom to brighten up dark areas. Are you doing something like that?

Best regards
Erik


That was my first thought! It usually happens when the Auto Mask option is ON.
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Francois

Some Guy

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Re: What are these black spots?
« Reply #5 on: May 07, 2015, 10:19:13 am »

I'd take it outside and pop a shot of the clear blue sky at 1/30 at f/22 (or f/16) at ISO 100 and open the image direct and see if there is any dirt on the sensor.  If not, then suspect processing.

Only saying this because I had a bunch of junk on my sensor and had to clean it yesterday.  Mine moved around every time I turned the camera on and off and was maddening.

SG
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dbolt

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Re: What are these black spots?
« Reply #6 on: May 07, 2015, 12:18:59 pm »

My guess is way too much of the Shadow brush on underexposed subjects.  Try increasing Exposure and Highlights on the entire image then brush back Black to the areas that look too light.
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ErikKaffehr

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Re: What are these black spots?
« Reply #7 on: May 07, 2015, 04:14:33 pm »

Yes, I agree on that.

Best regards
Erik

That was my first thought! It usually happens when the Auto Mask option is ON.
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Erik Kaffehr
 

Mark F

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Re: What are these black spots?
« Reply #8 on: May 07, 2015, 06:02:24 pm »

While trying to figure this out, at some point I also realized that using the brush for local brightening can cause strange artifacts. But that is not what has happened here. I've attached screen shots of the right panels of the Develop module for both photos. In neither case was the brush used at all. Also, in both cases when I zero'd out the Shadow slider the black spots remained. I'm going to try SG's suggestion about taking a photo of the sky to see if the sensor is dirty but doubt if that is the problem. What drives me nuts is this only happens occasionally, seemingly only on flesh and in different parts of the frame. Anyway, thanks to all for trying.

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Mark

francois

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Re: What are these black spots?
« Reply #9 on: May 08, 2015, 05:22:40 am »

While trying to figure this out, at some point I also realized that using the brush for local brightening can cause strange artifacts. But that is not what has happened here. I've attached screen shots of the right panels of the Develop module for both photos. In neither case was the brush used at all. Also, in both cases when I zero'd out the Shadow slider the black spots remained. I'm going to try SG's suggestion about taking a photo of the sky to see if the sensor is dirty but doubt if that is the problem. What drives me nuts is this only happens occasionally, seemingly only on flesh and in different parts of the frame. Anyway, thanks to all for trying.



Does it also happen with another RAW converter?
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Francois

Mark F

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Re: What are these black spots?
« Reply #10 on: May 08, 2015, 09:54:21 am »

Good question. Unfortunately I only have LR & ACR so I do not know.
« Last Edit: May 08, 2015, 09:56:42 am by Mark F »
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Mark

francois

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Re: What are these black spots?
« Reply #11 on: May 08, 2015, 11:11:58 am »

Good question. Unfortunately I only have LR & ACR so I do not know.

Try to download a demo version of Capture One or any other converter.
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Francois

Mark F

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Re: What are these black spots?
« Reply #12 on: May 08, 2015, 01:32:30 pm »

For the record, I made the photos of the sky as suggested and my sensor is clean so that's not the problem. Next step is to download a trial version of Capture One.
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Mark

speedyk

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Re: What are these black spots?
« Reply #13 on: May 10, 2015, 01:39:52 pm »

Put up a RAW file and I'll try it. My G1 doesn't give me that and I only use RAW.

Lightzone is free...http://lightzoneproject.org/
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Some Guy

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Re: What are these black spots?
« Reply #14 on: May 10, 2015, 08:55:47 pm »

RawTherapee is also another free RAW converter.  http://rawtherapee.com/downloads

SG
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Doug Peterson

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Re: What are these black spots?
« Reply #15 on: May 10, 2015, 09:43:02 pm »

Definitely try Capture One. Many people use LR as a default because it is made by Adobe. It can be shocking to see how much better C1 will handle the same raw file.

But I'm obviously biased since we sell Capture One. Absolutely worth doing the free trial though and seeing the difference.

BobDavid

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Re: What are these black spots?
« Reply #16 on: May 11, 2015, 07:30:56 pm »

Doug, how does C1 do with Oly .orf files? Does it support hi-res mode?
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