Whoa! Crazy OLPF flare...

[Larry Gebhardt]

This issue concerns me as I often shoot with strong backlight, and keeping the sun out of the shots is not always an option.

I downloaded the shot that started this thread, and I am puzzled by the pattern of the "flare". It almost looks like (if I can remember my high school physics) a diffraction grating pattern with the even spacing and the matrix of hotter "dots". I don't think (and this is just my thought) that is is simply the internal reflections of the OLPF and the back of the lens...or even the bouncing around of the sun's image in between the sensor and the OLPF...something is causing the pattern. I would really welcome other theories here.

As far as the shot of the candles...I also think that the red dots there are the same as in the shot looking into the sun...I think (and again, just my theory) that if it were true lens flare, the red coloring of the dots would vary in color as it does with normal flare...it appears that the Magenta colored sensor is causing the coloring of the 'dots'...but what is causing the regular spacing of the dot's themselves?...am I missing something fairly simple?

Larry... where is Jeff Kreines when we need him... Gebhardt (Ok I lurk on CML also)

 

[Larry Gebhardt]

Thinking a bit more on the candle shot...this "flare" for want of a better word, I think could be the reflections back and forth between a front optical flat filter and the front element...I guess I am asking if one was used in this shot ,as that could explain it...but not the original post's flare problem.

Trying to figure it out.

Larry

 

[Rainer Fritz]

Thinking a bit more on the candle shot...this "flare" for want of a better word, I think could be the reflections back and forth between a front optical flat filter and the front element...I guess I am asking if one was used in this shot ,as that could explain it...but not the original post's flare problem.

Trying to figure it out.

Larry

We used a 25mm Ultraprime, not filtered in the front. Would be interesting to test it with a Masterprime because of their linear projection to the chip... We shot a feature 2 month long, interiors and exteriors, and had one time a minor issue with the refelctions might be in the OLPF, but no problem at all... If there is time I will put in a MP to see if there is a difference....

regards
rainer

 

[Johnbutler]

I've seen this artifact with other cmos cameras. It pops up on the Sigma DP1 all the time.

 

[zak forrest]

I've shot into light sources, candles, and directly into the sun plenty of times and never seen this pattern! What's going on..

 

[Charles Angus]

Sigma DP1 is a Foveon sensor, not a CMOS, I believe. My 20d has never done this, and I like putting the sun in/on the edge of shots...

 

[Johnbutler]

Sigma DP1 is a Foveon sensor, not a CMOS, I believe. My 20d has never done this, and I like putting the sun in/on the edge of shots...

The Foveon sensor IS a CMOS, to clarify. It is a special CMOS sensor manufactured by foveon, not a different type of sensor. Videos taken from the DP1 even have RS artifacts. The 20d probably has superior image processing in this regard, like p&s digital cameras that remove the vertical ccd smear from their images.

 

[Sebastian Cramer]

I had the exact same problem with Zeiss Superspeeds open with no filters and nothing in front of the lens. It was a 180° dregrees turned reflection on the car front lights, very sharp and nothing you would see on 35.

 

[Sebastian Cramer]

Mine was not a pattern its the same effect like post #12 of rainer, which is also a 180° degree rotation of the highlight.

 

[Simon Valderrama]

I remember something similar in the Caludio Miranda's test.
Too much a shame the test was erased ... wonder if Claudio will ever return in this board.

 

[zak forrest]

ahahahaha

 

[Simon Valderrama]

found this, a report of Claudio Miranda's test:

"1) red flare artefacts (ugly ones) caused by the IR/LP filter in front of the sensor. "

full post here:

http://forums.creativecow.net/readpost/242/517

 

[Ed Watkins]

Did this issue ever get resolved? I just spent a highly frustrating weekend having my sunrise/sunset shots ruined by this grid like 'flare'.

It was present on all my nikon lenses. Worst on the 17-35mm and 80-200mm.

Is it a back focus issue? Why do some people see it and others don't?
I seem to be getting it on every shot I shoot with a single strong focused light source facing into the lens (sun, spot light, head lamp).

Build 16.