9 Orange Spots during Shoot (GH4) at DVinfo.net

Go Back   DV Info Net > Panasonic P2HD / AVCCAM / AVCHD / DV Camera Systems > Panasonic LUMIX G / GF / GH / GX Series

Panasonic LUMIX G / GF / GH / GX Series
4K and AVCHD on a Micro Four Thirds system camera with interchangeable lenses.


Reply
 
Thread Tools Search this Thread
Old October 25th, 2015, 08:12 AM   #1
Major Player
 
Join Date: Nov 2013
Location: Liverpool
Posts: 495
9 Orange Spots during Shoot (GH4)

Hi All,

On the image below, you can see 9 orange spots that have become illuminated during an outdoor video shoot for a wedding.

http://i1379.photobucket.com/albums/...pszxoelubf.png

Does anyone know if this is due to the sensor, or to do with the aperture of my camera or lens? I've done a bit of reading about this issue, and it seems I'm not alone. Fortunately, I have shot with it since with no problems.

I do wonder if this will happen again though, and if it does, I guess I will need to return it.

Thanks to anyone who is more aware than I am and can share details regarding the issue.

Kind regards,

Craig
Craig McKenna is offline   Reply With Quote
Old October 25th, 2015, 09:00 AM   #2
Major Player
 
Join Date: Dec 2005
Posts: 848
Re: 9 Orange Spots during Shoot (GH4)

Did you have a filter on the lens and if so what type of coating does it have?
Jim Michael is offline   Reply With Quote
Old October 26th, 2015, 05:03 AM   #3
Major Player
 
Join Date: Nov 2013
Location: Liverpool
Posts: 495
Re: 9 Orange Spots during Shoot (GH4)

I was shooting with the 12-40mm f/2.8. No filter, but obviously it was raining. Could the rain have caused the dots?

Thanks Jim.
Craig McKenna is offline   Reply With Quote
Old October 26th, 2015, 06:45 AM   #4
Major Player
 
Join Date: Dec 2005
Posts: 848
Re: 9 Orange Spots during Shoot (GH4)

OK that's interesting. It may be that a drop or two on the front element acted as a tiny lens to form the smaller image of those orange buoys. Usually defects on the front element have little effect on an image. Were you at the shorter end of the zoom? It should be pretty easy to test the theory with a couple of drops of water and a point light source.
Jim Michael is offline   Reply With Quote
Old October 26th, 2015, 08:36 AM   #5
Major Player
 
Join Date: Nov 2013
Location: Liverpool
Posts: 495
Re: 9 Orange Spots during Shoot (GH4)

Quote:
Originally Posted by Jim Michael View Post
OK that's interesting. It may be that a drop or two on the front element acted as a tiny lens to form the smaller image of those orange buoys. Usually defects on the front element have little effect on an image. Were you at the shorter end of the zoom? It should be pretty easy to test the theory with a couple of drops of water and a point light source.
That sould make sense, Jim. Thanks. I don't think I was at the extreme wide of the lens, probably somewhere in the middle. It's hard to say, as it was so long ago that I filmed this.

Thanks though - I haven't noticed it since, so the sensor I can assume is fine. I think what you have said makes a lot of sense too. I'll check the footage again to see if I can find any other issues arising on that day to see if it was just the buoys or not... they seemed to be pretty luminous in the footage though, frustratingly.
Craig McKenna is offline   Reply With Quote
Old October 27th, 2015, 07:52 AM   #6
Major Player
 
Join Date: Apr 2008
Location: Sydney Australia
Posts: 899
Re: 9 Orange Spots during Shoot (GH4)

If you are talking about the orange/pink dots up around the tree line and into the sky I'll tell you exactly what it looks like to me. I've seen almost identical spots on the Sony EX cameras. We were told that they needed the sensor blocks replaced. A brilliant techo I know said lets have a look.

Using high power magnification he discovered that it was actually minute particles sitting on the sensor surface. He actually went to a special surgical positive pressure clean room and used a fine surgical vacuum sucker to suck out the particles and lo and behold the spots disappeared. Way cheaper than new 3 CCD blocks. If the dots get worse as you close the iris down and nearly or totally disappear when the lens is wide open I would think this would almost confirm the case. Point the camera at a bright light source and stop right down to check the theory.

How easy is it to clean the sensor on a GH4 I wouldn't know but I would be checking it out for sure.

Good luck

Chris Young
CYV Productions
Sydney
Christopher Young is offline   Reply With Quote
Old October 27th, 2015, 01:51 PM   #7
Inner Circle
 
Join Date: Feb 2007
Location: Apple Valley CA
Posts: 4,866
Re: 9 Orange Spots during Shoot (GH4)

Given the orange buoys, and the spots being the same color and roughly the same distribution, I'd vote for a reflection internally on one of the lens elements. Some Sony video cams had a "blue dot" issue with bright lights at certain focal lengths - I experimented and found it was something causing a reflection in the lens, again, only at certain focal lengths, but definitely repeatable, you could actually produce multiple dots at just the right spot as another element could pick up on the first reflection on the other element surface...

I'm guessing that the rather "bright" orange probably stood out against the grey and green "background", and one of the lens element surfaces caused it to "ghost" appear on an internal lens surface, which was then captured by the sensor.

Sometimes cameras catch some "strange" phenomena that can ultimately be traced to shutter abnormalities, internal lens reflections, and I suppose sometimes "real ghosts" <wink>. Happy halloween...
Dave Blackhurst is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Panasonic P2HD / AVCCAM / AVCHD / DV Camera Systems > Panasonic LUMIX G / GF / GH / GX Series

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 03:11 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network