Cheapest way to capture golf swing impact?
Prof Wonmug
moment of impact of a golf club and the ball? I just want to capture
the moment of impact, not the whole swing.
If I've done the math correctly, I need a camera that can capture
about 50 frames/second. The speed of the club head for an average golf
swing is about 100 mph. That's about 147 feet/second or about 12
inches/second. If I want to get a frame about every 0.25 inches, that
comes out to be about 50 frames/second.
I only need a few frames before and after the actual impact, but it's
probably easier to have the camera running longer than that to avoid
difficult timing problems.
What would I need to be able to set up a camera that can take at least
50 frames per second for a few seconds?
What type of camera? I am really only interested in digital.
What type of start/stop mechanism?
I assume a standard tripod would work?
Anything else I need to know?
Deep Reset
"Prof Wonmug" <won...@e.mcc> wrote in message
news:rcgg05due51io589q...@4ax.com...
> What's the cheapest setup that I could get that would capture the
> moment of impact of a golf club and the ball? I just want to capture
> the moment of impact, not the whole swing.
>
> If I've done the math correctly, I need a camera that can capture
> about 50 frames/second. The speed of the club head for an average golf
> swing is about 100 mph. That's about 147 feet/second or about 12
> inches/second.
OK stop there. Read the last sentence.
@ 50fps, the head has moved 147/50, or nearly three feet.
Time to examine your arithmetic.
Pat
If Google is to be believed, there are 63,360 inches per mile.
Therefore, 100 miles per hour is 6,336,000 inches per hour.
Therefore, 105,600 inches per minute
Therefore 1760 inches per second.
Therefore at 50 fps, it would travel 35.2 inches per frame.
Just to see if this seems reasonable, a fastball is about 100mph. It
is pitched from about 60 feet. Therefore it travels 720 inches
(actually 726). At 1760 feet per second, it would be 4/10s of a
second. That seems about right.
I think the prof dropped a 0 and if off by an order of magnitude. He
need about 500 fps.
The only way to reasonable do that, with readily available equipment
is to leave the camera on "B"; get total darkness, and set your flash
to shoot repeatedly (strobe effect) and use the flash to pick up the
multiple images.
That would take some doing (like hitting the ball in complete
darkness) but it would be possible.
Rich
A film SLR. ZERO lag-time. It's easy to capture it even without a
motor drive.
At the bottom of the swing, it'll surprise you, the club will be bent
by a considerable amount if the driver is strong. At 1/1000th of a
second, the ball is a 3" long (approx) blur.
Prof Wonmug
Ooopps. I divided in stread of multiplying (by 12).
If I've done it right now, that means that to capture a frame about
every 0.25 inch of an object moving at 100 mph, I'd need a camera that
can take roughly 7,000 frames/second.
franklin
If wanting only single still-frame shots use any of the 46 models of
inexpensive high-quality Canon Powershot cameras that are supported by
CHDK.
http://chdk.wikia.com/wiki/Main_Page
When using CHDK's optimized motion-detection scripts most of the cameras
have a motion-detection response times of 120ms or less, some of them
responding as fast as 32ms from the moment of motion-detection to shutter
activation. Many of them are used to capture lightning strikes, the shutter
triggered by the lightning's pre-strike "step-leader" before the actual
full lightning strike. At 12 inches per second you only have to have the
golf-club's head enter the camera's field-of-view about 12 inches from the
ball to fire a CHDK camera by motion detection. That would be an 83ms
response reaction time before contacting the ball.
http://chdk.wikia.com/wiki/CameraFeatures
The motion detection routines in CHDK have been optimized since that chart
was originally created, so most of the cameras are faster than the slowest
reaction times listed. There still seems to be a 32-45ms fastest reaction
limit for some models. As far as I know, none will react faster than that.
Set up your shot so that the golf-club enters the field of view of the
camera at the appropriate distance from the ball so the shutter opens at
the moment of impact. This will of course require some experimentation and
some random-chance. With enough shots you'll get what you are after. You'd
have to do nothing but keep swinging at golf-balls, the camera is doing all
the work automatically. You'll get high-resolution still-frame shots and
not depend on low-resolution frames grabbed from a video stream.
Keep in mind too that some of these Powershot cameras also come with a
60fps 320x240 video mode in them, if you'd rather use your video method.
You can use CHDK's motion-detection feature to trigger the starting and
stopping of video-captures. There are also the Casio EX-F1 and EX-FH20
cameras that can do video frame-rates up to 1200 fps for motion studies,
but the faster the frame-rate the lower the resolution. The 1200 fps is at
a 336x90 frame size.
An even less expensive and more accurate option for moment-of-impact shots
would be to use a small bit of foil on the surface of the ball and make the
golf-club and ball into a contact switch with a couple lengths of wire. You
could use any camera that allows you to hold the shutter open with any
flash-unit that you might happen to have. Make the golf-ball tee conductive
or use a metal tee, connecting it to one length of wire. Use a small strip
of foil-tape on each ball, so that when the golf-ball is placed on the tee
it is making contact with the metal of the tee. If the club is
electrically-conductive all the way to the face of the club attach the
other wire to the club's shaft. If not, run the wire down to the face of
the club. Connect those two wires to the trigger-contacts of your
flash-unit. Set up camera and flash in low-lighting, like at dusk or in an
indoor practice area. Swing away with the camera's shutter momentarily held
open for each shot. At the moment of impact the all conducting surfaces
will make contact, the flash will fire creating a high-speed exposure. Most
electronic flash units have flash durations of 1/5,000 of a second or
shorter.
If you are looking for a relatively inexpensive digital camera that allows
you to hold the shutter open, the latest versions of CHDK software allow
you to have the shutter open as long as 2048 seconds (34+ minutes) on some
models of cameras. Use low ISO's to avoid excessive amp-glow artifacts in
your images for longer exposure durations. There is little to no amp-glow
on exposures of up to 2-3 minutes on most CHDK cameras when using the
lowest ISO settings. CHDK and all its scripts are free, the camera will be
your main cost.
There is also the lowest-cost option that many have used by hacking very
inexpensive (or even free) disposable digital cameras, bypassing their
internal flash units to trigger them externally. Search for any of the
"high speed flash photography" articles at instructables.com. Such as this
one http://www.instructables.com/id/High-Speed-Flash-Photography/ Note the
comments, where one person gets bags full of disposable cameras for free
from a widely known source.
Prof Wonmug
>What's the cheapest setup that I could get that would capture the
>moment of impact of a golf club and the ball? I just want to capture
>the moment of impact, not the whole swing.
>
>If I've done the math correctly, I need a camera that can capture
>about 50 frames/second. The speed of the club head for an average golf
>swing is about 100 mph. That's about 147 feet/second or about 12
>inches/second. If I want to get a frame about every 0.25 inches, that
>comes out to be about 50 frames/second.
Arithmetic error. I divided by 12 instead of multiplying by 12. (sigh)
I should have said: That's about 147 feet/second or about 1760
inches/second. If I want to get a frame about every 0.25 inches, that
comes out to be about 7.040 frames/second.
I just want to capture the exact moment of impact as close as
possible. Being off by as much as half an inch should be OK.
Is there a consumer video camera that can do that?
Prof Wonmug
wrote:
>On May 11, 11:53�am, Prof Wonmug <won...@e.mcc> wrote:
>> What's the cheapest setup that I could get that would capture the
>> moment of impact of a golf club and the ball? I just want to capture
>> the moment of impact, not the whole swing.
>>
>> If I've done the math correctly, I need a camera that can capture
>> about 50 frames/second. The speed of the club head for an average golf
>> swing is about 100 mph. That's about 147 feet/second or about 12
>> inches/second. If I want to get a frame about every 0.25 inches, that
>> comes out to be about 50 frames/second.
>>
>> I only need a few frames before and after the actual impact, but it's
>> probably easier to have the camera running longer than that to avoid
>> difficult timing problems.
>>
>> What would I need to be able to set up a camera that can take at least
>> 50 frames per second for a few seconds?
>>
>> What type of camera? I am really only interested in digital.
>>
>> What type of start/stop mechanism?
>>
>> I assume a standard tripod would work?
>>
>> Anything else I need to know?
>
>A film SLR. ZERO lag-time. It's easy to capture it even without a
>motor drive.
How? How do I get the camera to take the photo sometime between actual
impact and about half an inch later?
At 100 mph, it only takes 0.000568 seconds to travel one inch. That's
my window. Actually, I'd like to get it to half that.
>At the bottom of the swing, it'll surprise you, the club will be bent
>by a considerable amount if the driver is strong. At 1/1000th of a
>second, the ball is a 3" long (approx) blur.
I don't care how long the blur is as long as I can tell exactly where
on the club face the ball make impact.
Deep Reset
"Prof Wonmug" <won...@e.mcc> wrote in message
No.
Casio EX-FH20 claims about 1000 fps.
Probably needs lots of light too.
If all you want to do is capture the strike, why do you need a video camera?
Does it have to be outside?
Fairly simple triggers could be setup in a darkened room and even an
inexpensive flash should be able to manage 1/30000th of a second.
Or, as has been pointed out, have a look at CHDK for Canon.
Pat
Depending on your definition of "cheap", this would work:
http://www.bhphotovideo.com/c/product/554003-REG/For_A_VFC_1000SB_VFC_1000SB_High_Speed_Variable.html
The ultimate in cheap might be going to a stock image agency and
buying an image that already exists.
You might call around to some testing labs and see what they have
available and if they can do it for you.
Otherwise, I think you'll be stuck with a strobe
tony cooper
Not really. You need any camera and lots of patience.
--
Tony Cooper - Orlando, Florida
Savageduck
Take a look at this, they even mention frame rate adjustment to analyze
golf swing.
"Smooth Slow Record:
The Smooth Slow Record mode increases the record rate from 60 frames
per second (fps) to 240 fps, allowing you to capture 3 seconds of fast
motion and play the video back in 12 seconds. This is a great tool for
analyzing a golf swing or a viewing a bird in flight. In addition, you
record an audio track to narrate the video footage."
Regards,
Savageduck
Nicko
> What's the cheapest setup that I could get that would capture the
> moment of impact of a golf club and the ball? I just want to capture
> the moment of impact, not the whole swing.
Put your head between the ball and the club.
If the golfer swings just hard enough, maybe the moment of impact will
be preserved in your brain.
--
YOP...
John McWilliams
Coat the club face with flour. Then you can tell the exact coordinates
of the point of impact.
--
john mcwilliams
Wally
Set up a manual flash with trigger contacts where the shaft of the
club will hit it just before impact with the ball. Then in near
darkness open shutter and swing club. The flash will capture the
action. Move the contacts back and forth to fine tune the timing.
Wally
Bob Williams
Use any convenient camera that has a shutter speed of say 2 seconds and
a f-stop of preferably 11 or more.
Keep the ambient lighting as low as needed to see the ball comfortably.
Set up an electronic flash unit with a PC cord a few inches away from
the ball.
Connect two bare wires (about 1-2 mm apart) to the PC connector.
Place one of the two bare wires in contact with the back of the ball
(the non-struck surface).
At the start of the swing, trip the camera shutter.
When the ball moves 1mm forward the two bare wires will make contact and
trigger the electronic flash.
Most consumer flash units can produce flash durations of 1/10,000
second. That should be fat enough for your purposes.
At small apertures in low light situations ambient light will contribute
practically nothing to the exposure.
You probably have all the stuff you need at home already.
Bob Williams.
whisky-dave
"Prof Wonmug" <won...@e.mcc> wrote in message
> On Mon, 11 May 2009 11:42:36 -0700 (PDT), Rich <rande...@gmail.com>
> wrote:
>
>>On May 11, 11:53 am, Prof Wonmug <won...@e.mcc> wrote:
>>> What's the cheapest setup that I could get that would capture the
>>> moment of impact of a golf club and the ball? I just want to capture
>>> the moment of impact, not the whole swing.
>>>
>>> If I've done the math correctly, I need a camera that can capture
>>> about 50 frames/second. The speed of the club head for an average golf
>>> swing is about 100 mph. That's about 147 feet/second or about 12
>>> inches/second. If I want to get a frame about every 0.25 inches, that
>>> comes out to be about 50 frames/second.
>>>
>>> I only need a few frames before and after the actual impact, but it's
>>> probably easier to have the camera running longer than that to avoid
>>> difficult timing problems.
>>>
>>> What would I need to be able to set up a camera that can take at least
>>> 50 frames per second for a few seconds?
>>>
>>> What type of camera? I am really only interested in digital.
>>>
>>> What type of start/stop mechanism?
>>>
>>> I assume a standard tripod would work?
>>>
>>> Anything else I need to know?
>>
>>A film SLR. ZERO lag-time. It's easy to capture it even without a
>>motor drive.
>
> How? How do I get the camera to take the photo sometime between actual
> impact and about half an inch later?
Trigger the flash by sound or use a sensor where the ball cuts a beam which
triggers
the flash or perhaps even the shutter.
> At 100 mph, it only takes 0.000568 seconds to travel one inch. That's
> my window. Actually, I'd like to get it to half that.
No problem, lots of things have been photographed that travel faster ;)
>>At the bottom of the swing, it'll surprise you, the club will be bent
>>by a considerable amount if the driver is strong. At 1/1000th of a
>>second, the ball is a 3" long (approx) blur.
>
> I don't care how long the blur is as long as I can tell exactly where
> on the club face the ball make impact.
why not just cover the bal in some sort of ink/paint that will come off the
ball when hit.
BTW what is the actual aim of this project ?
Prof Wonmug
Will flour actually work? Wet or dry?
It turns out that they do sell tape or stickers for the club face that
will show where the ball made contact.
Prof Wonmug
That sounds more technical that I am up for...
>> At 100 mph, it only takes 0.000568 seconds to travel one inch. That's
>> my window. Actually, I'd like to get it to half that.
>
>No problem, lots of things have been photographed that travel faster ;)
Of course, but at what cost?
>>>At the bottom of the swing, it'll surprise you, the club will be bent
>>>by a considerable amount if the driver is strong. At 1/1000th of a
>>>second, the ball is a 3" long (approx) blur.
>>
>> I don't care how long the blur is as long as I can tell exactly where
>> on the club face the ball make impact.
>
>why not just cover the bal in some sort of ink/paint that will come off the
>ball when hit.
Interesting idea. A little messy...
>BTW what is the actual aim of this project ?
To lern where the ball makes contact so as to improve my swing.
Prof Wonmug
wrote:
Wow. I had no idea all of this programmability existed. Thanks for the
pointers. Lot of reading to do...
John McWilliams
Yes, and you could make your own stickers if you wished.
I'd try the flour dry, but most likely it won't cover enough. So, wet
the club face, then sift a small layer on.
--
john mcwilliams
Chris Malcolm
Candle soot is easier and more indicative. Apply from halfway down the
flame as in smoking glass.
--
Chris Malcolm
Prof Wonmug
<jp...@comcast.net> wrote:
I couldn't get the flour to work and it was very messy. It turns out
that there are better ways. Dry erase markers work very well. They can
be applied to the club face or the ball, but I found it worked better
on the club. Various types of tape also work pretty well. Duct tape
worked best for me.
John McWilliams
Glad it got you started, away from the photo bit, which would've given
you only one axis, unless in front of the club face!
--
john mcwilliams