Please select Into the mobile phone version | Continue to access the computer ver.
These pixels ain't so HOT!
1229 19 2015-10-18
Uploading and Loding Picture ...(0/1)
o(^-^)o
Phuglie
First Officer
Flight distance : 45226 ft
United Kingdom
Offline

These Pixels Ain't So HOT!


The four pictures below were taken today with my P3pro - this is the first time I've used it to take photos ... the small tri-cluster of red squares highlight an area I compared between the four images, which are shown further below. There were many other areas on the photographs, but I chose these as they are visible on all four images.
My observations are that:
  1. The position of the odd pixels is the same for each photograph
  2. The colours of the odd pixels are not the same for each image
  3. The odd pixels are only visible on lighter areas, such as the sky
My conclusions are:
  4. The use of a third-party ND filter 'insert' may be the cause of the anomaly
  5. The UV lens filter may need thorough cleaning
  6. The lens, itself may need cleaning
  7. Further investigation required...
Hot-Pixels_01.jpg
Hot-Pixels_02.jpg
Hot-Pixels_03.jpg
Hot-Pixels_04.jpg
Zoom_01.jpg
Zoom_02.jpg
Zoom_03.jpg
Zoom_04.jpg
2015-10-18
Use props
JtrJr-UAV Pilot
Captain
Flight distance : 4341 ft
United States
Offline

Phug,

I had a similar experience when using an ND filter that just sits behind the stock lens cover. After looking over the filter itself there were tiny little marks on the filter. I'd probably take a very close look at the filter. I removed the filter and took some photos and didn't see the anomaly.

Jerry
2015-10-18
Use props
Geebax
Captain
Australia
Offline

I doubt they are dirt on the ND filter or lens, as they would most likely show up as dark spots, not light ones and the colour would not vary. My guess is that they are 'stuck pixels' that have not been mapped by the camera firmware. Virtually all cameras have these, but the camera should take care of them.
2015-10-18
Use props
JtrJr-UAV Pilot
Captain
Flight distance : 4341 ft
United States
Offline

Geebax Posted at 2015-10-18 17:22
I doubt they are dirt on the ND filter or lens, as they would most likely show up as dark spots, not ...

Geebax,

That may very well be. I'm very uneducated when it comes to photography and cameras. In my case, and it did look quite similar, it was definitely the ND filter. It wasn't dirt, it was more like tiny indentations in the filter. The filters came in a regular envelope and were supposed to be between two pieces of cardboard but we're not when I received them. Personally, I think they were indentations from abuse in the mail. Certainly no expert though.

Jerry
2015-10-18
Use props
gregg1r
First Officer

United States
Offline

What you are seeing could be dead pixels in the CMOS sensor. Try shooting against a white wall that is well lit and see if they're still there. Have your Phantom 4-6 feet away from the wall.

Are you able to perform a pixel count in your imaging program, so you can repeat getting back to the same area? You'll need to map the locations by pixel x and Z axis to get repeatable results.
2015-10-18
Use props
Geebax
Captain
Australia
Offline

Jerry, it is the light colour of the spots that triggered my thoughts, because any defect in the ND would be more likely to produce dark spots.
2015-10-18
Use props
JtrJr-UAV Pilot
Captain
Flight distance : 4341 ft
United States
Offline

Geebax Posted at 2015-10-18 20:16
Jerry, it is the light colour of the spots that triggered my thoughts, because any defect in the ND  ...

Geebax,

Yes, very possible. As I said, I've got no expertise in this area whatsoever! I just figured I'd share my thoughts because of the issue that I had with my ND filter. No biggie, we're all here to help one another!

Jerry
2015-10-18
Use props
Swedrone
Captain
Flight distance : 10273494 ft
  • >>>
Sweden
Offline

what ISO speed please?
2015-10-19
Use props
rodger
Captain
Flight distance : 15812070 ft
  • >>>
United States
Offline

Try another filter Phuglie and  see if the spots are still there? If they are it may be the sensor? Hope not!.
2015-10-19
Use props
rodger
Captain
Flight distance : 15812070 ft
  • >>>
United States
Offline

Try another filter Phuglie and  see if the spots are still there? If they are it may be the sensor? Hope not!.
2015-10-19
Use props
Phuglie
First Officer
Flight distance : 45226 ft
United Kingdom
Offline

rodger Posted at 2015-10-19 15:06
Try another filter Phuglie and  see if the spots are still there? If they are it may be the sensor?  ...

Equally I can twist the filter round to see if the spots move???
2015-10-19
Use props
rodger
Captain
Flight distance : 15812070 ft
  • >>>
United States
Offline

Phuglie Posted at 2015-10-19 12:40
Equally I can twist the filter round to see if the spots move???

That will work also.
2015-10-19
Use props
Jay_Bit
lvl.4

United States
Offline

Now that's a picnic blanket!!
2015-10-19
Use props
Phuglie
First Officer
Flight distance : 45226 ft
United Kingdom
Offline


This comes under my conclusion 7. Further investigation. Also included will be having a closer look at the video footage taken frame by frame.
2015-10-19
Use props
liningiv
Second Officer
Flight distance : 329409 ft
United Kingdom
Offline

This is not dust on the filter, it would be too blurred to register on the sensor.
It could be dust on the sensor, but if only 2 or 3 pixels wide are involved then the dust is microscopic.  Less than 1/4000 inch.  And the camera is sealed anyway.
I think you have either stuck pixels or dead pixels.
Take a picture in .dng of a piece of white card then examine at 100%.Dont use .jpeg as this will apply sharpening automatically and the spots will become unclear.

If the pixel is dead it will show black, if it is a stuck pixel it will be red or green or blue.
If it does not show up using white card then try black card and again examine.

Very easy to edit these specks though using clone stamp tool, in Photoshop or Aperture etc.  I have to use it with my DSLR shots if there is dust on the sensor, but the dust spots are normally about 10 to 20 pixels wide/long.  Dust on the lens or a filter never shows up, unless taken virtually into a strong light or oblique to the light.  I would advise against trying to remove the filter and cleaning the lens, it is multicoated and quite easily scratched.
2015-10-19
Use props
CaveDrone
Second Officer
Flight distance : 11549 ft
United States
Offline

My two cents,  looks like bad pixels on the camera,  same place in the photos regardless of image.....
2015-10-19
Use props
Willie Wonka
First Officer

United States
Offline

Bad pixels, shoot a black page and a white page and see if they match.

The pictures you showed are pixelated too much to examine, maybe upload higher quality as in 2mb.
2015-10-19
Use props
rodger
Captain
Flight distance : 15812070 ft
  • >>>
United States
Offline

Phuglie Posted at 2015-10-19 13:01
This comes under my conclusion 7. Further investigation. Also included will be having a closer loo ...

Hope for the best. You can get rid of the spots in Post. Pain and time consuming.
2015-10-20
Use props
Phuglie
First Officer
Flight distance : 45226 ft
United Kingdom
Offline

rodger Posted at 2015-10-20 13:52
Hope for the best. You can get rid of the spots in Post. Pain and time consuming.

I only picked 3 that were consistent between the 4 images - there were many, many more! I shall try processing the dng files through the cleaner offered by DJI and see what that does.
2015-10-20
Use props
rodger
Captain
Flight distance : 15812070 ft
  • >>>
United States
Offline

Phuglie Posted at 2015-10-20 09:06
I only picked 3 that were consistent between the 4 images - there were many, many more! I shall tr ...

Let us know what you find. I hope it is not the Sensor. How old is the camera? You may want to send it back to DJI for their inspection. You do realize that you are going to look for those spots every time you take a photo. Human nature.
2015-10-21
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules