Annoying curvature lines

[Larry Secrest]

Hello,

On many of the footage I see online I'm noticing a lot of curvature lines from the footage of the GoPro Hero4, Silver and Black. Recently somebody made a movie called Tangerine, with three Iphones. That made me though that the GoPro cams could be at least as good if not better than iphones. But I simply can't get over these curvature lines. I'm wondering if the GoPro can be used for fiction?

What does anybody think here?
Thanks

[Mark Rosenzweig]

Originally Posted by Larry Secrest

Hello,

On many of the footage I see online I'm noticing a lot of curvature lines from the footage of the GoPro Hero4, Silver and Black. Recently somebody made a movie called Tangerine, with three Iphones. That made me though that the GoPro cams could be at least as good if not better than iphones. But I simply can't get over these curvature lines. I'm wondering if the GoPro can be used for fiction?

What does anybody think here?
Thanks

Here are some tips:

1. In shooting 4K, you can while shooting minimize curvature by avoiding straight-line objects and people at the edges *or* you can correct curvature in post (the GoPro software has a plug-in specifically for this). You can also use curvature (sparingly) purposely for creative effects. Fish-eye is a look.

2. In shooting 2.7K, you can choose 'Medium' POV (there is no choice of POV for 4K), which has minimal curvature.

Both resolutions are better than the iPhone, and you can even shoot 2.7K at 60fps for smooth motion or slo-mo. Or 24P if you want a film look for either resolution.

[Larry Secrest]

Thanks Mark.
Avoiding straight-line objects is not really an option though.

[Mark Rosenzweig]

Originally Posted by Larry Secrest

Thanks Mark.
Avoiding straight-line objects is not really an option though.

Of course, but the point is to watch them *at the edge of the frame*. A lamp post will be perfectly straight at the center of the frame, but will be quite bent at the edge. So you watch carefully what you frame. Similarly for vista shots - if the horizon is in the middle it will be perfectly straight, but near the top or bottom of the frame it will be bent. So, you can minimize the distortion (and still shoot straight-line objects) by judicial framing.

Here is a 4K video shot without any correction, but with judicious framing to minimize curvature:

GoPro Hero 4 Black 4K Video: A Stormy Day at Palm Beach on Vimeo

[Nate Haustein]

Have you thought about modifying your Hero4 with an aftermarket rectilinear CCTV lens? Did mine for about $100. It's pretty sweet. No more curvy lamp posts.

[Charles W. Hull]

Originally Posted by Nate Haustein

Have you thought about modifying your Hero4 with an aftermarket rectilinear CCTV lens? Did mine for about $100. It's pretty sweet. No more curvy lamp posts.

I did that, and found the image quality was maybe good enough for HD, but not for 4K. I went back to the normal GoPro lens.

[Nate Haustein]

Charles, which lens did you try out? The 5.4mm looks very sharp to my eye in 4k.

[John C. Chu]

How about fixing it in software?
This plugin looks intriguing.

Fisheye Fixer for GoPro® - Fisheye Correction FCPX plugin | CrumplePop

And this free one for FCPX:
http://alex4d.com/7-alex4d-wide-angle-fix-effect

I didn't realize GoPro also software in to fix it. Might have to look at one of these cameras.

[Charles W. Hull]

Originally Posted by Nate Haustein

Charles, which lens did you try out? The 5.4mm looks very sharp to my eye in 4k.

Glad to hear that. Yes, I tried the 5.4mm, and it was sharp in the center, but the sharpness dropped off drastically toward the both sides. Perhaps there is lens to lens variation, or maybe I had a poor installation. I had high hopes for 4K video, and if people continue to report good results I may try again in a year or so.