Look what happens on release !

Watch_Man

Active member
Taking some photo's of archery_mum at a training session tonight I captured the following image just after release. I found it interesting to see the difference in the string below the arrow. The string above the arrow seems hardly to move but below it is nearly invisible. This photograph is not retouched in any way.

 


grimsby archer

New member
Taking some photo's of archery_mum at a training session tonight I captured the following image just after release. I found it interesting to see the difference in the string below the arrow.
I feel this is very similar to my comments about string pattern immediately following release in the photos you published here recently. Welbeck was it?
 


Watch_Man

Active member
I feel this is very similar to my comments about string pattern immediately following release in the photos you published here recently. Welbeck was it?
Yes it reflects the pattern. I have a couple of images from tonight illustrating this (someone you know :) ) but what I was not aware of from the Welbeck photos was how the string seemed to remain above the nock point. It looked like the string went into the shape but as it travelled away from the archer. This seems to show that the bottom section accelerates much faster.


 


Watch_Man

Active member
Does that mean that the bottom cam is going faster than the top?

Very cool picture :)
Anna it is common across all bows I have photographed including recurve (see the photos I just added) I would like someone to explain why it happens as there must be a scientific explanation.
 


grimsby archer

New member
Yes it reflects the pattern. I have a couple of images from tonight illustrating this (someone you know :) ) but what I was not aware of from the Welbeck photos was how the string seemed to remain above the nock point. It looked like the string went into the shape but as it travelled away from the archer. This seems to show that the bottom section accelerates much faster.
Thats what I was jumping up and down and waving my arms about.
Your photos from Welbeck were the first time I had ever seen this and I feel that it HAS to be significant.
I can see a reason for it in that the arrow is positioned above the center of the string, that is to say there is more string below the arrow than above, so youd maybe expect a bigger resonance curve in the bottom part of the string.
I never expected the difference to be so huge though. Id always thought that the bottom limb or cam would pull the string down/forwards in a straight line, towing the arrow behind it. Now it looks like the middle of the bottom half of the string is actually being catapulted forward of the arrow and bottom limb.
We need more photos and some really clever physics guys. This could be the biggest breakthrough in archery since the bowstring.
 


renniks

New member
Anna it is common across all bows I have photographed including recurve (see the photos I just added) I would like someone to explain why it happens as there must be a scientific explanation.
20 odd years ago I worked on early generations of CCD cameras on my university placement at EEV, but I doubt the principles have changed much.
The image is scanned pixel by pixel e.g top left to bottom right and processed sequentially. So there is a time delay between the top and bottom of the image, which I had thought would have been negligble on your previous (excellent) photos.
Perhaps you could experiment with the camera turned through 90 degrees, or even upside down to see whether the effect in the first picture can be reproduced, or reversed with the top limb in advance.
 


Anna K

New member
Ironman
Anna it is common across all bows I have photographed including recurve (see the photos I just added) I would like someone to explain why it happens as there must be a scientific explanation.
That's really interesting that it is the same in the recurve too (not just limited to one specific bow). It definitely suggests that the bottom limb (or cam) is travelling faster than the top. Is it designed like that though or is this to do with the height of the nock. The arrow is very rarely (if ever?) going to be in the very centre of the string.
 


geoffretired

Supporter
Supporter
I can't explain it Watch_Man, but it does look as if the two halves of the string are curved but in opposite directions. That reminds me of a physics lesson on music and plucked strings. First harmonic has two parts like an S. Each half string length is half phase out from the other. To create the first harmonic you pluck the string at some point or other away from the mid point. Our arrows are away from the mid point too. That could all be very wrong, but it sounds good don't you think??
Seriously. That is a very unexpected result. Brilliant photos. I still want our club to buy one of those EX-F1's
 


Watch_Man

Active member
20 odd years ago I worked on early generations of CCD cameras on my university placement at EEV, but I doubt the principles have changed much.
The image is scanned pixel by pixel e.g top left to bottom right and processed sequentially. So there is a time delay between the top and bottom of the image, which I had thought would have been negligble on your previous (excellent) photos.
Perhaps you could experiment with the camera turned through 90 degrees, or even upside down to see whether the effect in the first picture can be reproduced, or reversed with the top limb in advance.
If the weather holds then I will try this tomorrow night :)
 


Flying Whale

New member
20 odd years ago I worked on early generations of CCD cameras on my university placement at EEV, but I doubt the principles have changed much.
The image is scanned pixel by pixel e.g top left to bottom right and processed sequentially. So there is a time delay between the top and bottom of the image, which I had thought would have been negligble on your previous (excellent) photos.
Perhaps you could experiment with the camera turned through 90 degrees, or even upside down to see whether the effect in the first picture can be reproduced, or reversed with the top limb in advance.

Sounds like a very simple experiment to try. I would go with upside down if possible.
 


Tony_zelah

New member
Ok guess work here. But could it be caused by the fact that arrows are not nocked in the exact center of the string. Mean the upper half is a fraction of a second slower to move because of the extra weight (arrow nocking point peep sight) it has to propel
 


Hidden Hippo

New member
My guess would be that it is caused by the fact that the peep sight adds weight to the string (not much, but it could be significant), as well as the nocking point not being completely central.
 


Sea of vapours

New member
Assuming it's not down to the CCD scanning suggested above...

Could this not be down to the effect of the tiller setting? i.e. if the tiller were set perfectly, perhaps the imbalance in the string movement would be removed? If that /were/ the case it would be a [rather complex] way of checking tiller setting.
 


JohnR

The American
Supporter
American Shoot
20 odd years ago I worked on early generations of CCD cameras on my university placement at EEV, but I doubt the principles have changed much.
The image is scanned pixel by pixel e.g top left to bottom right and processed sequentially. So there is a time delay between the top and bottom of the image, which I had thought would have been negligble on your previous (excellent) photos.
Perhaps you could experiment with the camera turned through 90 degrees, or even upside down to see whether the effect in the first picture can be reproduced, or reversed with the top limb in advance.
I agree. It's exactly the picture you'd expect to get using a slot shutter (my photography goes further back than 'early CCD'!). Before you get too excited about explaining the mechanics, first eliminate the camera effects by using it upside down.

John
 


renniks

New member
Looking again at the positions of the rear edges of the fletchings, I'm certain it's an image capture effect.
I'm now intrigued as to what other images you can come up with using the casio - an arrow seemingly compressed to 6" after release? the path of the nock clearly traced on a single image?
Have fun.
 


BorderBows

New member
Not being compound guys!

We can see that tiller working in the recurve. And the same should happening in the compounds.
Question....
When you buy cams, are they specifically top and bottom... If so, i presume that the bottom is a fraction bigger, so make up for the limbs being the same weight... It pulls in more string quicker, making up for the same weight in the limb?
 


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