fansd60707a2
lvl.1
Germany
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I'm also seeing the red spot in all my footage and DNG photos. I also bought the Mavic specifically for RAW photography. My Mavic is currently at DJI because of a decentered lens, so I expect the camera will be exchanged, and I'll see. But I expect the hot spot will still be there, because it's a design flaw. Let me explain.
From my 13 years of experience in RAW DSLR photography, including a Nikon D70 modified for IR photography, I think I recognize the effect. It shows up to various degrees depending on the lens used. My guess is we're seeing an infrared hot spot on the Mavic, caused by the combination of the following:
- the IR filter in front of the sensor is probably too weak or has a cut-off wavelength that is too high
- the optical design of the lens emphasizes the center of the image for high wavelengths
The fact that the hot spot does typically not appear in Jpg images proves that DJI is apparently aware of this flaw and adjusted for it in the in-device image processing, but is not able to do the same for video. And as DNG always records the raw sensor data, it can't be fixed for DNG images as well. And that's what we're seeing.
I see two possible fixes:
- DJI has to change everyone's camera against one with either a fixed IR filter, lens, or both
- in the meantime, an additional IR cut-off filter in front of the lens could also help as a temporary workaround
As I said, I don't have my Mavic here at the moment. Can someone test if the camera can see infrared light sources, like from a TV remote? If you point an IR remote at the camera, does it's LED show up with moderate brightness (which would indicate a strong IR filter in front of the sensor), or does it appear completely white (which would indicate a weak IR filter)?
Maik |
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