High speed shots

[Don Hoey]

Question Lello,

Out of interest before you produce yet another stunner, what is your other flash ?

Don

[Lello]

I mentioned to you a while back, A YinYan, I got it when I had my Pana
FZ30, When I was looking for a low voltage unit. But it hasn't got a PC sync socket, so I use a remote slave attached that has got a PC sync and a light sensor.

[Don Hoey]

I guess anyone trying high speed pics has a go at the splash. So todays mission was to see if it could be done with a variation of the contact trigger.

For the first attempt I thought to use the liquid as part of the circuit. Despite making contact through a meter it failed to trigger the flash. Electrical boffins will know why that is.

A bit of a think and I decided on a floating trigger using a bit of foil. The idea being that anything dropped into the liquid would create a wave. The foil would ride the crest of the wave and so make contact with the fixed terminal. This works fine everytime so long as the top of the foil is dry along with the fixed contact. Any wetness here and it will fail to trigger the flash.

Water was put in the bowl up to 10mm from the top. The trigger was then positioned before adding the remaining. The foil floats well enough so it is quite easy to raise the water level and float the foil up to give a gap of around 1mm. This spacing is dependant on how large an object you intend to drop since it must be less that the wave that will be generated. 1mm is fine for an ice cube but for something smaller that and gap would need to be smaller and or the trigger placed closer to the impact point.

Provided the contacts are dry and a suitable gap is set this is guaranteed to work every time. My only failures were through forgeting to connect the flash , not topping up the water after that failure , and two more before I realised the significance of wet contacts. So 6 frames were taken to get the gallery pic and the full frame posted here.

Attatched is a pic of the floating trigger, a full frame showng the contacts, and a behind the scenes shot.

Don

PS : As the wave rebounds from the container side it will trigger the flash again as the foil rides the wave, so an assistant to cover the lens with black card directly the first flash burst is over is advisable if you are using a long exposure like me at 2 secs. 2 secs chosen for trigger the camera and drop the ice cube.

[Lello]

Very Well thought out Don, Thank god for tin foil Very good to get that shot after only six attempts

[Don Hoey]

Originally Posted by Lello

......Thank god for tin foil Very good to get that shot after only six attempts

Always a challenge to do things on the cheap.

No problem once you have worked out a reasonable gap between the contacts for the effect you want. Larger the gap within the boundarys of the wave height the greater the delay. Trigger is guaranteed to trip the flash.

Two more from yesterday. I started by testing with a Trebor mint dropped into a glass. This was when I discovered that although water conducts electricity it is not good enough to trigger the flash. Staying with the glass I then tried the foil float. Problem for me was trying to get the contact gap right in the confines of a glass. Eyes are not what they were. So I moved onto a larger bowl.

Pic 2 is the result of too greater contact gap, so too great a delay. This was because I did not top up the water from a previous failed attempt when I forgot to connect one of the flash terminals. You can see the waves created by the cube though.

Don

[Don Hoey]

A harder job today. It took all afternoon to make up the sequence even though I only did 8 drops. A couple missed the trigger altogether. Not so easy doing this in a dark room.

The first job was to remove some screws from the camera so it would break apart on impact.
For each drop the camera was fully assembled minus the screws I had removed. So for each drop the camera had to be re-assembled, and the top foil sheet from the trigger replaced. In order to try and change the delay, tension on the top foil was increased from a bit slack to drum tight.

The trigger was the same impact job as in 'Lights Out'. Lighting was also the same with the addition of a reflector on each side.

To increase dof ISO was upped from 200 used for the light bulb to 400 allowing for an aperture of f8.

Link to the shot http://www.worldphotographyforum.com...6&limit=recent

Don

[Lello]

Very well thought out Don, You seem to be getting nice lighting (but of course you the lighting man ) I can't wait for my remote slave trigger, and some sort of idea on what to use the sound trigger on You keep coming up with such good ideas.

[Don Hoey]

Originally Posted by Lello

........... and some sort of idea on what to use the sound trigger on

Lello,

Light bulb would be great with a sound trigger as you could set a far longer delay than I can at the moment, although trials will continue when I get the next dead one. So if you use a hammer then try a delay to give the head half way through the bulb. Now that would look impressive.

I will have to think about sound trigger shot possibilities, as in my mind I have been thinking impact only as sound is not an issue.

A lot that I have seen on the net involves the subject breaking light beams to trigger the flash. No cash for that kit but I am not detered. I will find another route that does not cost. For me solving that is all part of the challenge.

Don

[Lello]

Hi Don I will try and buy the remote flash sensor over the weekend (if the shop have managed to get some in) then I will try some more shots using the sound trigger and bulb (I might try bulb hitting the ground).
By the way I have been given about 5 used disposable cameras, I might see if I can use the flash's out of them (some how wiring them together with a battery) to make some sort of ring flash any ideas on how to get them to fire? maybe using the same remote flash trigger unit?

[Don Hoey]

Lello,
I will have a look to see if anyone has posted a pic of an open disposable camera on the net. THE MOST IMPORTANT THING if you dismantle one to get at the flash is to earth out the capacitor. Even a disposable with its tiny flash could give you a serious belt.

Whatever you try with the bulb consistancy is the thing. So if it is a drop, then you need to arrange some sort of height marker to ensure that. On my Oops shot the final frame was dropped from a bit higher than the others which I am sure contributed to the extra bounce. If you look at my bulb shot and then imagine the hammer at half way through the bulb then you would probably be talking a few milliseconds.

I am also looking at a new shot but I think I am going to have to make up a trigger specially for it.

Don