My Gopro 3+ Black 180 degree stereo rig

Those of you using dual go pros: Did you try clapping your hands once right after pressing the record button to sync video in postproduction without having to use sync cables ? I'd like to know whether that method works at all, or if the final result feels a bit off.
Thank you.

"HD148478" wrote:
Those of you using dual go pros: Did you try clapping your hands once right after pressing the record button to sync video in postproduction without having to use sync cables ? I'd like to know whether that method works at all, or if the final result feels a bit off.
Thank you.

Clap or any sort of visual signal will give you frame-level sync at best. With a potential for a half frame interval discrepancy between the eyes.

One thing that has helped me better understand the (long) list of gotchas of VR is the Oculus World demo in debug mode where you can toggle off timewarp, prediction, vsync, etc. It is invaluable to really grasp the difference between an experience that is very slightly off, and the correct one.

I think we would need some sort of similar demo for video content. Something where we can better visualize the impact of mis-sync, IPD mismatch, loss of stereo, retinal rivalry, etc. If we could have a demo with a reference content with various instances of these subtle defects it would help "recognition".

I see, thanks for your feedback. It's amazing that half a frame can have such a negative impact. I thought you could press record with the wi-fi remote and be more or less safe... because many people emphasize that there are DIY solutions for 30 dollars or so, but if you don't use cables I guess that's not good enough.

"HD148478" wrote:
I see, thanks for your feedback. It's amazing that half a frame can have such a negative impact. I thought you could press record with the wi-fi remote and be more or less safe... because many people emphasize that there are DIY solutions for 30 dollars or so, but if you don't use cables I guess that's not good enough.

The Wifi Remote is worse than post-syncing with a sound spike or flash generally. Wifi Remote syncing might be as much as two or three frames off. Sound or flash syncing gets you to within half a frame as has been explained but it gets tired real quick doing it for every pair of movies and half a frame is a much worse for 3d syncing than for 2d syncing (like for 2D 360 camera arrays). The reason being that for 3d video/stills the missync may be interpreted by the brain as a depth distortion as well as a retinal rivalry phenomenon.

A fast car whizzing by on the street in the background of a shot might appear to be towards or away from you in space as often the brain interprets the lateral visual movement as parallax. You really need very perfect sync -- like to within a couple of milleseconds to be confident your 3d shots will be usable with fast subjects.

And with the Dual Hero System for Gopro 3+ Black Gopro actually developed a very sophisticated sync solution for the price -- even though very few people probably use it.

As Mewpro says: "As stated in our previous post, 3D video/photo captures by GoPro are very strict and accurate: They require genlock signals of not only VSYNC for every frame but also HSYNC for every scanning line"
http://mewpro.cc/2015/02/06/genlocking-with-mewpro/

If they do update the Gopro 4 firmware to use the Dual Hero System, and Mewpro's solution for multiple Gopro syncing works it will be a breakthrough for a number of what have been high end multi camera sync concepts -- eg. close camera arrays for "frozen moment" shots and autostereoscopic multiview videography and lenticular postcard production, as well as virtual reality video and still photography applications. (And sometime Gopro might implement multicamera syncing itself -- there have been the odd rumor -- it would give them good publicity type shots)

Mewpro aka Orangkucing Lab has posted four videos taken with his multi-Gopro genlock dongles (4 cameras).
http://mewpro.cc/2015/03/18/sample-vide ... ck-dongle/

(for Gopro 3+ Black plus Dual Hero System)

he says he will post prices etc soon

I downloaded the videos and checked the sync via video and audio in After Effects and it seems excellent -- much better than you would get from post sync -- ie. the sync is accurate audio-wise at least to less than 1/20th of a frame I would say.

[edit] now he has prices -- if I understand it correctly for say 3 cameras, you would need one Dongle ($50) and two Mewpro Gopro backs ($100 assembled each) -- plus you need the Dual Hero System. He says each camera can be connected by a cable up to at least 30 cm long -- which gives a lot more scope for hyperstereoscopy than previously. You also need an external usb power supply to power the dongle via the Master camera usb input.

I have not seen side by side comparison between the iZugar lenses and the iLiExpress but the results from both are very good.
I have the iZugar lenses but currently not using them with GoPro, The image quality is extremely good.

Are you using the iZugar 185° or 220°?

I have 6 of the ~182° lenses from iZugar.
Just got two GoProHero4Black Doing a burn in test to make sure they are ok before swapping out the lenses.

I have 6 of the ~182° lenses from iZugar.
Just got two GoProHero4Black Doing a burn in test to make sure they are ok before swapping out the lenses.

I've been using 12 GoPros in custom rigs and the stitching/exposure blending is a pain. I'm going to switch to the fisheye mod approach. I want more than 180, but I don't want to fall down the perfect-360-3D rabbit hole. I can't wait to see what you come up with using the GoPros!

What kind of coating do the iZugar lenses have? Any issues with flare?

I'm looking for a cheap stereo action cam setup.

So far, I found the KeeCoo ~$60 (with 170 degree wide angle lens) and the SJ4000/5000/5000+ etc (also with 170 degree wide angle lens).

Both cams support M12 super wide angle lens, e.g. the ones mentioned in this thread.

Finally, there is also the new Xiaomi Yi ~$80, which only has 155 degree angle lens.

Does anyone have experience with one of the above cams?

It could really be a cheap stereo solution for VR.

GoProHero3Black with sync cable will give you proper sync.
Without proper sync need to shoot 60fps and will want to keep the camera stationary.