Any way to minimize the "louvered blinds" effect when recording through a prop?

earthsciteach

Moderator
Moderator
Any way to minimize the "louvered blinds" effect when recording through a prop?

I have a keychain 720 P video camera that does a decent job recording and is very light. I just recorded a video with the camera attached to the long nose of my 800 mm Spitfire. Totally forgot about the annoying effect of the prop! Is there anyway to minimize the scrolling vertical lines due to the prop? I guess it is a limitation of the camera.
Thanks!
 

earthsciteach

Moderator
Moderator
Yeah, I figured that's the only solution. But on the little Spit, unless the camera is pointed backward, there really isn't a place to mount it and not impact the flight characteristics drastically. Oh, well!
 

colorex

Rotor Riot!
Mentor
I think the only way is mount it somewhere else.

+1

You'll have to mount it on the wing, but remember to balance the other wing... Depends mostly on what you want to see. If you want to see a part of the plane in the video, you could mount it on the tail. If you want to film the ground, you can place it on a custom mount on the wing, which faces slightly downwards...
 

earthsciteach

Moderator
Moderator
The Spit definitely does not lend itself to wing mounting! I have spent months and countless repairs/modifications just to get it flyable. Now, she flies like a dream! But, she will still snap roll in a heartbeat if you aren't always on your toes. Any difference in airflow outboard of the centerline will be very dangerous.
 

PaulT

New member
Mentor
One solution is to search for a camera that can record higher than 30 fps.
How about a pod positioned above the view of the prop and on the center line of the fuselage that you can mount your camera?
Two guy wires to each wing and one fore and aft for stability and attached to a small pedestal four inches above the canopy.
Just a thought.
 

earthsciteach

Moderator
Moderator
Ah, so its the frame rate! I have a standard definition GoPro, but that is way too heavy for the little bird. I'll just have to live with the fact I can't mount my keychain camera behind the prop. Once I get my fpv setup, I guess I'll HAVE to get a GoPro 2! It never ends, does it?
 

SunShine

not crazy, just stupid
its not the fps, its the shutter speed.. just saying...
but anyways, you can use a lighter colored prop, like a orange one, that reduces the effect massively.
 

PaulT

New member
Mentor
This has been bugging me all night!
I was thinking of the Bleriot mono wing but with the need for less support.
This should be very easy to make and should have no effect on flight
characteristics but may have some effect on camera
vibration so maybe a strip of material under the camera to absorb that.

bleriotxi_se-xmc_ott07_kp.jpg
 

PaulT

New member
Mentor
I stand corrected.
At 25 fps (NTSC standard) you would have to increase your shutter speed.
I have looked at various specs for ccd cameras and see no ratings that mention shutter speed?
Curious???
 

SunShine

not crazy, just stupid
well the problem is that a camera "creates" each frame starting from the top and than going down, if you have an object moving very quickly, lets say a line (|), moving from left to right, than it you will get a frame where you have a line that looks like this \ .
so its not the actual shutter speed that is the problem, but the way that the sensor picks up and records the movement. on cameras where you can set the shutter speed to very short, you probably have a good image processor, witch again "reads" the entire frame faster, and by that avoids this problem. consumer cameras with no manual settings usually have these problems.
Edit: but do try the orange props, they do work wonders!
 

Joker 53150

Mmmmmmm, balsa.
Mentor
Reviving an old thread here, I don't know if anybody has seen this before but one of the sites which caters to GoPro cameras has a lens that is supposed to fix prop spinning issues, car wheels, etc. Here's the link to their site, complete with a demo video.

I don't know if this would work for all cameras, but it looks promising for the GoPro.
 

colorex

Rotor Riot!
Mentor
Reviving an old thread here, I don't know if anybody has seen this before but one of the sites which caters to GoPro cameras has a lens that is supposed to fix prop spinning issues, car wheels, etc. Here's the link to their site, complete with a demo video.

I don't know if this would work for all cameras, but it looks promising for the GoPro.

It's a neutral density filter, they just darken everything (like sunglasses) to make the camera expose the picture more - thus blurring the prop. There are filters available for many cameras, but IDK how they would work on KeyChain cameras.
 

fishycomics

Junior Member
Shutter issue, try using a filter. or place the cam back some. and more the propeller will go away.

you may place foam to angle the cam down to get the propeller out, or start switching the lens to a Lens D that may help out many solutions, just some
 

tramsgar

Senior Member
Dynamically adjust the camera's framerate to a number divisible by the prop's rpm. Simple as that! (Or get a glass propeller.)
 

tramsgar

Senior Member
Props are variable in rpm, a principle known as throttle control. ;)

Hence the suggested dynamical adjustment =). Perhaps It's easier just to use a fixed throttle. Nah, half-seriously a white or gray prop might turn out less annoying.