Re: Re: looking for high speed camera for school experiments -
David Timerman
3 Posts
As far as I know, the Nikon J series will only take 2-3 second long high speed videos. There is no work around that I've ever found. I use the a Casio Elixim fh-25 which was a very affordable point and shoot with 20x optical zoom that could take unlimited length videos. I do not know if Casio still makes similar cameras but this one shoots at 120, 440, 1000 fps - although the resolution is quite poor and it is not nearly as sensitive to ambient light as the Nikon J4.
Re: Re: Re: looking for high speed camera for school experiments -
Scott McCullough
4 Posts
The Edgertronic camera boasts a global shutter (it takes the image for each frame all at once) and a frame rate up to 18,000 fps (but with a limited number of pixels).
Price is $6000, $7000 if you get the larger memory. That may be too expensive for a high school, but it is significantly less than most high speed cameras.
The inventor was a student of Edgerton at MIT. edgertronic.com.
Check out some initial motion videos I made with it. http://spas.cis.indwes.edu/scott-mccullough/high-speed-videos/
Re: looking for high speed camera for school experiments -
Paul Nord
29 Posts
Also: The Casio Ex F1 Pro was cool in it's day. Its greatest feature is that it allows for continuous shooting at the high frame rates. The last time I checked on eBay they were selling for about 2.5 times what they cost new.
JVC made the GC-PX100. It feature an iOS app for fast analysis of sports training clips. I'm not sure JVC continued development of this product.
Re: Re: looking for high speed camera for school experiments -
Charlie Cote
2 Posts
I agree on the nice camera options mentioned by everyone in this thread. There is another issue concerning these cameras that I have been struggling with over the years. How can I verify the frame rate (cameral speed calibration) before each video data collection run?
I want to use high speed video to measure the motion of mechanical control system components used in critical safety systems. a 2% error, or greater, of actual camera frame rate could cause a significant error in my measurement results.
Can anyone reply to suggest a good way to check the camera frame rate before and after a data collection run?
Re: Re: Re: Re: looking for high speed camera for school experiments -
Charlie Cote
2 Posts
Thanks for the reply Bill. You suggested, "Use a tuning fork. It has a known period and you can use a microphone to check the exact frequency of the one that you are using.".
I am confused about how I can apply your technique. Should I compare the frequency of the tuning fork with the frequency of the sound that the camera makes during a video collection sequence? or are you suggesting that I take a video of the tuning fork?
My camera of choice is a low cost Casio camera with an advertised 1000 fps. taking a video of the tuning fork would more than likely result in position aliasing and would not be a reliable method of checking the FPS calibration of the camera - if I understand the technique you are suggesting.
Re: Re: Re: Re: Re: looking for high speed camera for school experiments -
Bill Bradley
2 Posts
I was suggesting the audio to check the exact frequency of the tuning fork and a test video of it. I also use inexpensive Casio (EX-FC150) in my classes, and it will give reasonable measurements of a lower frequency tuning fork (middle C or lower). If you are measuring over reasonable number of frames you should be able to detect any rolling shutter issues, or variations in the frame timing. The Casio cameras do not seem to do what many of the lower-end cameras do, which is repeating frames when the camera's memory or processor bogs down. If there are any issues with the video not being exactly 1000fps, or periodic glitches due to memory or processor limitations, those should show up in graphing a single point, and looking at the phase differences between different points should show any rolling shutter issues.
