[LRflex] Re: Bluedot Frustration...


On Jan 25, 2008, at 11:47 PM, David Young wrote:


At 25/01/2008, you wrote:
Flare due to bright light reflection on the metallic part of the camera?
Are you saying that on a second take with identical settings/light and framing the blob has disappeared? 
phx



My Philippe, but you are up early on a Saturday!
Can't be sure about same settings ... as I was a bit cavalier about my settings ... quick and dirty shots, as they say.
However, on the morning of the day we first met you and Alice, I had the same problem with a shot of Rose, taken outdoors, on the third stage of the Eiffel Tower. Still, until today, it has been a rare and unexplained occurrence. 

However, I found more about this phenomenon here: 
http://thesybersite.com/minolta/sensor-reflection/

Even more interesting is a comment found on one of the Nikon lists...
Ghosts involving a sensor reflection tend to be located away from the optical axis. Its possible to have an on-axis ghost involving a sensor reflection, but you have to have a bright spot in the on- axis image in the first place. In this case the ghost image coincides with the actual image.
On the other hand, hot spots are most pronounced when the subject matter in the center of the field is dark, but surrounded by bright stuff. Ray tracing inevitably shows that this can't be caused by a sensor reflection, and that it is instead caused by a pair of lens surface reflections.
So whether it is a reflection, off the rear element of the sensor, or if it's caused by internal lens surface reflections (it seems to be dependent on f stop) I'm still not sure. But, we learn more as we go along! 

I will make more specific tests and report back tomorrow (Saturday).
in the situation where this occurs...presumably it will be reproducible... ie every shot under those conditions... 


if you find it, then shoot 5 in a row of the same...Steve





G'night!
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David Young,
Logan Lake, CANADA

Wildlife Photographs: http://www.furnfeather.net
Personal Web-pages: http://www3.telus.net/~telyt
Stock Photography at: http://tinyurl.com/2amll4

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