18 de Décembre, 2016 · Técnicas · 1 commenter ·

Collision of water droplets

      First, say, that this tutorial is the result of a long tour of instruments (drippers, timed relays, Arduino boards), techniques, devices, methods, tests, queries and a long etc. Which have resulted in what I am going to show here.

 

      A simple hospital dropper that dropped drops of water on a regular basis at indeterminable intervals of time, was as I began. With this method, I obviously could not adjust the drip time or the size of the drop of water. Little by little, investigating and asking people who were far ahead of this was the way to capture with the camera the collisions of water droplets.

 

Indeed, doing this type of photography requires a lot of patience but also a varied endowment of means to be able to capture that magical moment that the eye is unable to retain.

 

If you can afford it, I would advise you to have a space dedicated just to make these photographs, since mounting and dismantling takes time so it is convenient to mount it and to have it there just for this.

 

What I intend with this tutorial is to give you the starting point to take photos of drops collisions and from here, either by modifying values of height, times, water densities, etc. experience and get incredible photos.

 


Equipment 


 

CAMERA

Most are made with a Canon 40D.

 

Of a time to this part I do with a Canon 5D Mark III.


Usually the exposure times are very long, which causes a significant noise in the photos but the 5D has a very good treatment of noise, which improves the quality of the photo incredibly.

 

 


LENS


You can choose the lens you want (as long as it is not an angle), I use the Canon EF 100mm f / 2.8 USM Macro.

 

We all know that the sharpness provided by a macro over short distances is not obtained with another type of lens. The problem with which we find is that the depth of field is very small and that is why I always make these photos with a fairly closed diaphragm between f / 14 to f / 22.

 


FLASH


Since the diaphragm is very closed for the reason I explained earlier, it would be logical to think that the flash illumination should be at maximum power to compensate for such a small light input. Nothing is further from reality. If the flash we put to the maximum power, the time of light is too long to freeze the image and this one would leave us moved. Therefore I use two or three flashes at a power of 1/32, 1/64 and even 1/128. What we get with this is to have enough light so that the photo does not come out dark and with a very small light time with which the photo will freeze.

 

 

     It should be noted that this type of photography is made, as I say, only with the light of the flashes while the camera mirror is raised. And this is why the shutter speed is NOT a determining factor, but it is the time that the flashes are illuminated. That yes, the room must be dark or dim to avoid undesirable lights.

 

 

     We have to think very well what flashes to buy because the price would have to be multiplied by two or three according to the number of flashes we are going to use.

 

 

     There are those who have the Yongnuo Speedlite YN560-II and say they do very well.

     I bought a Vivitar 285 to which I made a modification to be able to vary the intensity to my liking.

 

In this link I leave the instructions to make these modifications:

 

https://www.dropbox.com/s/oncxeiok5okoicp/Vivitar%20285%20Tutorial.pdf?dl=0

(It was sent to me by Markus Reugels and does not have it translated.)

 


CONTROL AND DRIP ELEMENTS


The StopShot controller is the device I use to control all dripping elements, flashes and even the camera trigger.

      Of the configuration of the times will depend the success of the collision of drops.

      This controller has an input for the infrared sensor (which I show below) and three RCA outputs where I connect the solenoid valve, the flashes and also the camera.

      It also has a microphone input. Sometimes the time counting, we need to be done by sound instead of by cutting a beam of infrared rays, but this would be for other types of photographs.

 

StopShot Controller

 

The drops are produced by the opening of a precision solenoid valve which is about 55 cm high. This height is variable, you will have to do multiple tests until you find the height in which you produce the effects that you want.

      The opening time of the solenoid valve, of course, is configurable. The more milliseconds of opening, the bigger the drop of water.

      The solenoid valve is this:

 

solenoid valve

And it is the one that you have to screw in the siphon of Mariotte:

 

siphon of Mariotte

 

The function of the siphon of Mariotte is to always maintain the same pressure in the water tank even if this is gradually emptying.

 

 

      The next element is an infrared sensor:

 

 

sensor

When the solenoid valve releases a drop of water, we pass it through the sensor arc which sends the information of the exact position of the drop of water as it falls to the controller to begin the cycle we have programmed.

 

Support

Of course, these last three elements, can be placed in a tripod with a support thought for it.

 


THE WATER


 

      If we did these photos with only water, the moment of the collision would be an endless number of microdrops that would not give us the result we expect. Therefore I add between two and three capsules of guar gum per liter of water. (This is variable and to your liking):

 

 

The guar gum gives the water a sufficient viscosity so that it does not "break" the drop of water when colliding with the column that creates the first one when falling.

      To mix the guar gum with water, I advise you to dissolve the capsules separately in a little alcohol and then throw it into the water. This will avoid problems with lumps.

      Once mixed, you will have to strain it with a cloth or a fabric strainer to remove the turbidity.

      The color is given with food coloring:

 

When I want to make two color collisions, what I do is put a dye in the water of the siphon of mariotte and another color in the water of the container below. With this we obtain that the column up that creates the first drop is of one color and the second drop, that is the one that collides against the column, of another one.

 

 

 

 


OTHER USEFUL ITEMS


 

      Focus is an important point and you have to be constantly watching. Of course, the objective you have to put the manual. I use one of these two elements as an aid to the focusing:

 

 

The one on the left is the tip of a silicone cartridge to which I screwed a screw and the one on the right is a very thin tube attached to a solid and heavy base.

      Once you have everything installed (Controller, valve with siphon, water, container where the drops fall) you will have to drop a drop of water so that it hits just the tip of the screw or the thin tube, and once you have Achieved, you'll have to make a focus adjustment as accurate as possible right there.

      From here, obviously you can no longer move the tripod. Keep in mind that it is easy to stumble with a paw and goodbye to focus. I tell you from personal experience. However, it is necessary to be constantly monitoring the approach. It's fundamental.

 

 

      Other elements that will be very useful to you are the pressure clamps and / or the sergeants. Always hold paperboards, plexiglass plates, cables, etc.

 

 

 


 

PROCEDURE

 


 

Diagram of a typical setup

(1) Remote flash trigger (emitter)

(2) Container full of water

(3) White opaque plexiglass sheet

(4) Flashes

(5) Remote Shutter Receiver

(6) Water tank with siphon from Mariotte

(7) Solenoid valve nozzle

(8) Precision Solenoid Valve

 

As I told you at the beginning, this tutorial is a starting point and of course, the diagram I show you can vary it to your liking.

      The setup of this diagram would result in this type of photo:

 

While the camera in Bulb mode is triggered for approximately 0.5 seconds, at the time the collision occurs, the flashes that pass through the opaque white plexiglass plate that works as a light window are triggered.

 

 

     You can go playing with the position of the flashes and the position of the camera to obtain different results. Even in many cases it is advisable to illuminate the collision sideways so we will have to distribute the flashes around the container where the collisions occur.

 

 

     You will observe in the diagram that to avoid too much wiring I use a remote flash trigger (1) with receivers in each of the flashes (5).

 

 

     The StopShot comes with a manual where it explains perfectly its operation and the way of putting the different Triggers (exits for solenoid valve, flash, camera), like saving a configuration, etc. So I will not dwell on it.

     If you want to have a look, the link to the manual is this:

     https://www.cognisys-inc.com/downloads/StopShot%20Manual%201.8%20English.pdf

 


      YOUR FIRST COLLISION


 

- Starting from the base we have the siphon filled with water with guar paste, the flashes connected, the StopShot on, the manual trigger connected to the camera, the focus well done, etc.

 

 

     - Firstly, I place the solenoid valve perfectly vertical, this is important because otherwise the columns will not be vertical (they will lean towards one side) with which the collision will not occur.

 

 

     - The distance between the lower tip of the nozzle (7) and the surface of the water in the container (2) is 54 cm.

 

 

     - The distance between the lower tip of the nozzle (7) and the infrared sensor is 13 cm. (The diagram does not show the sensor)

 

     - On Trigger 1 of the StopShot, connect the solenoid valve.

 

 

     - On the Trigger 2 of the StopShot I connect the remote flash trigger. In the diagram, the trigger is placed on the camera. We would have to make an RCA-flash shoe cable to place the trigger here.

 

 

     - Program the StopShot as follows:

          T1 --------------> Manual (For the driver to wait for the Up / Down button to be pressed)

          #PULSE --------> 2 (Number of solenoid valve openings 2 drops)

          PULSE 1 --------> 50.0 ms (First opening of solenoid valve, first drop)

          TOFF 1 ---------> 76 ms (76 millisecond wait)

          PULSE 2 --------> 25.0 ms (Second opening of solenoid valve, second drop)

          TOFF 2 ---------> 16.0 ms (Default)

          T2 --------------> 275 ms (Standby time of 275 milliseconds and flash fires)

 

 

     - The camera would shoot me with a manual trigger. The trigger sequence would be:

          1) With the camera in Bulb shoot with the manual trigger.

          2) Press the Up / Down button to execute what we have programmed.

          3) Release the manual release

 

 

     - Admire your creation

 

 

All these values are orientative and you will have to change them quite frequently. Keep in mind that working with time values so small, any environmental condition can cause you to have to modify some values that in principle were working well but suddenly stop. It's a lot of patience and trial / error work.

 

 

 

 

      I have a tutorial for adjusting the sharpness in Photoshop in which there is a video of Markus Reugels that does this same thing I just told you but with three solenoid valves and another controller, look at it, it is interesting to illustrate more this tutorial. The link is this:

http://www.enriqueizquierdo.com/lang/es/blog/ajuste-de-la-nitidez-con-el-filtro-paso-alto

 

 

 


  *** (If you have arrived here, leave me a comment giving me your opinion, whether you liked it or not.


 

Enrique Izquierdo

 

Alex Diaz
22 de Septembre, 2017
Hola Enrique. Excelente tutorial, muy detallado y bien explicado. Se agradece el esfuerzo por compartir tu conocimiento y experiencia. Tengo una consulta, crees que es casi imposible lograr buenas fotografías de colisión de gotas sin el controlador electrónico?
Gracias y saludos desde Costa Rica.

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