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  • Enrique Izquierdo

Water droplet collision

Actualizado: abr 25

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

A simple dropper that dropped drops of water on a regular basis at indeterminable intervals of time, was how I started. With this method, you obviously couldn't adjust the drip time or the size of the water droplet. Little by little, investigating and asking people who were far ahead of this was the way to capture the collisions of drops of water with the camera.

The biggest problem was in managing to drop drops of water at the exact point and at the exact moment, while the camera fired and the flashes were also fired at the right moment. (later I will explain why I say flashes and not flash)

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 dedicated space just to take these photographs since mounting and dismounting everything takes time so it is convenient to mount it and be able to have it there just for this.

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

THE EQUIPMENT





CAMERA


Most are made with a Canon 40D.


For some time now I do them with a Canon 5D Mark III.




Exposure times are typically very long, causing significant noise in photos, but the 5D has very good noise handling, which dramatically improves photo quality.


LENS

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



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

FLASH


Since the diaphragm is very closed for the reason that I have explained before, it would be logical to think that the flash lighting should be at maximum power to compensate for such a small light input. Nothing is further from reality. If we put the flash at maximum power, the light time is too long to freeze the image and it would be blurred. 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 short light time, so the photo will freeze.

Keep in mind that this type of photography is made, as I say, only with the light of the flashes while the camera mirror is raised. And that is why the shutter speed is NOT a determining factor, but the time that the flashes are illuminated. Of course, the room must be dark or in semi-darkness to avoid undesirable lights.

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

Some have the Yongnuo Speedlite YN560-II and say they do very well. I bought some Vivitar 285 to which I made a modification to be able to vary the intensity to my liking.


In this link I leave you the instructions to make these modifications: https://www.dropbox.com/s/oncxeiok5okoicp/Vivitar 285 Tutorial.pdf? Dl = 0

(Sorry, it was sent to me by Markus Reugels and it has not been translated. )

DRIP AND CONTROL ELEMENTS

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



The success of the drop collisions will depend on the configuration of the times.


This controller has an input for the infrared ray sensor (which I show you 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 count, we need to be done by sound instead of 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 that I place at a height of 55 cm. This height is variable, you will have to do multiple tests until you find the height at which the effects you want are produced. The opening time of the solenoid valve, of course, is configurable. The more milliseconds open, the larger the drop of water. The solenoid valve is this:



solenoid valve


And it is the one you have to screw into the Mariotte siphon:



Mariotte siphon

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

The next item is an infrared ray sensor:




sensor



When the solenoid valve releases a drop of water, it passes through the sensor arc which sends the information of the exact position of the drop of water when it falls to the controller so that it begins the cycle that we have programmed for it.


support

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

THE WATER


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


guar gum

Guar gum gives the water a sufficient viscosity so that the drop of water does not "break" when colliding with the column that creates the first when falling. To mix the guar gum with the water, I advise you to dissolve the capsules separately in a little alcohol and then add it to the water. This will avoid problems with lumps. Once mixed, you will have to strain with a cloth or a cloth strainer to remove the cloudiness.

The color I give it with food coloring:

food coloring


When I want to make collisions of two colors what I do is put a coloring in the water of the mariotte siphon and another color in the water of the container below. With this we achieve that the upward column that creates the first drop is of one color and the second drop, which is the one that hits the column, of another.



OTHER USEFUL ELEMENTS


Focus is an important point and you have to constantly monitor it. Of course, the objective will have to be set by the manual. I use one of these two elements as an aid to focus:



ayuda para enfoque


The one on the left is the tip of a silicone cartridge into which I have 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 assembled (Controller, valve with siphon, water, container where the drops fall) you will have to drop a drop of water so that it impacts right on the tip of the screw or on the thin tube, and once you have Achieved, you will have to make as precise a focus adjustment as possible right there.

From here on, you obviously can't move the tripod anymore. Keep in mind that it's easy to trip over a leg and goodbye to focus. I tell you from personal experience. In any case, it is necessary to be constantly monitoring the focus. It's fundamental.

Other elements that will be very useful are the pressure clamps and / or the sergeants. You always have to hold cardboard, Plexiglas plates, cables, etc.


Pressure tweezers



sergeant


PROCEDURE

Diagram of a typical setup


(1) Remote flash trigger (emitter)

(2) Container filled with water

(3) Opaque white plexiglass sheet

(4) Flashes

(5) Remote trigger receivers

(6) Mariotte siphon water tank

(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 that I show you can be varied to your liking.




Assembling this diagram would result in this type of photo:As I told you at the beginning, this tutorial is a starting point and of course, the diagram that I show you can be varied to your liking.




Assembling this diagram would result in this type of photo:


While the camera that is in bulb mode fires approximately 0.5 seconds, at the moment of the collision, the flashes that pass through the opaque white plexiglass plate that works as a light window are fired.




You can play with the position of the flashes and the position of the camera to obtain different results. Even on many occasions it is convenient to illuminate the collision from the side, so we will have to distribute the flashes around the container where the collisions occur.




You will see 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 perfectly explains its operation and how to set the different Triggers (outputs for solenoid valve, flash, camera), how to save a configuration, etc. So I'm not going to elaborate on it.




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

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

YOUR FIRST COLLISION


- We start from the base that we have the siphon filled with water with guar gum, the flashes connected, the StopShot on, the manual shutter connected to the camera, the focus well done, etc.




- First, I place the solenoid valve perfectly vertical, this is important because otherwise the columns will not be vertical (they will lean to one side) so 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 sensor does not appear in the diagram)




- I connect the solenoid valve to Trigger 1 of the StopShot.




- In the Trigger 2 of the StopShot I connect the remote flash trigger. In the diagram, the shutter is positioned over the camera. We would have to manufacture an RCA-flash shoe cable to place the trigger here.


- Program the StopShot like this:


T1 --------------> Manual

(For the controller 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 the solenoid valve. First drop)


TOFF 1 ---------> 76 ms (Wait 76 milliseconds)


PULSE 2 --------> 25.0 ms (Second opening of the solenoid valve. Second drop)


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


T2 --------------> 275 ms

(Timeout 275 milliseconds and flash fires)



- I would shoot the camera with a manual shutter. The firing sequence would be:



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


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


3) Release the manual trigger


- Admire your creation




All these values ​​are indicative and you will have to change them quite frequently. Keep in mind that the fact of working with such small time values, any environmental condition can make you have to modify some values ​​that were working well for you at first, but suddenly stop doing so. It is a work of a lot of patience and trial / error.


Enrique Izquierdo



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