Hello everyone,

I'm coming towards you as I experienced some kind of weird artefacts on low light, long exposure photography I took with the P4.
On each and every photo I shot some pixels light up. I don't know if this was due to my settings (RAW, 16:9, 5"), or this was due to something else.
It seems to me that everywhere there is dark, the camera "fills" this dark with some pixels Red, Green, or Blue.



If you have any idea please let me know.

Edit :

I had to lower the quality in ordre to post it directly on the forum, and those artefacts are very faint in jpeg (a few remain visible or the right side), but in DNG they are everywhere on the picture. I'm linking you the original on dropbox : https://www.dropbox.com/home/DJI%20Camera%20Artefacts?preview=DJI_0147.DNG

If you have any idea on what could this be, please let me know.

I cannot access the file where I am now.

It sounds like noise to me. It is most visible in the shadows so would be apparent in that frame.
What exposure settings are you using? Specifically what is the ISO?

Noise will vary from sensor to sensor but  increases with ISO. Generally the larger the sensor the better the noise characteristics and the higher you can push the ISO.

Cabansail Posted at 2017-1-19 13:19
I cannot access the file where I am now.

It sounds like noise to me. It is most visible in the shadows so would be apparent in that frame.

The ISO is set on 100 to minimise the noise. The problem, indeed, could be noise.
The shutter is set on 3", I'm using the 3D Noise Reduction, and the exposure value is set to 0.

Tell me if you need any more specs, and thanks for the help.

Having a look at the attached jpeg some of the dots seem to be hot pixels. From what I can see here mostly in the green channel. There are more than I would expect from a sensor in a DSLR but I am unaware of the threshold they use for these devices.

To test for Hot Pixels  and noise do a set of manual exposures with an opaque lens cap on. Try different ISO and Shutter Speeds. This can be done at home without flying the drone.

Just to clarify, what firmware are you running on your unit?

Cabansail Posted at 2017-1-19 14:00
To test for Hot Pixels  and noise do a set of manual exposures with an opaque lens cap on. Try different ISO and Shutter Speeds. This can be done at home without flying the drone.

I'll be conducting the tests soon ! Thanks !

DJI-Jamie Posted at 2017-1-19 16:38
Just to clarify, what firmware are you running on your unit?

I'm running on the latest firmware, I made sure my P4 firmware was up to date.

HESPzIroN Posted at 2017-1-21 00:22
I'm running on the latest firmware, I made sure my P4 firmware was up to date.

And you did not notice this with previous RAW pictures until now, correct? Just to make sure I'm on the same page, the JPG imager aren't affected? Whenever you can report back with the results of some of the testing recommended by Cabansail, it would be appreciated.

DJI-Jamie Posted at 2017-1-23 14:42
And you did not notice this with previous RAW pictures until now, correct? Just to make sure I'm on the same page, the JPG imager aren't affected? Whenever you can report back with the results of some of the testing recommended by Cabansail, it would be appreciated.

To answer your previous post;
This was the first time I've been taking RAW pictures and I noticed those hot pixels problem.
I conducted the tests Cabansail recommended, and no flaw appeared on the pictures I took.
I conducted the tests in low light condition while taking several pictures, with differents ISO and Shutter speed.
As no hot pixels appeared, I won't be posting the picture, although I can put them on Dropbox if you ask for it.
Either I couldn't conduct a good test, either the problem is fixed.

HESPzIroN Posted at 2017-1-25 14:48
To answer your previous post;
This was the first time I've been taking RAW pictures and I noticed those hot pixels problem.
I conducted the tests Cabansail recommended, and no flaw appeared on the pictures I took.

Good to hear that you were able to get it sorted. Just for reference, you had only conducted further tests and did not perform any additional updates or reapplied any firmware/ software installations?

Please let us know if the pixels come back.

DJI-Jamie Posted at 2017-1-25 15:15
Good to hear that you were able to get it sorted. Just for reference, you had only conducted further tests and did not perform any additional updates or reapplied any firmware/ software installations?

Please let us know if the pixels come back.

No I haven't updated the firmware or done any updates.
...
However, when looking at the RAW pictures on an Apple computer, hot pixels appears like crazy...
I couldn't explain why they were invisible when I first looked at the pictures on my Windows computer.
Thus I'm linking you the set of pictures I took during the test.
https://www.dropbox.com/home/DJI%20Camera%20Artefacts
The ISO was set on 100, and the shutter speed was set on 1", 2", 4", 6", 8". I had similar results with an ISO of 400.

HESPzIroN Posted at 2017-1-25 15:30
No I haven't updated the firmware or done any updates.
...
However, when looking at the RAW pictures on an Apple computer, hot pixels appears like crazy...

For some reason, the Dropbox link is not displaying the folder, can you resend the link?

It could be possible that there is either a codec or preview program discrepancy . I can see if it appears on one or both platforms on my end.

DJI-Jamie Posted at 2017-1-25 15:37
For some reason, the Dropbox link is not displaying the folder, can you resend the link?

It could be possible that there is either a codec or preview program discrepancy . I can see if it appears on one or both platforms on my end.

Here's the new link. This one should be fine : https://www.dropbox.com/sh/mp30y ... 5ize6_9c474RGqla?dl=0
If this link doesn't work, it is in the same one that at the very start of the topic.

And thank you so much for your help, I really appreciate the time you're taking to solve my problem.