Wednesday, August 23, 2017

Eclipse results

After my last post, here is the follow up with the results

 Eclipse 2017 Edit from David Newman on Vimeo.

One thing I wish I did, was set an additional camera for video with a locked exposure.  The light levels changed fast when approaching the totality, too fast for long interval time-lapse to deliver the real-time experience.  Also the auto exposure of the TLV and night-lapsing cameras reduced the drama of the lighting change, so a locked camera would solve both issues.  I used four GoPro cameras for the above video, next time I will use five or more.

Friday, August 18, 2017

Shooting the Eclipse 2017 with a GoPro

I'm planning to find my way into the path of totality, and be there with a bunch of GoPro gear. I've been asked many times how to shoot this event with a GoPro, so here are my thoughts. Disclaimer: this is my completely unpracticed opinion on shooting a total solar eclipse with a GoPro.

Some basics. The whole transit from start to finish, somewhat depending on your location, is about 3 hours. That is pushing the average GoPro a little beyond its battery life in a time-lapse mode, even more beyond in regular video mode. As three hours likely produces pretty boring video, time-lapse is the way to go. If you intend to time-lapse the entire transit, you can use any USB power brick to extend the GoPro's run time; I've done a week long time-lapse via USB power. If you intend to shoot on battery power alone, on a full charge I typically get about 2 to 2.5 hours of time-lapse on a HERO5 Black with a 5-10 second interval.  Plan to start your time-lapse about 1 hour before totality.

Timing. Time-lapse interval for two hour capture, my best estimate is 5 seconds. Which will be a 48 second video when played at 30p.  A shorter video to share would be better, yet if you are lucky to have two minutes of totality, this interval only gets you 24 frames (0.8s) of time in the totality.  If you intend to work on the video with a speed ramp for the less exciting bits, then a 1 or 2 second interval might be better, but watch out for your battery life.

Framing.  As you know the GoPro lens is very wide, forget about getting any close-up views -- well without mounting the GoPro against an eyepiece of a telescope, which I will be doing in one setup.

Practicing: A video frame extracted from GoPro through the eyepiece of a sub-$200 4" telescope with a solar filter.  
With a wide time-lapse, consider how the light will change across the landscape, so compose your framing to capture that.

Filters. A GoPro will not be shooting through those safety filters, those are for your eyes and telescopes etc. Using a solar filter on a GoPro will give you a very small orange dot that moves across the frame, if you are lucky -- don't do this.  If you have ND filters, you can use them or not, modern GoPros are used to shooting images that also contain the sun, the sun's image is too small on the sensor to do damage.

Exposure control. In most cases a GoPro is an auto exposing camera, this is a good thing for those in the path of totality as the camera will adjust for all lighting conditions, give you a good video throughout. The downside for those not in the path of totality the auto-exposure will reduce dramatic level of changing light level. On a Hero 4 Silver and on HERO 4/5 Black, you can lock the ISO to 100 and set a fixed shutter speed, but only in the video modes with Protune enabled, so you will be left to process a lot of video into a timelapse in post.  You will also need ND16 or ND32 filters to make locking the exposure work for a correctly exposed image at the beginning of you capture.

Time-lapse video vs time-lapse photo vs Night-Lapse photo. Time-lapse video (TLV) is the easiest by far, producing a small MP4 that is ready to share, as soon as the cell service recovers from the network load of millions of eclipse chasers filling small country towns. The downside of TLV is there are no Protune controls, it is all automatic. The other two time-lapse modes will produce JPGs (and GPRs if RAW is enabled) and you can have Protune level controls to set the look (GoPro vs Flat), white balance, ISO, sharpness etc.  If you are in the path of totality, choose Night-Lapse, it will still work during daylight, but will take much longer exposures as needed for the dark few minutes.

My Recommendations: For those willing to do color correction and post assemble a time-lapse: Night-Lapse, Auto shutter, 4 second interval, Protune Flat, Native White balance (or 5500K for simpler color correction), ISO Min 100, ISO Max 800.  I will enable RAW.  This will produce 1800 images over 2 hours, one set of JPGs and one set of GPRs, using about 18 GB for storage.  If you want a fast easy time-lapse, use Time-lapse video with a 5 second interval.