What do you use to record

[Chris Taylor]

What device do you use or feel is best to record your sets with a wakeye or ski doc? Cell phone, GoPro or other sports cam, Camera?

[Horton]

Samsung Galaxy S5. Works great.

[lcgordon]

Iphone in the spotters hands and sometimes a gopro

[thager]

IPAD.

[mikegile]

iPhone

[DefectiveDave]

Wakeye with a custom built isolator platform. I use a JVC camcorder (GZ-HM650BUS I think) with image stabilization that works well at higher frequencies in case the isolator platform misses something.

 

I think it works pretty well, here's a sample video:

 

[david_ski]

@DefectiveDave show us a picture of your custom made isolation adapter for the wakeye

[ktm300]

I like the ease of using my phone to record. However, it does not have a manual focus mode so is always hunting for focus. Video watched in real speed is acceptable. In slo mo, it seems every other frame is way out of focus. I don't and won't own Apple. What is a good remedy to get solid focus on the skier? Any phones have manual focus for video or auto focus that steadily keeps the skier in focus?

[Waternut]

I'll second @DefectiveDave. I really like the JVC cameras. I had the JVC HM650BU and just changed to the EX210BU which is basically the same thing. The original JVC was good but after 2-3 years, it was starting to get a little glitchy and shut down on hot days. I use a standard Trakker mount and the rattling you hear turned out to be a loose screw/spring in the mount and nothing to do with the camera.

 

[DefectiveDave]

@david_ski,

 

As @Waternut said, the JVC camcorders probably get you 70-80% the way there (I've tried sony, canon, and panasonic with really ugly results due to pylon vibration). In fact, in his video it looks like it is working really well. I might try the camcorder first and see if the quality is acceptable before making an isolator.

 

It might be that my pylon has more vibration than normal, but I was still seeing some significant vibration even with the JVC until I added the isolator. Here are some pictures of what I built for reference, it is very basic.

 

 

- 3/16" wire rope is used to isolate the top platform from the bottom where it is attached to the wakeye.

 

 

- Blocks at the back stabilize the camera.

 

 

- A go-pro mount at the bottom is what is used to attach the wakeye.

 

I designed it such that it reduces the transmissibility of anything above about 8 Hz when a 300 gram camcorder is attached to the top plate. Otherwise the wire ropes started getting too long and the tracking would start to lag behind the skier. My final wire rope lengths were 3-inches at each corner.

 

If you want to use different wire ropes, a camera of a different weight, or isolate for different frequencies then you'll need to make some adjustments. My design only took 3 steps:

 

1) Identify the maximum shear stiffness in a lateral direction. This turned out to be very linear in my measurements and corresponded to the starboard-port and bow-stern directions when the camera is facing directly behind the boat.

 

2) Determine total mass of top plate. Use this and the stiffness to determine your approximate natural frequency.

 

3) Use the transmissibility relationship (https://en.wikipedia.org/wiki/Damping) to ensure that you isolate for anything above a given frequency to below a given transmissibility threshold. Assume the damping coefficient is 0 and I suggest trying to reduce transmissibility of any vibrations above 10 Hz, because this is the treshold above which the image stabilization methods on most cameras stop working effectively.

 

Good luck!

[Waternut]

Well I haven't really had a problem with vibration with a 2000 ski nautique. In fact, the video above is with the stabilization off. When I turn the stabilization on, I struggle with keeping the skier in the picture because the shock tube really interferes with how well the Trakker mount works.

 

However, I will say that handle pops do a heck of a number on the camera and I'm guessing that's why the first camera started acting up. This is also why I don't mount my $400-$600 cell phone on the pylon...

[gregy]

@waternut my trakker makes the same vibration noise. What was the problem?

[ozski]

Galaxy s4 with wake eye app, its better than good enough.

[LZywicki1]

SkiDoc ppylon mount, Samsung phone and the wake app., without any zoom.

Video is 32.4 @15 off.

 

[Waternut]

@gregy I removed the spring loaded button that helps prevent the camera mount from falling out if you forget to tighten it. I also ground off the tab on the thumb lever that prevents over tightening the mount so that I could over tighten it. Then just make sure the camera tightening screw is tight.

[david_ski]

@DefectiveDave Thanks for the pics and the link. The wake eye mount and smart phones are the desired end goal. Each skiers video is on their own personal device. No need to have one person doing video editing each day and distributing USB flash drives back and forth. Cloud storage for massive numbers of videos is not free. Resorting to video camera is the backup alternative. We have tried GoPro, Liquid Image, and the Sony Action Cam this summer all with disappointing results. Smart phones deliver exceptional video when hand held. Goal is to modify a pylon mount to be almost vibration free. We get similar results from the wakeye mount on different boats so it is not a particular boat issue.

 

It has been a long time since I played with diff equations. I will get my son to work the math. I want to work on an isolator for the phone attachment mount. GoPro mounts on top and bottom. I will probably need to add some mass to the top plate to make this concept work with a smart phone. I might make it out of HDPE to eliminate any wood and add some mass.

[DefectiveDave]

@david_ski,

 

A smart phone mount would definitely be possible. However, as you have suspected, you will probably need to add a little bit of extra mass in order to bring the natural frequency down. No Diff. Eq. is necessary, just use the transmissibility envelope for zero damping here:

 

https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Resonance.PNG/1920px-Resonance.PNG

 

Also, you can approximate the natural frequency using the relationship here:

 

https://en.wikipedia.org/wiki/Fundamental_frequency

 

Just be aware that the natural frequency equation in the above wikipedia page gives you the frequency in Hz, so make sure you don't use radians for your target frequency in the transmissibility envelope. Good luck!

[david_ski]

@DefectiveDave Great info, thanks. I picked up some 3/16 wire rope at neighborhood big box store. I have a couple of pieces of HDPE blocks. It is time to start tinkering around in the shop.

 

Today the rain for winter season started and the ski window is going to close shut pretty soon. Only problem is that with rain starting and lake closing down for winter, it will be hard to test and tweak the setup.

[disland]

iPhone 4S with Wakeye, Interestingly the 4S worked but the 4 didnt