Coloured dots appearing in photos
4587 18 2019-5-12
Uploading and Loding Picture ...(0/1)
o(^-^)o
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Recently I have been trying to capture some nice sunset pics at my local park but after uploading the pictures onto my laptop I have noticed that in some of my photos that there are blue and red dots appearing in them (there has been a few white and other colours). I'm thinking because I had my shutter open for a while due to the lower light that potentially those areas have been blown out of something has happened to them because of having such a high shutter in low light. Another possiblity was that I recently went travelling with it and I have only noticed it since coming back so potentially the camera got damaged? Don't think this is likely however as they only appear in the low light photos. (These photos are also zoomed in)

Also I haven't put this in Camera Support because so far I believe it is human error that has caused this.

Any help would be great, thanks!



Screen Shot 2019-05-13 at 4.48.10 pm.png
Screen Shot 2019-05-13 at 4.48.37 pm.png
Screen Shot 2019-05-13 at 4.48.58 pm.png
Screen Shot 2019-05-13 at 4.51.10 pm.png
2019-5-12
Use props
Charissa
First Officer
Flight distance : 689334 ft
South Africa
Offline

I don,t see blue or red dots on the images. If you opened this in a photo editor like Lightroom, the blue and red could be under and over exposure values, that you see in the editor, but not the image. This is to show you where your image is over or under exposed (red for highlights, blue for shadows.)

If not, then please circle the areas that you are referring to, as it is not visible on my side.
2019-5-14
Use props
A J
Captain
Flight distance : 13864580 ft
  • >>>
United Kingdom
Offline

Yep, I too can't see any coloured dots in the images
2019-5-14
Use props
Ken Storm
Second Officer
Flight distance : 178583 ft
United Kingdom
Offline

Nor I - No dots for me.
2019-5-14
Use props
Lamplighter55
Second Officer
Flight distance : 538596 ft
United Kingdom
Offline

There are indeed as you say some 'hot pixels' showing in your shots. I would suggest shooting some stills and footage in broad daylight against a similar view of a constant texture or coloured/lit surface - and see if the 'dots' still appear. If not then you can put it down to the original footage being shot in low light and the raised ISO causing noise off the capture chip being amplified. It can be the case that capture chips get 'stuck pixels' because the read-off (per frame cycle) has not reset some of the pixel bins. Another possibility is dirt on the lens causing a side light refraction and again creating an erroneous capture by the camera chip. Exposing the capture chip to an even field of bright light should 'reset' the stuck pixels - if not then you have a faulty capture chip with 'dead pixels'. This happens even on high end DSLR chips but is often mitigated in software by pixel binning at the point of capture - basically getting the mean value for each pixel from a set of 4 adjacent pixels (if the returned value is 'irrational').

2019-5-14
Use props
Bob Brown
Second Officer
Flight distance : 4209662 ft
  • >>>
United States
Offline

I see them clearly in the lower lh side of the last picture. strange!
If you are using a ND filter... remove it, clean the lense and re-shoot without it.
If it persists, I suggest opening a case with DJI support.



2019-5-15
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Charissa Posted at 5-14 02:17
I don,t see blue or red dots on the images. If you opened this in a photo editor like Lightroom, the blue and red could be under and over exposure values, that you see in the editor, but not the image. This is to show you where your image is over or under exposed (red for highlights, blue for shadows.)

If not, then please circle the areas that you are referring to, as it is not visible on my side.

They were visible before opening on lightroom. After importing the photos from sd card they showed up. They're definitely there, as you see below someone has zoomed into some of them.

I'm thinking it probably is however due to the lighting of the shots.
2019-5-16
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Lamplighter55 Posted at 5-14 03:46
There are indeed as you say some 'hot pixels' showing in your shots. I would suggest shooting some stills and footage in broad daylight against a similar view of a constant texture or coloured/lit surface - and see if the 'dots' still appear. If not then you can put it down to the original footage being shot in low light and the raised ISO causing noise off the capture chip being amplified. It can be the case that capture chips get 'stuck pixels' because the read-off (per frame cycle) has not reset some of the pixel bins. Another possibility is dirt on the lens causing a side light refraction and again creating an erroneous capture by the camera chip. Exposing the capture chip to an even field of bright light should 'reset' the stuck pixels - if not then you have a faulty capture chip with 'dead pixels'. This happens even on high end DSLR chips but is often mitigated in software by pixel binning at the point of capture - basically getting the mean value for each pixel from a set of 4 adjacent pixels (if the returned value is 'irrational').

[view_image]

Thanks, yes I don't think the pixels have died as of yet because they are only showing up in the low light photos. I will continue shooting and see what the results are. Very helpful, thanks!
2019-5-16
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Bob Brown Posted at 5-15 02:57
I see them clearly in the lower lh side of the last picture. strange!
If you are using a ND filter... remove it, clean the lense and re-shoot without it.
If it persists, I suggest opening a case with DJI support.

No filters are being used at the time of these photos, don't even own any but am planning to pick some up.
2019-5-16
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

A J Posted at 5-14 02:41
Yep, I too can't see any coloured dots in the images

I can zoom into the photos and repost them if you would like to make it clearer to see on these photos?
2019-5-16
Use props
Montfrooij
Captain
Flight distance : 2560453 ft
  • >>>
Netherlands
Offline

Looks like you bumped the ISO ?
2019-5-16
Use props
Charissa
First Officer
Flight distance : 689334 ft
South Africa
Offline

TakeFlite Posted at 5-16 20:20
They were visible before opening on lightroom. After importing the photos from sd card they showed up. They're definitely there, as you see below someone has zoomed into some of them.

I'm thinking it probably is however due to the lighting of the shots.

I also noticed them when zoomed in. Agree with the dead, stuck or hot pixels. It seems as if they are random in the image, so most probably only hot pixels, not dead ones.
Do they appear on all your images, or only long exposure or dark shots?
Hope you get it sorted.
2019-5-16
Use props
A J
Captain
Flight distance : 13864580 ft
  • >>>
United Kingdom
Offline

TakeFlite Posted at 5-16 20:22
I can zoom into the photos and repost them if you would like to make it clearer to see on these photos?

That's fine - I can see them in post 5 now. Hope you get it sorted soon.
2019-5-16
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Montfrooij Posted at 5-16 22:18
Looks like you bumped the ISO ?

I've just double checked and definitely was on 100.
2019-5-17
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Charissa Posted at 5-16 22:38
I also noticed them when zoomed in. Agree with the dead, stuck or hot pixels. It seems as if they are random in the image, so most probably only hot pixels, not dead ones.
Do they appear on all your images, or only long exposure or dark shots?
Hope you get it sorted.

Yes wouldn't be great if they're dead. I'm still pretty new to the more technical kind of stuff used to just fly it for fun now I'm trying to get more into the photography side of stuff so was just a bit unsure. Sounds like it is hot pixels. They are only appearing when shutter has been open for a while, as this was really stretching the low light capabilities and was at sunset.

Thanks for the help!
2019-5-17
Use props
Montfrooij
Captain
Flight distance : 2560453 ft
  • >>>
Netherlands
Offline

TakeFlite Posted at 5-17 23:42
I've just double checked and definitely was on 100.

Ok.
That would be my easy solution...
Are they always in the same spot?
2019-5-18
Use props
TakeFlite
lvl.4
Flight distance : 780233 ft
Australia
Offline

Montfrooij Posted at 5-18 13:01
Ok.
That would be my easy solution...
Are they always in the same spot?

No they aren't, as I said earlier some photos don't even have them when the lighting was better, leading me to believe these are hot pixels and that they have just been blown out because of the poor lighting and long shutter.
2019-5-18
Use props
Montfrooij
Captain
Flight distance : 2560453 ft
  • >>>
Netherlands
Offline

TakeFlite Posted at 5-18 13:37
No they aren't, as I said earlier some photos don't even have them when the lighting was better, leading me to believe these are hot pixels and that they have just been blown out because of the poor lighting and long shutter.

Yeah, that must be it!
2019-5-19
Use props
Aardvark
First Officer
Flight distance : 384432 ft
  • >>>
United Kingdom
Offline

TakeFlite Posted at 5-18 13:37
No they aren't, as I said earlier some photos don't even have them when the lighting was better, leading me to believe these are hot pixels and that they have just been blown out because of the poor lighting and long shutter.

I would agree with the 'hot pixel' theory, post 5 gives a good description, and the fact that all imaging chips will show these. In really long exposure imaging (Astronomy), the image chip is often cooled to -25 to -50C below ambient temperature to help overcome this along with other techniques.
2019-5-19
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules