Rolling Shutter GoPro Problem

[mattworks.com]

Hey Everyone,

I went for a flight in a T-6 (WWII fighter trainer) and captured some amazing footage using a GoPro (Hero 4)  attached to the wingtip. Unfortunately, there is some major rolling shutter + jello + wavy warp issues with the footage.

I have tried "Rolling Shutter Repair" along with "Warp Stabilizer" (in both Premiere and AE) and have had no luck so far. I have followed any advice I have been able to find to no avail. Nothing seems to fix this issue. Next time I realize I will need to shoot at a higher frame rate and probably use an ND filter as well, but the shots I captured today are once in a lifetime.

Please have a look at the video and let me know what I may be able to do. I shortened the clip to under 10secs for anyone to download and attempt to fix.

T-6 Texan GoPro Test Footage

ANY and all advice would be much appreciated and I look forward to learning how to fix this in post.

Thanks!

Matt

[Ann Bens · Accepted solution]

There are afaik 4 types of rolling shutter: skew, wobble, smear and partial exposure.

You cannot fix wobble in post.

The jello/wobble is caused by the sensor.

[rodneyb56060189]

what a bummer. nice looking plane. You must've been friends with owner / pilot to allow sticking a camera on wing. Probably suction cup ?

Unfortunately, you're stuck with what you got on that flight. But for future flights like that it might help to research a bit.

Anyway, there's weird stuff about digital film but it's primarily based on photographic cameras. Shutter speed, frame rate, F stop and ISO (white balance (color temp)) etc.

You mentioned...

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Next time I realize I will need to shoot at a higher frame rate and probably use an ND filter as well, but the shots I captured today are once in a lifetime.

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I don't have a go pro camera so I don't know what options you have re: manual control or auto control. So I'm stupid about what options you have.

Using an ND filter cuts down the amount of light coming into lens. A .3 ND cuts it down by one F stop.

That means that to get proper exposure similar to before adding ND filter you have to either increase ISO (like from 50 to 100), OR DECREES shutter speed ( like from 1/50th /sec to 1/25th Sec ).

Since tradition usually says (based on the old film camera Mitchell movement of 180 degree shutter) the shutter speed is twice the frame rate ( for example, 24 FPS is 1/48th per sec.), it stands to reason that adding an ND filter MIGHT (if your camera is automatic) LOWER your shutter speed instead of raising it as you said you wanted to do.

I think I would ( if I had your camera ) google the name of your camera and add the words AERIAL VIDEO SETTINGS, or something like that, and see what others have done !

good luck !

[rodneyb56060189]

addition:

=========

That means that to get proper exposure similar to before adding ND filter you have to either increase ISO (like from 50 to 100), OR DECREES shutter speed ( like from 1/50th /sec to 1/25th Sec ).

OR open F stop one stop.

[rodneyb56060189]

There's a cool little book (paperback) called EIGHT AMAZING ENGINEERING STORIES, that explains basically how the chip in your camera works ( among 7 other subjects )

I still don't truly understand ( cause I'm not too bright ) why a pro digital camera's faster processing chip does so much better than something like my Nikon d800, re: rolling shutter... cause to ME a shutter speed is a shutter speed...but I'm not a scientist.

[excited_Genie16B8]

ANY and all advice would be much appreciated

Invent a Time Machine and go back about half a dozen years to wage an effective campaign convincing the masses to reject single chip CMOS cameras over the technologically superior 3 chip CCD's.

(While you're at it, could you also please kill MP3 and Napster, which are largely responsible for the failure of 5.1 music production replacing stereo as the norm.)

[jonathanwillis]

Just created an account to upvote this 🙂

[jane-e]

Just created an account to upvote this 🙂

By @jonathanwillis

To upvote, scroll to the top of the page and click the button on the far left of the subject.

[Stan Jones]

If that's the best you can do, and the other posts suggest it may be, then just enjoy. Very cool experience!

[rodneyb56060189]

Yeah, it is a cool looking plane and musta been fun flying in !

re: processing speed, my brain sorta sees it like these electrons getting sent out from chip in a sort of strange process that almost looks like a scan from the top down. So by the time the whole chip gets its electron info into processing circuits to create image something at the top already MOVED... so you get that curvy stuff.

duh, someday I hope to understand it better.

[Ann Bens]

It has nothing to do with framerate or exposure or whatever, it the type of censor: cmos.

CMOS Rolling Shutter

Dont think you can call a gopro a pro cam.

[rodneyb56060189]

Anne, Arri Alexa and Red camera and Panavision cameras are also cmos.

faster processing.

[rodneyb56060189]

ARRI Group: ALEXA´s Sensor

[rodneyb56060189]

Anne, I was saying the 'difference ' between the sensors is the processing speed... but to be honest I don't understand the science so I'm a dope.

[rodneyb56060189]

Anyway, I think we are on same page, Anne.. and understand the basics enough. I have a hard time trying to help people FIX THINGS due to the processing speed of the sensor ( same type (cmos)) but reduce the artifacts of the slower processing speeds.

[mattworks.com]

Appreciate it, everyone. It’s unfortunate I can’t fix the footage in post, but yeah, the flight was incredible. We did aerobatics and I captured an hour of video from two angles —- will post a link the full length in this forum once I do a rough edit.

matt