Not sure what this is?

Kevin Nelson · Oct 15, 2015

Tried out my brand new Hero 4 Black and got these odd lines in the video.

Jubalr · Oct 15, 2015

Those are prop shadows caused by the position of the sun shining through the props and casting shadows on the lens.

Kevin Nelson · Oct 15, 2015

Jubalr said:
Those are prop shadows caused by the position of the sun shining through the props and casting shadows on the lens.

Prop shadows? I've been flying toward the sun for months, at all angles, before and after gimbal and never saw anything like this. What's the remedy?

Jubalr · Oct 15, 2015

Kevin Nelson said:
Prop shadows? I've been flying toward the sun for months, at all angles, before and after gimbal and never saw anything like this. What's the remedy?

I have heard it can be reduced in post editing but is difficult. It will show up with just the right angle to the sun, regardless of platform...

Rich · Oct 15, 2015

Yes, prop shadows. Did you have the lens shade installed? it's small, but may help a bit.

Acroduster · Oct 15, 2015

The shade helps a little, but lens filters work the best. ND4 to ND8 work the magic...

Kevin Nelson · Oct 15, 2015

Acroduster said:
The shade helps a little, but lens filters work the best. ND4 to ND8 work the magic...

Thanks for the advice, but how will an ND filter help? If the problem is caused by the props casting a shadow on the lens and interfering with the light coming into the camera, wouldn't the same thing happen on the ND filter? It's just a piece of tinted glass in front of the lens no?

Jubalr · Oct 15, 2015

Kevin Nelson said:
Thanks for the advice, but how will an ND filter help? If the problem is caused by the props casting a shadow on the lens and interfering with the light coming into the camera, wouldn't the same thing happen on the ND filter? It's just a piece of tinted glass in front of the lens no?

I have not seen prop shadows on my footage since using the ND8 filter I have. Like Acroduster said, I have seen posts that recommend them to help rid the problem. Regardless of the science behind it, I'm sure it would be worth a try..

Acroduster · Oct 15, 2015

What is happening is that the frequency of the blades passing over the lens approaches some small multiple of the rolling shutter frequency of the camera. When this happens, a "beat frequency" will occur. Putting an ND filter on the camera slows down its shutter speed (it automatically adjusts to let more light in) thereby increasing the multiple between the frequencies and greatly reducing the beat effect. Look under "beat envelope" here: Beat Frequencies in Sound by Ron Kurtus - Succeed in Understanding Physics: School for Champions

Kevin Nelson · Oct 15, 2015

Acroduster said:
What is happening is that the frequency of the blades passing over the lens approaches some small multiple of the rolling shutter frequency of the camera. When this happens, a "beat frequency" will occur. Putting an ND filter on the camera slows down its shutter speed (it automatically adjusts to let more light in) thereby increasing the multiple between the frequencies and greatly reducing the beat effect. Look under "beat envelope" here: Beat Frequencies in Sound by Ron Kurtus - Succeed in Understanding Physics: School for Champions

Cool. I'll give it a whirl. Thanks!

Burkeam · Oct 15, 2015

Jubalr said:
I have not seen prop shadows on my footage since using the ND8 filter I have. Like Acroduster said, I have seen posts that recommend them to help rid the problem. Regardless of the science behind it, I'm sure it would be worth a try..

What filter -make-model do you use with the gimbal. I have a nice glass one but is too heavy for the gimbal?

Adimuzio513 · Oct 15, 2015

Think most all of em make the gimbal a bit unbalanced, I use a lightweight polar pro set and I still have to use a sticky type clay to balance out the extra weight on mine. I'm debating using more to keep my camera from rolling forward too, it's not been a problem yet though. I'm just thinking it would lengthen my tilt motors life if I do it to relieve some strain holding it up all the time. Kinda sucks though cause if I add that I'll have to add more to balance, so I'm not sure if it's a good or bad idea to add the weight.

Adimuzio513 · Oct 15, 2015

Would of been great if since most folks use filters they would have included a screw on that end to use the counterweights like they have for the older Heros. Even if it was an additional option it'd be worth a few bucks for weights designed just for that purpose. Maybe next time or maybe somebody can make something similar and make a few bucks, my clay works but it's not the prettiest solution around.

Acroduster · Oct 15, 2015

I believe that the gimbal was designed with the hood in mind. That offsets some of the weight of the filter. I have not counterbalanced mine and don't intend to.

Adimuzio513 · Oct 15, 2015

Does yours droop much to the camera side when turned off? If

Acroduster said:
I believe that the gimbal was designed with the hood in mind. That offsets some of the weight of the filter. I have not counterbalanced mine and don't intend to.

not than my questions the same as above. I thought mine seemed light, but they are glass and my gimbal lays to the cam side if I don't counter the weight.

Burkeam · Oct 15, 2015

Adimuzio513 said:
Would of been great if since most folks use filters they would have included a screw on that end to use the counterweights like they have for the older Heros. Even if it was an additional option it'd be worth a few bucks for weights designed just for that purpose. Maybe next time or maybe somebody can make something similar and make a few bucks, my clay works but it's not the prettiest solution around.

I was think of using Velcro with more counter weight but it takes a lot which might be fine as I'm rally starting to take more photos then video

Adimuzio513 · Oct 15, 2015

Yea I've went back and forth a few times from adding the weight to taking it off, it's fine either way just want to keep the motors smooth as long as I can. Can't say whether the weights good or bad really, I've not seen 3dr say one way or the other, I'm sure they use filters though.

flabango · Oct 15, 2015

I've experience prop shadows but never like that. Are you guys sure they're prop shadows?

Sent from my iPhone using Tapatalk

Burkeam · Oct 15, 2015

Nor I, however those lines look relative the landscape/angle on the later part of the video. At first I was thinking a balance issue maybe affecting the HDMI connection but it is not always across the whole screen?