Night Flights - Light Streak

lcl276 · Jan 7, 2016

Hi everyone, new to the forum however not new to the Phantom world

I've noticed that in a couple of the last night flights everytime there are streaks from the top/bottom of lights as shown in the attached cropped samples. This never used to happen and I've not changed any settings (I only take my photos at ISO100/200 and 1" and 2" shutter speeds).

It's showing up in both the JPGs and DNGs. Any ideas?

Many thanks in advance

Triakis · Jan 7, 2016

Check your lens. For high contrast scenery of relatively bright subjects your objective lens must be optically clean. By that I mean *perfect*.

lcl276 · Jan 7, 2016

I've cleaned the lens and it's spotless, not a thing on it, ruining my photos

Triakis · Jan 7, 2016

Strange, it still appears to be FOD somewhere. If you have a good, strong light source check and see through the outer element. Something may have gotten inside. You can also snap some photos at a solid background and check them for interference as well. If this is something that has just crept in there has to be intrusion or an issue with the sensor itself.

rhoffart · Jan 7, 2016

Could this be a vibration from your props? It wouldn't hurt to make sure they are perfectly balanced.

You could try a similar shot not flying.

lcl276 · Jan 7, 2016

Thanks for the replies:

Triakis - FOD?

Rhoffart - you mention balancing props - would it be worth using the set I haven't used yet to compare before balancing them? (I've never had to balance before, not on my P2V+ either, so would have to look into how to do this)

Dome · Jan 7, 2016

This is a lens cleaning problem. Unscrew UV filter and take a test shot without it, steady on a table with no props/motors on to check.
To clean use isopropyl alchool and microfiber sheet. I faced many times this issue with my Canon reflex lens filters.

rhoffart · Jan 7, 2016

lcl276 said:
Thanks for the replies:

Triakis - FOD?

Rhoffart - you mention balancing props - would it be worth using the set I haven't used yet to compare before balancing them? (I've never had to balance before, not on my P2V+ either, so would have to look into how to do this)

I came from the build side before moving to the P3P and it was part of the process to balance the props. Before gimbals a lot of the "jello" effect came from the props. So it was just natural for me to balance them before I flew my P3P. I believe a lot of the stress cracks are coming from unbalanced props. I have one of the first P3P's and never had an issue.

But back to topic ... balance them and re-shoot that picture. It's worth a try.

impilot51 · Jan 7, 2016

FOD. Stands for Foreign Object Damage. Used primarily by the military. Areas where aircraft with jet engines operate are regularly swept visually to clean up litter, pebbles, any small object that can be sucked up into the engine.

Sent from my iPhone using PhantomPilots mobile app

lcl276 · Jan 7, 2016

I will do that, many thanks. Could wind be a factor? It is the only thing I can attribute it to that isn't related to the P3P itself.

ScatSpeak · Jan 7, 2016

lcl276 said:
Could wind be a factor?

Can't imagine how wind or any prop induced jello effect could cause this... I agree with @Dome that this is likely caused by the lens/filter assembly... cleaning warranted

Triakis · Jan 7, 2016

FOD = Foreign Object Debris.
Damage comes after.

Basically anything that SHOULD not be there but is.

Jello effect is due to rolling shutter and all sorts of artifacts occur depending on shutter speed, frame rate, etc. Search for it on youtube. Propellers do some interesting things (falling boomerangs?)

In any case, take a pic at night of something bright with motors off.
If you still have the aberrations then I'd say you got fouling on one of your optical elements.

impilot51 · Jan 7, 2016

Your right. I jumped ahead thinking about the end result. We also tend to use the term interchangeably where I work. (We build fighter jets).

Sent from my iPhone using PhantomPilots mobile app

Reed L · Jan 7, 2016

First I'm no professional photographer. The second pic looks like it may be light reflection from the props. Are you using the white props or the black carbon fiber? For night shots if you have the carbon fiber props, it might make a difference, it's just a thought. You had your marking lights turned off right? Would a flat black coating under the front of the P3 make a difference?