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Sometimes I get a lila-purple touch in pictures from the reflections
1670 28 2017-8-23
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stiibu
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Hi DJI Forum, in general I am happy with the picture and video quality of my MAVIC. But sometimes under certain circumstances and objects I take a picture I get the following issue. Not sure if this is "normal" or not.

First I recognized it when I made some pictures of my fresh washed and polished car. I have a lightning red (misano-red) AUDI. As you can see on the pictures the sun reflections tend to go into a purple touch. First I thought it is because of the AWB setting "sunny". But today I tried all possible manual camera setting combinations and I dont get it away. I can reduce it somehow if you can to a manual color temperature of 6.500 and above.

Then by coincedent I took a picture into my garden against the sun and I saw in the lense blure effect a horizontal purple line which has the same lila / purple color. Looks also like an reflections. Of course I had the cimbal cover dismounted and no filter on the Mavic.

Question: Is this normal in this kinde of extreme situations (with the color of the car and against the sun) ?

today test

today test

today test manual

today test manual

1. Try with AWB sunny

1. Try with AWB sunny
2017-8-23
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stiibu
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the last picture is the picture where i noticed it the first time ... the picture 1 and 2 were taken today with the settings: > Stil +1   0   +1/ > D-Cinelike > Farbtemperatur manuell auf 6.700
2017-8-23
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Ex Machina
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Yes, normal: https://en.wikipedia.org/wiki/Lens_flare
2017-8-23
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stiibu
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here another picture with the zoomed area

IMG_0075 (Medium).PNG
2017-8-23
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Ex Machina
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stiibu Posted at 2017-8-23 12:35
here another picture with the zoomed area

Might help a bit if you pull down the saturation and sharpness.
2017-8-23
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Asainz320
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I agree with ExMachina, the saturation on these shots looks way high. The one on the first picture I would blame it on the glare.
2017-8-23
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stiibu
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I did a serie of test shots where I adjusted all and each parameter from MAX to MIN ... the color temperature and the 3 values for sharpness, contrast and saturation - each from +3 to -3.
With the setting >
> Stil +1   0   +1
> D-Cinelike
> Color temp 6.700
I was able to produce these pics where the issue was minimized, but still there
2017-8-23
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stiibu
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.. and even this lila/purple horizontal line in the picture against the sun is normal ?
IMG_0050x (Large).jpg
2017-8-23
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Ex Machina
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stiibu Posted at 2017-8-23 21:58
.. and even this lila/purple horizontal line in the picture against the sun is normal ?

Yes, that's called lens flare -- read the wikipedia article link I posted in my first response to understand the issue. You get the effect whenever a bright light source like the sun directly or obliquely hits the lens, and sometimes with reflections of a bright light source.
2017-8-24
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stiibu
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Ex Machina Posted at 2017-8-24 05:50
Yes, that's called lens flare -- read the wikipedia article link I posted in my first response to understand the issue. You get the effect whenever a bright light source like the sun directly or obliquely hits the lens, and sometimes with reflections of a bright light source.

ok, and any idea why my red car has this lila/purple areas ? Is this normal behaviour that extrem red objects trend this way ? I dont see it with other things.
2017-8-24
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stiibu Posted at 2017-8-24 09:14
ok, and any idea why my red car has this lila/purple areas ? Is this normal behaviour that extrem red objects trend this way ? I dont see it with other things.

I'm guessing it's a combination of things, the brightness, over-saturation to the point of posterization, the generally already overcooked jpg profile the camera outputs, and an out-of-gamut condition. It's hard to tell with jpg output because as I've said, DJI's jpg profiles are not very neutral. I suspect a RAW version would have had better dynamic range to work with and this is one of those cases where DJI jpg just fall down.

When I look at your third example in Lightroom, enable proofing and turn on gamut warnings I get this, where the blue represents the lower end of the gamut limit and the blinking bright red, the higher. An out of gamut condition means that some colors cannot be represented accurately by your display and so clip.
gamutme.gif
2017-8-24
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stiibu
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The RAW pictures also contain this lila/purple trend. So I did some more test series where I shot a picture with each possible combination for sharpness, contrast and saturation (going step by step for each setting from +3. +2. +1. 0, -1, -2, -3).
Bottomline ... even with saturation -3 this effect is still there. Whatever combination I did, the lila/purble areas stay there.
Just to make sure ... it is a extrem color of the car. Here a picture I took with my SAMSUNG A5 mobile phone. Thats perfect and this is how the car looks in "real". This is how I wish also the Mavic would shoot it straight away, I do not want to rework every picture in post-processing. If a normal SAMSUNG A5 mobile phone can do it ok, why not the MAVIC ?

20170814_174632 (Large).jpg
2017-8-24
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DJI Thor
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That is the normal light reflect. Besides, did you fly the drone with the gimbal cover?
2017-8-25
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Ex Machina
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stiibu Posted at 2017-8-24 21:45
The RAW pictures also contain this lila/purple trend. So I did some more test series where I shot a picture with each possible combination for sharpness, contrast and saturation (going step by step for each setting from +3. +2. +1. 0, -1, -2, -3).
Bottomline ... even with saturation -3 this effect is still there. Whatever combination I did, the lila/purble areas stay there.
Just to make sure ... it is a extrem color of the car. Here a picture I took with my SAMSUNG A5 mobile phone. Thats perfect and this is how the car looks in "real". This is how I wish also the Mavic would shoot it straight away, I do not want to rework every picture in post-processing. If a normal SAMSUNG A5 mobile phone can do it ok, why not the MAVIC ?

This photo does indeed look better, but it also runs outside of the gamut, this time mostly on the high-end. I can still see the color shift on the hood and fender areas, but it's much less objectionable.

Can you post a RAW file shot somewhere for us to look at?

2017-8-25
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stiibu
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Of course I did NOT use the Gimbal Cover .. what a question :-) As written the "good" foto was taken with my SAMSUNG A3 mobile phone. This works fine. And the lila effect is from any perspective I did the fotos from my AUDI with the mavic. It was around 5-6 o`clock in the evening. Here are 2 RAW images from the MAVIC from that session:
https://www.dropbox.com/s/lfj58a60eifs7gw/DJI_0229.DNG?dl=0
https://www.dropbox.com/s/hr2pxq58g9mdtgz/DJI_0230.DNG?dl=0
2017-8-25
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stiibu
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so the RAW looks ok, means the lila effect comes from the MAVIC software while creating the JPGs. BUT, as said, I tried in a second session two days ago ALL possible settings (I shot dozens of picutures): various manual temperature, all color profiles and the different styles one by one from +3 to -3. The lila reflection can be reduced with some settings, but is always present. To me it looks like a software bug in this kind of extreme color situation, not a phys. camera issue since the RAW pics look good.
2017-8-25
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stiibu
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these are the org. MAVIC JPGs to the above RAWs:
https://www.dropbox.com/s/rm5loan5b47jrjo/DJI_0229.JPG?dl=0
https://www.dropbox.com/s/1u2z3i30lk4p91n/DJI_0230.JPG?dl=0

I shot them in color "NORMAL" mode, AWB "sunny" and Style +1 0 0
2017-8-25
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Ex Machina
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stiibu Posted at 2017-8-25 11:28
so the RAW looks ok, means the lila effect comes from the MAVIC software while creating the JPGs. BUT, as said, I tried in a second session two days ago ALL possible settings (I shot dozens of picutures): various manual temperature, all color profiles and the different styles one by one from +3 to -3. The lila reflection can be reduced with some settings, but is always present. To me it looks like a software bug in this kind of extreme color situation, not a phys. camera issue since the RAW pics look good.

Ok, that's what I suspected. DJI's jpg processing is kind of an iffy thing where in some scenarios the processing profile works to your advantage, other times, not so much, which is why most of us shoot RAW and apply our own levels of sharpening, saturation, contrast curves, noise reduction, etc.

Have you tried shooting the car with the latest firmware that came out this week? The release notes list "Improved image quality" but it's unclear what that means, could be something like further tweaks to accommodate a known vignette issue or could be improved jpg output -- I haven't flown with it yet but hope to this weekend.
2017-8-25
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Ex Machina
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As far as the lila reflection itself, I'm going to guess that's the result of your super-shiny red car mixing with the reflected blue sky -- I bet on overcast days it goes away.
2017-8-25
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stiibu
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All pictures shown here were so far (above) were taken with FW .900.
This morning I tried some more in front of my house with the new FC .1000 - but is was aroud 12:00, at high noon - not as before at late afternoon (will try it later again when the sun is a littler lower). Again, same settings as last time : Manual temperatur 6.600K - Color Profile NORMAL - Style +1 0 0
From my first look it looks better. I also tried a ND16 filter in some other shots, but that hasn't made any difference. What do you think ?

26.8. Test 1 (Large).jpg
26.8. Test 2 (Large).jpg
2017-8-26
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stiibu
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and from the front - sun is coming from upper right side

26.8. Test 3 (Large).jpg
2017-8-26
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Ex Machina
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stiibu Posted at 2017-8-26 05:18
and from the front - sun is coming from upper right side

Are these DJI jpgs from .1000? If they are then that's quite a difference!
2017-8-26
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stiibu
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YES, the latest pics posted above are the DJI MAVIC JPGs done today with .1000 FW (at 12:00 noon) in NORMAL mode.  To me they also look better as the ones I did before with .900.
Later this afternoon at around 6 pm I did some more tests and also toggled between color Mode D-CINELIKE, D-LOG, NORMAL, TRUE Color ... see below:
2017-8-26
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stiibu
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D-CINELIKE
DJI_0429 (Large).JPG
2017-8-26
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stiibu
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D-LOG .......

DJI_0430 (Large).JPG
2017-8-26
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stiibu
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NORMAL .....

DJI_0431 (Large).JPG
2017-8-26
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stiibu
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TRUE COLOR

DJI_0432 (Large).JPG
2017-8-26
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stiibu
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Summary: Even the NORMAL above is slightly over exposed, to me it looks like they improved with .1000 FW at least the NORMAL mode for my scenario with the red car. D-CINELIKE color scheme still shows the magenta trend.

Personally I would go for the D-CINELIKE scheme, since all the other colors (greens, etc) are great and I like this as it looks like, but unfortunatelly it cannot be used for my car. I am also in contact with DJI Support and will give them access to these samples of JPGs and RAWs that they may improve also the D-CINELIKE scheme.
2017-8-26
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stiibu
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This is the link to the RAW file from the last picture posted here of my AUDI (from the side)
https://www.dropbox.com/s/83bqb9xm98vc2qb/DJI_0429.DNG?dl=0
2017-8-27
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