Sound Trigger - where to go and what to get

Wow that Camera Axe looks fun!

I was trying to work out how they did the real high speed stuff with a normal camera... then found some sample pics with the EXIF in them - they are doing a long exposure shot (5 seconds it seems) of a dimly lit scene and triggering a flash, not the camera, with the Camera Axe. The flash fully illuminates the scene rather than just fill and of course the duration of the effective exposure is down to the duration of the flash pulse - which can be very quick indeed, much quicker than your camera shutter can achieve.

Doing a little more reading about flash pulse duration, it seems the lower the power, the shorter the duration - I suppose that makes sense, I guess I've just never had to think about it before!

It seems the trick is to place the flash 7 to 10 inches (about 18 to 25 cm), ISO 200 and f/16 and about 5 seconds of exposure. Trigger the camera then do your whatever.

On the question of camera kit, the camera doesn't seem to matter too much, as long as it can give a long exposure - I guess you could always use bulb if 5 seconds wasn't available.

The flash kit does seem to matter though as the flash duration is the key to really high shutter speeds

The SB600 will only give you 1/25000 sec. at M 1/64 output whereas the SB900 will give you 1/38500 sec. at M1/128 output - ironically the older SB800 will do 1/41600 sec. at M 1/128 output.

It seems the winner here in the high speed game is a SB800!

BTW, just for comparison, my D300 shutter will only do 1/8000 and then add some shutter lag thats way disproportionate in this game - so you can see how the flash is the way to do it!
 
The "Axe" has two independant outputs to trigger devices so you can set the shutter for say half a second (avoids the need to have too dark an environment) and get the flsh to fire in the middle of the shutter open time.

Bob
 
Bob

Thanks so much for this. I've been looking at some motion sensor stuff for wildlife traps and the Mumford Time Machine is just too expensive. I'd been considering a full "homebrew" project but am a bit short of time at the moment. The kit of this stuff looks like a great compromise.

Thanks again, off to place an order...

Paul
 
Canon Bob said:
I use one of these http://www.cameraaxe.com/ .

It can be configured with a variety of input sensors and has timing delay control for occasions that need it.

HTH

Bob
Click to expand...

desantnik said:
Wow that Camera Axe looks fun!

I was trying to work out how they did the real high speed stuff with a normal camera... then found some sample pics with the EXIF in them - they are doing a long exposure shot (5 seconds it seems) of a dimly lit scene and triggering a flash, not the camera, with the Camera Axe. The flash fully illuminates the scene rather than just fill and of course the duration of the effective exposure is down to the duration of the flash pulse - which can be very quick indeed, much quicker than your camera shutter can achieve.

Doing a little more reading about flash pulse duration, it seems the lower the power, the shorter the duration - I suppose that makes sense, I guess I've just never had to think about it before!

It seems the trick is to place the flash 7 to 10 inches (about 18 to 25 cm), ISO 200 and f/16 and about 5 seconds of exposure. Trigger the camera then do your whatever.

On the question of camera kit, the camera doesn't seem to matter too much, as long as it can give a long exposure - I guess you could always use bulb if 5 seconds wasn't available.

The flash kit does seem to matter though as the flash duration is the key to really high shutter speeds

The SB600 will only give you 1/25000 sec. at M 1/64 output whereas the SB900 will give you 1/38500 sec. at M1/128 output - ironically the older SB800 will do 1/41600 sec. at M 1/128 output.

It seems the winner here in the high speed game is a SB800!

BTW, just for comparison, my D300 shutter will only do 1/8000 and then add some shutter lag thats way disproportionate in this game - so you can see how the flash is the way to do it!
Click to expand...

Canon Bob said:
The "Axe" has two independant outputs to trigger devices so you can set the shutter for say half a second (avoids the need to have too dark an environment) and get the flsh to fire in the middle of the shutter open time.

Bob
Click to expand...

Thanks for the information, will have a look and a read into your replies now.
 
grumpybadger said:
Bob

Thanks so much for this. I've been looking at some motion sensor stuff for wildlife traps and the Mumford Time Machine is just too expensive. I'd been considering a full "homebrew" project but am a bit short of time at the moment. The kit of this stuff looks like a great compromise.

Thanks again, off to place an order...

Paul
Click to expand...

Paul,

There are endless options for triggers....anything from trip wires to photoeyes. I picked up a microphone with mine, it works very well and the sensitivity can be adjusted through the menu system.

Bob
 
Thanks Bob.

I've just made an order for the base kit - time to dig out the soldering iron!

Want something where I can do crossed optical beams. Reckon that should be possible with this kit but need to have a play and see how to do it when its built up.

Paul
 
grumpybadger said:
Thanks Bob.

I've just made an order for the base kit - time to dig out the soldering iron!
Click to expand...

If there are any issues after the self build Paul, we can get multi-meters or oscilloscopes out and do a comparison with my working one if needed.

Bob
 
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