1 Topic by Chas Tennis (edited by Chas Tennis 2014-06-08 02:19:59)

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There is a very large range of frame rates in the camera discussions, for example from 10-1,000 frames per second.  Some of the readers might not be familiar with high speed videography and estimating the most basic camera requirements for their sports.

FRAME RATE (SAMPLING RATE).  30fps is a slow sampling rate that might be adequate for locating players moving around in most sports but it cannot be used for rapid motions such as golf club swings, tennis strokes, baseball hits, throwing, etc because the sampling rate is too slow. 

Consider how far an object (soccer player, tennis racket, arm, etc.) moves between frames for a given frame rate.  We are considering the velocity to be across the frame in all cases. Picture a golfer with the swing viewed from the side.

DISTANCE MOVED = OBJECT VELOCITY / FRAME RATE

For a golf club head traveling 100 MPH or 44.7 m/sec and a camera frame rate of 240 fps:

DISTANCE MOVED = 44.7 m/s / 240fps

DISTANCE MOVED = 186 mm   (each frame time), you catch the club every 19 cm.

For 30fps

DISTANCE MOVED = 1.49 m, inadequate for any useful swing information


MOTION BLUR. Motion blur is determined by the object velocity and exposure time (called "Shutter Speed").  For stop action frame-by-frame examination minimal motion blur can be very important.  (Exactly the same as shutter speed for still photography.)

For a camera viewing an object traveling across the frame - picture the golfer with the swing viewed from the side - the motion blur is equal to:

MOTION BLUR = OBJECT VELOCITY X SHUTTER SPEED

For the same golf club head velocity of 44.7 m/s and a shutter speed of 1/10,000 sec then

MOTION BLUR = 44.7 m/s X 1/10,000 s

MOTION BLUR = 4.47 mm, 1/10,000s is adequate for seeing how the golf club head is oriented.

On the other hand, an exposure time of 1/1,000s results in a motion blur of 44.7 mm - about the size of the entire head of the golf club - too blurry. 

High speed video cameras that operate with AUTO exposure control have unknown exposure times.  The camera's AUTO control will also usually pick an exposure time that is too long resulting in unnecessary motion blur. However, often the available light would have allowed considerably shorter exposure times (faster shutter speeds).

If you want to do stop action frame-by-frame analysis of sports motions be sure to purchase a HSV camera with adequate frame rate and manual shutter speed control.

In June 2011, to my knowledge the Casio Ex FH100 is the only affordable high speed video camera currently available that offers full manual control of the shutter speed.   Speculation is that the FH100 may no longer be manufactured but it is still probably in stock. ……..right now………  I have no financial interest.  Recommend that you download the full user’s manuals when selecting among high speed video cameras.

Each sport motion has different object velocities such as players moving around a field or a golf club head striking a golf ball.  What spatial information (in centimeters, etc.) and what temporal information (in milliseconds, etc.?) are you after?  Best estimate to be refined as you go.... Is the high speed video camera capable of giving you that information with the given object velocities?  Step one is to calculate the DISTANCE TRAVELED BETWEEN FRAMES & MOTION BLUR.

Jello Effect. Another issue for cameras is the Jello Effect caused by recording different parts of the image at very slightly different times.  This effect can cause image distortions and might especially affect higher resolution cameras with many lines of detectors (it takes time to record & readout the additional lines).

Bending golf clubs, Reply #562 -

http://www.golfwrx.com/forums/topic/250 … try3187037

http://www.golfwrx.com/forums/topic/250 … e__st__540

Jello Effect measured for my Casio FH100 Camera -

http://vimeo.com/21529497
https://vimeo.com/29160003

Other sites

dpreview Casio Forum -

http://forums.dpreview.com/forums/forum.asp?forum=1015


Golf site with a long Casio camera thread -

http://www.golfwrx.com/forums/topic/250 … e__st__600

2 Reply by JohnC

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Hi Chas,
Thanks for some very useful information.
Can the Casio FH100 be used to stream live video via USB at high frame rate please?

Thanks,
John

3 Reply by Chas Tennis

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My interest has been in stop-action frame-by-frame analysis of tennis strokes.  All videos were taken in high speed at 240 fps.   I also view the strokes in slow motion.   
I am not familiar with applications of computer capture using high speed video cameras.  I look forward to seeing some of those applications described in the other threads. 

Casio Ex FH100

To my knowledge--   

No Real-Time Video Out -  The Casio FH100 records to a HCSD card and then afterward that card can be read by a computer.   I'm nearly certain that there is no live video output capability.   

Full User's Manual, starting page 141. No live video output modes are discussed. -

http://support.casio.com/manualfile.php … =001011013

EYE-Fi. The FH100 also has an Eye-Fi capability which I have not used. (pg 156 & 157 of the Casio User's manual)   I believe that Eye-Fi operates by recording to a special Eye-Fi SD card and then the camera seeks a computer that is set up to automatically and wirelessly download from the SD card.  I believe, but am not certain, that the card operates only after the recording is complete.

http://www.eye.fi/how-it-works/basics

Continuous Record. In addition, the camera has a high speed video 'continuous record' mode where it records but only saves, for example, the last two seconds.  Then, if some rapid event is going to occur, but the exact time is unknown, the camera will still catch it.  The camera video button is pressed once to start the recording and a second time after the event to end the recording.  I believe that the only start-stop video control is by the button and that there is no external trigger, but again I'm not certain.

4 Reply by JohnC

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Thanks Chas,

It looks like the EX-FH100 may have been replaced by the EX-ZR100.
As far as I can see, it has similar specs except it has a 12MP sensor rather than 10.1MP.
It looks like it has the same high speed modes (up to 224x64 @1000fps).
Also it seems to have the 1/40,000 shutter speed and manual shutter speed available.

Similar price to the EX-FH100 at about £250 through Amazon less £50 promotion from Casio.

Any thoughts?

JohnC

5 Reply by Chas Tennis (edited by Chas Tennis 2014-04-09 23:24:22)

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The ZR100 may have some improved video features, such as the important capability to focus while recording video, but any improvements are not in the area of high speed video.  In fact the exposure control for the ZR100 is only AUTO, a giant step backward for high speed video.  See the discussion in the first message regarding AUTO exposure control.

Check this point yourself by downloading the User's Manual for the ZR100.

Again, I don't know of another currently available, affordable, high speed video camera with manual shutter control other than the FH100.   If you have one please supply the link that clearly describes the manual exposure control for high speed video. 

What has happened, I believe, is that since the introduction of the breakthrough Casio Ex F1 in 2008 not enough buyers understand the importance of manual control of the shutter speed and consider only frames per second.  They buy a camera and the motion blur is much larger than it would have been with a camera with manual shutter speed control, maybe they are disappointed with high speed video in general.  Unfortunately, the cameras with the superior capabilities for high speed video don't sell as well as they should.   The next design loses capability in high speed video as has happened with the FH100 transition to the new ZR100.

Look at Reply #591 and watch the first video which compares the ZR100 and FH100, the pertinent information starts around 1:50 sec into the video.

http://www.golfwrx.com/forums/topic/250 … e__st__570

UPDATE - 4/9/2014 - Still no manual exposure control.  2012 comments.
http://www.mytpi.com/articles/technolog … ed_cameras

6 Reply by JohnC

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Thanks for the clarification and links. I've ordered a FH100. Can't wait to play smile

JohnC

7 Reply by Chas Tennis (edited by Chas Tennis 2013-09-25 18:43:54)

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The Casio Ex FH100 is a great camera!

There is one quirk which I don't fully understand. It can easily be worked around.  In full manual mode, "M" on the dial, you set the shutter speed and the "aperture" which is a ND filter.  For the shutter speed I usually use 1/10,000s. At this shutter speed if you leave the ISO setting on AUTO the videos will be too dark.   Simply set also the ISO manually to 800 for a sunny day.  After seeing the video adjust the ISO up or down to get the brightness that you want in the video.  Forget ISO AUTO for high speed videos and fast shutter speeds. 

http://forums.dpreview.com/forums/read. … e=37098733

I don't understand why the FH100 ISO AUTO does this. Speculating, maybe at the faster shutter speeds the camera has trouble computing the proper ISO using AUTO. ? Or it defaults to low ISO.  It is easy to avoid.

I have a very tight fitting case without padding, "Cute case", with a slot to hold a spare battery & SD card.  It will stuff into you pocket but just barely.  http://www.cutecamcase.com/casio_case.html

Rather than print the downloaded or CD copy of the 200 page User's Manual, I bought a paper copy, computer printed, from Casio support, for $10. 

Reply # 552 has a video on camera settings that would have saved me a lot of time.   But disregard what is said about 1/2000s shutter speed and if light allows always set it faster to reduce motion blur.
http://www.golfwrx.com/forums/topic/250 … e__st__540

Let us know how you do.

8 Reply by JohnC

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My Casio FH100 has arrived and I took my first archery videos last night.

I’m very pleased with the results; thanks Chas for your suggestions.

Thanks for the tip on ISO. I set it to 800 and it was too dark (not much sun in England at the moment). At the maximum, ISO3200, it came out very well. 

The only snag is that the ISO setting needs to be made each time the camera is turned on as it returns to Auto.

So, in summary, I used: Full manual setting (M); Frame Rate 240 fps; Shutter 1/10,000 sec; Aperture 3.2; ISO 3200.

JohnC

9 Reply by Chas Tennis (edited by Chas Tennis 2017-02-20 12:16:12)

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FH100 Settings. The FH100 can be set to save many settings including ISO.    MENU-REC-MEMORY (last) - ISO   In MEMORY pick what you want to have set when you turn on the camera next time.   Take care with this as, for example, you might not want the 10 sec trigger delay that you use for golf videos set the next time you grab the camera for stills.  I’m still reading the 202 page user's manual and finding good stuff for high speed video settings.

I have not used the high resolution continuous stills operation.  You can save 30 high resolution still frames taken as fast as 40fps.  I'm not sure of the fastest shutter speed and have not tested for the Jello Effect.

Update (2/23/2013) - Burst Mode & Jello Effect Stills Testing-  http://forums.dpreview.com/forums/post/39393614
For stills the Casio FH100 can also do 10 fps using a mechanical leaf shutter (slower than the 40 fps electronic shutter). There is less distortion because the camera uses a mechanical leaf shutter instead of a focal-plane mechanical shutter.

Some first thoughts on high speed imaging for archery:

Internet Search. Searched archery and FH100 or High Speed Video and found lots of Youtube examples.  YT applies video compression and you cannot do stop action frame-by-frame.  I use Vimeo for videos because Vimeo uploads the full video. You still cannot do stop action viewing on the Vimeo site.  But others can download the video for proper stop action frame-by-frame viewing__CORRECTION SEE BELOW

Details on compression & non-compression as used by Vimeo are described in these FAQ-

http://vimeo.com/help/faq#compression.

UPDATE (2/20/2017) -  Youtube Single Frame - use the " . " PERIOD keystroke and the " , " COMMA keystroke.

-------------------------------------------------------------
UPDATE 2/20/2017 - Vimeo has a stop-action single-frame capability viewing on line using the arrow keys.  When watching a Vimeo video on line you can do stop action single frame forward and backwards using the arrow keys.  Hold SHIFT KEY and use the RIGHT & LEFT arrows.

---------------------------------------------------------------------------

I had found another link, now misplaced, to an archery application in England that had very useful information for high speed videoing of archery (an archery club?).

Here’s an interesting discussion. 

http://paleoplanet69529.yuku.com/topic/ … foOcFstXng

General Framing. Frame to cover all the action and maybe a little more, +/- 5% on the sides, top & bottom.  If a video has anything interesting outside the frame that is missed and the event can be repeated, always repeat the event and video it again.  Erase the poorly framed video later.   

Along the Trajectory Viewpoint. Camera views along (parallel to) and on the line of the trajectory's line will show the arrow for some distance.  Use the longest FL lens setting, 240mm, and frame the archer tightly by moving back.  If you use a wide angle FL the arrow image will become too small as it moves away and you will lose it much sooner.  On the other hand, wide angle lens settings probably produce a more attractive video of the archer. 

Along the Trajectory Viewpoint for Incoming Arrows - Not for the Faint-of-Heart or Careless. You can also shoot just to the side of or even at expendable mirrors for videos of incoming arrows – perhaps for the first time.  But the camera has to be very well protected including from arrows ricocheting from the mirror. As a last protection the camera should view through a Lucite protective window (1/2”) and probably be in a heavy protective box.  The smaller the mirror the closer the camera must be…………..

Backgrounds. To see arrows pick your backgrounds carefully.  Woods in shadow are convenient backgrounds as I just found for tennis serves.  Black targets that contrast with the arrows, etc.

Daylight Illumination. For overcast I can shoot at 1/10,000s and ISO 3200 where 1/10,000s is very adequate for tennis strokes.  But in direct sunlight 1/40,000s should work also for larger apertures.  1/40,000s will catch the arrows with less motion blur as calculated earlier. 

LED Markers. I did some tests recently for markers using LEDs that are available very cheaply - “Throwies”.  The ones I tested had directional beams (light emitted into an 8°cone) and therefore I did not think they were suitable for markers for most athletic motions.  For your arrows they might be ideal.  You might attach one to your arrow pointing back and see what you get.  I don't think one of these coin-sized LED/Battery assemblies can be a safety problem but consider with due care.

Arrow velocity.  Velocity equals distance travel divided by the time between frames.  If known, use the arrow length in the video as a convenient scale.  Be aware of motion blur errors which can easily be made negligible.

Arrow Impacts. Use the frame rate and motion blur calculations in this thread along with arrow velocity to calculate whether you can expect interesting results.  Use 1,000fps and a very tight coverage of say, the popular apple target. Protect the camera from stray arrows and if necessary view through a window to protect the camera from splatter and don’t mount the apple on something that could deflect the arrow toward the camera. 

Jello Effect. Because of the very high velocity of the bow motion be aware of the Jello Effect discussed in this thread.   The top and bottom of the bow will be mirror images.  If not, suspect the Jello Effect.  Test for by rotating the camera 90 & 180 degrees and repeating the videos.

Attractive vs. Analytical Videos.  I have no opinion on this issue but I have read that minimizing motion blur might make display videos less attractive.  That is, some motion blur should be present for the most attractive display videos.   When your objective is for more attractive display videos, as opposed to frame-by-frame analysis, experiment with shutter speed to get the most attractive videos.  Slower shutter speeds also allow you to use a lower ISO number and reduce the noise introduced by the higher ISO numbers. If you are doing analytical work always minimize the motion blur.

10 Reply by JohnC

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Thanks for pointing out the memory option.

This led me to find that the Left and Right (L/R) controls can be allocated to one of several operations. So I’ve allocated ISO setting to it rather than set it in memory. 

My interest is mainly in coaching archery so mostly I’ll be looking at the release hand, bow hand and arrow contact with the bow.

Your points on videoing from behind will be very useful for watching the arrow flight when tuning.

Trying to examine the bow tips on release should be interesting.  They should reach the same forwards point together at the point when the arrow detaches from the bow string. I guess the Jello Effect will need to be considered with this.

JohnC

11 Reply by Chas Tennis (edited by Chas Tennis 2013-08-26 15:42:07)

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Outdoor Sunlight and Indoor Lighting Issues for High Speed Video

Anyone using high speed video indoors and outdoors will soon discover that direct sunlight and even overcast skies produce much greater illumination than indoor lighting.  Using faster shutter speeds to reduce motion blur becomes very difficult with indoor illumination.  Here is a comparison between direct sunlight illumination and an average illumination level recommended for indoor tennis courts.

I don’t often work with photometric quantities. Anyhow, here is how I estimate the magnitudes of illumination for direct sunlight and indoor lighting.

Sunlight. 100,000 lumens / square meter on earth’s surface.

     http://en.wikipedia.org/wiki/Sunlight

Indoor Tennis Court Lighting. ~ average about 100 foot-candles or 1,076 lumens/m²

     http://sportsbuilders.org/tennis/guidel … on_2M2.cfm link not working
Another link added 8/26/2013 -
http://www.sportsbuilders.org/tennis/Sprecher.pdf

[Conversion for 100 foot-candles to lumens/m² (this link allows conversions between several units for illumination).
http://www.unitconversion.org/unit_conv … on-ex.html
100 ft-candles = 1,076 lumens/m²]

Ratio of direct sunlight to typical indoor lighting:

     100,000 lumens/m² / 1,076 lumens /m² = 92X

That is, the illumination produced by direct outdoor sunlight is 92 times greater than an average illumination recommended for indoor tennis courts. 

            Estimate for Direct Sunlight / Indoor Illumination -- 100X

Experience with Casio FH100.  I have used the Casio FH100 outdoors in direct sunlight, outdoors in overcast conditions and indoors at tennis facilities. 

Sunlight & Shadow. Video with Shutter Speed 1/40,000s. To demonstrate the FH100’s light sensitivity, below is a link to a video taken in direct sunlight and shadow using the fastest exposure time of 1/40,000s. 

     http://vimeo.com/26480215

The grey deck is well exposed and even in the adjacent shadow, other items are clearly seen. 

Overcast Skies.  I usually use a shutter speed of 1/10,000s and get well exposed images using ISO 1600 or 3200.

Indoors at a Tennis Facility. An exposure time of 1/400s produces dark but useable video images. For tennis motions shot indoors with the Casio FH100, using slow shutter speeds such as 1/400s, it is not possible to avoid considerable motion blur. 1/400s is 100X longer than the 1/40,000 exposure time used in direct sunlight for the Vimeo video above - consistent with the above estimate of 92X.  These subjective comparisons are based on comparing the camera display brightnesses of two video images and, therefore, are not that accurate.   

Once again, I don’t use photometric units or do estimates very often so double check my results on your own before using or referencing. Please make corrections.

ADDED 8/3/11 - Site with Recommended Light Levels in various locations.   Consistent with the 100X rule-of-thumb above.

http://www.engineeringtoolbox.com/light … d_708.html

12 Reply by Chas Tennis (edited by Chas Tennis 2014-12-13 23:34:31)

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Jello Effect Measurements for the Casio Ex FH100 Camera

The Jello Effect discussed earlier in this thread, Reply #1, is a distortion of the image produced because differently lines of the video image are recorded and read out at different times.  For example, a line at the top of the frame might be recorded & read out at time, t, but a line at the bottom of the frame will be recorded & read out at a later time, t + delay.   (The shutter speed for a given pixel is unaffected.) This effect is caused by the operation of the camera sensor’s electronics.  The shutter operation that causes the Jello Effect is called a Rolling Shutter. Rolling Shutter operation is used in most/all CMOS cameras like the Casios and other affordable high speed video cameras.   

An example of the Jello Effect is a false bend in the image of a golf club that is moving very fast.  See reply #1.  I believe that the more lines of video or still pictures that are involved, the greater the Jello Effect is likely to be.  Therefore, be aware of the Jello Effect especially for still pictures and HD video pictures that have many pixels and lines to read out.

There is also another shutter type, called a Global Shutter, where the image is recorded, recording is stopped and then the lines are read out.  Global Shutters do not display the Jello Effect.

It is easy to search the internet for: 1) Jello Effect, 2) Rolling Shutter, 3) Global Shutter, 4) Youtube Jello Effect, and 5) Youtube Jello Effect + Camera Model to find lots of information and many videos on Youtube.  Often the model of camera can be listed and examples of videos and stills can be found for that model.

Still, it is difficult to find quantitative information on the magnitude of the effect for a given model of camera.  I have not found useful information for the Casio FH100.  The manufacturers do not quantify it in technical notes for you because it is not a plus to aid sales. It is another thing to worry about when deciding to purchase a high speed video camera.   

That being said for most athletic motions captured with better quality high speed video cameras the Jello Effect will probably be small or negligible.  I have not yet noticed JE in FH100 high speed tennis videos because the tennis racket velocity has not been high enough.

Test for Jello Effect.  If you place a rotating disc with a line across the disc in front of the camera so that the line fills the image from top to bottom you can easily measure the JE for your camera for a given frame rate, shutter speed, etc.. 

Here are three Casio FH100 Jello Effect measurements for very fast objects:

1) Rotating bar at 8-9 revolutions/sec, 240fps.

     http://vimeo.com/21529497

2) Rotating bar at 21 rev/sec, 240fps.

     http://vimeo.com/25242212

3) Extreme Jello Effect at 330 rev/sec, 240fps.

     https://vimeo.com/25224520

As discussed earlier and in referenced links, a golf club at 100 MPH rotates at about half the rate of the first video above - a small but noticeable effect with the Casio FH100.

UPDATE 4/12/2014 - AIPTEK Action HD camera, 60 fps, 720 p.  Cylinder rotates 8 rps. The bar is parallel to the cylinder side but it falsely appears to be at an angle because of the Jello Effect. 
http://www.avsforum.com/content/type/61/id/411815/width/500/height/700/flags/LL
https://vimeo.com/30281692

Casio FH100, 240 fps. Cylinder rotates 21 rps. The bar is parallel to the cylinder side but it falsely appears to be at an angle because of the Jello Effect.
https://i.vimeocdn.com/video/195103030_960.jpg
https://vimeo.com/29160003

UPDATE 10/9/2012-  Stills Taken in Burst Mode
Jello Effect Tests for still photographs using the Casio FH100 in 'Burst Mode'.  The FH100 in electronic mode will save up to 30 high-resolution stills taken at a rate up to 40 fps. In mechanical shutter burst mode it can record at a reduced rate up to 10 fps.  Click "Gallery Page" to get descriptions.
http://forums.dpreview.com/forums/post/39393614

13 Reply by sojahulk

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Does anybody has some experience with the Casio Exilim EX-F1? Is it possible to live capture in highspeed using kinovea and this particular cam?

14 Reply by feedback

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Hello Sojahulk,

It is posible to live capture in highspeed using Casio´s driver but you can´t do that whith kinovea (at least I don´t know how).

15 Reply by joan

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feedback wrote:

It is posible to live capture in highspeed using Casio´s driver

Really? Interesting! I assumed the casio would only record highspeed to its internal card.
Do you have more details? Is it a new firmware for the camera ? What is the output connexion ? What software allows this?