Dates

< November 2017 >
    1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30      

Payment methods

Payment in advance
Cash on delivery
Logo 'PayPal empfohlen'
eltima electronic > Info center > All the tricks > Water Drop Photography with Joker²

Water Drop Photography with Joker²

 

Go back

 

1 General information

In the domain of experimental photography, drop photography is steadily gaining popularity. Since our light barrier systems, especially Joker², are perfectly suited for the latter, we would like to show you how to achieve your first results in this domain, the easy way.

This document deals primarily with the general use of the necessary equipment and less with photographic or artistic aspects, such as lighting, perspectives, etc. At this point we would like to give you a brief introduction into the matter of drop photography and hope to kindle your interest in the amazing world of drops. By the aid of specific examples, we will explain the setup of the apparatus as well as the programming of the light barrier.

 

2 Preliminary considerations and process

Since drop photography aims at capturing situations that often do not even last a millisecond, exposure, or rather the exposure time, plays an essential part. It does not make sense to photograph using day- or ambient light: using the shutter speed that “normal“ light conditions allow, the drops, crests or pillars will be depicted with considerable motion blur. Therefore the use of speedlites is practically mandatory and the latter preferably in a dimmed room in order to reduce all other light influences to an absolute minimum.

At this point speedlites with a very short flash duration time have an advantage because they enable your camera to “freeze“ the situation. In the case of speedlites the flash duration lasts from about 1/2000 s (500 µs) to 1/60000 s (16 µs), depending on the type and the settings of the output power. The best solution is to operate the flash manually with a strongly decreased output. This operating mode does, however, bring about the disadvantage that the flashlight of one device will not be sufficient anymore so that several speedlites have to be used at the same time.

When determining the procedure of your photo session it is highly important to consider the triggering of the speedlite. There are two possibilities: the speedlite is either controlled by the camera or by the light barrier.

If the speedlite is triggered by the camera, the repeatability of the results depends on the variation of the camera´s lag time. In the best case the latter will be in the range of +/- a few milliseconds, but it may also be considerably higher, according to the camera model. In the stages of development and collapse of a water pillar or crest many things may happen within this small time frame, as we will see.

The triggering of the speedlite through a light barrier offers a clear advantage: here the variation of the lag time, taking light barrier system and speedlite together, amounts only to a maximum of about 200 microseconds, which can be tolerated. Therefore we settle for this method and use three speedlites, which are connected to the output b of the light barrier using a y-plug (art. no. 50048) as distributor.

Of course one can start with only one speedlite, which brings the benefit of a more simple setup. There is then, however, the constraint that when setting a decreased output power, you have less light, and when running the speedlite with high output, you may need to accept images with motion blur.

 

So, with the establishment described above the process will be the following:

  • The drop dispenser, activated by the manually triggered output a of light barrier Joker², releases a drop.
  • The drop falls through light barrier 1.
  • Output c, to which the camera is connected, is triggered by light barrier 1 and releases the camera for 500 ms. The shutter speed of the camera is set on “B-Bulb“ - thus the shutter is open at all important stages the drop goes through. For this purpose the room should be strongly dimmed.
  • Output b, to which the speedlites are connected, is triggered by light barrier 1 as well and triggers the flashes after a certain delay. The picture is being taken. The shutter of the camera remains open during this moment.
  • When the release duration of output c, being about 500 ms, is over, the shutter of the camera is shut.
  • The process is over and the picture taken.

3 Setup

Abbildung 1: Setup
 Image 1: Setup

Drop dispenser and light barrier should be safely mounted on an adjustable frame. For this purpose we use our carrier system for experimental photography (art. no. 50050, image 1-1). Firstly the drop dispenser (art. no. 50049, image 1-2) is screwed to the horizontal profile (image 1-14) of the upper frame and filled with water afterwards. The distance between the water surface and the nozzle should be app. 45 cm, measured from the lower tip of the nozzle. Directly below, with a distance of about 40 cm above water surface, one of the three light barriers of the Joker² system (image 1-3) and a reflector (image 1-4), are installed. Finally, directly below the drop dispenser, there is a basin filled to the brim with water (a salad bowl in this case), into which the drops fall.

In the case of this setup, it takes app. 220 ms for a drop to hit the water surface after it has been released. The time of the drop´s fall has to be longer than the lag time of the camera in order to make sure that the shutter is open before the drop reaches the water surface. The lag time of the EOS50D which we used here amounts to app. 150 ms. As a result of that the condition named above is fulfilled. To start with we position the camera (image 1-6) in such a way that the optical axis runs in an acute angel to the water surface. The speedlites (image 1-7) are situated fairly close to the water basin if possible.

The position of the camera and the flashes, as well as the choice of background (image 1-8), are freely selectable and should be chosen according to the photographer´s wishes. The applied light barrier can be plugged to one of the three channels; we use channel 1.

 

 Image 2: Y-plug

 


With the connection cable, which is included in delivery, the drop dispenser (image 1-11) is connected to output a and supplied with power by the power adaptor (image 1-12).

The speedlites are connected to the corresponding flash adaptors with connection cables using one y-plug each. The next speedlite is connected with a connection cable to the free jack of the y-plug, see image 2. The pins of the two sockets and the jack of the y-plug are connected with each other 1:1. As a result of that they can be used as both out- and input.

The camera is plugged to output c of the light barrier (image 1-6) using a connection set.

 

Finally, in order to be able to assess the produced pictures, we connect the camera to a notebook. This last step is absolutely optional, you will of course also be able to take good pictures without the notebook, but it can ease the work considerably.

 

 

 

 

 

4 Programming of the light barrier

4.1 Base parameters

Parameter

Value

Action mode

Simple light barrier. In our example the action mode is not used as trigger, therefore this option is unimportant.

resting time

0 ms

sensitivity

4

range

sensitive

 

Note: For our experiments, the basis parameters will not be changed any more.

 

4.2 Output a – drop dispenser

Parameter

Value

delay time

0 ms

release time

20 ms

release period

105 ms

interval

1000 ms

repetitions

0

trigger

release once

4.3 Output b – speedlites

Parameter

Value

delay time

209 ms

release time

50 ms

release period

250 ms

interval

1000 ms

repetitions

0

trigger

light barrier 1

4.4 Output c – Camera

Note: For our experiments, the parameters of output c will not be changed any more.

Parameter

Value

delay time

0 ms

release time

500 ms

release period

500 ms

interval

1000 ms

repetitions

0

trigger

light barrier 1



5 The first tests

Light barrier and drop dispenser are aligned so that the light beam is positioned directly below the nozzle of the drop dispenser. Approach:

  • We align the light barrier towards the reflector,

  • operate the switch of the drop dispenser´s adaptor board shortly in order to release a drop and to make sure that the magnetic valve and and the nozzle are filled with water,

  • switch the camera on,

  • Activate the light barrier (press <level up> to get in the alignment mode, then <level down> to get back to working mode).
    The shift from alignment mode to working mode is the (manual) trigger for output a. As a result of that the drop dispenser will release a drop.

  • When the camera is released, the drop falls directly trough the light beam. The setup works!

  • In case it does not, we shift the drop dispenser including the horizontal profile back or forth and repeat steps 4 and 5 until the camera is released.

Now that the setup works the first pictures can be taken. We switch on the speedlites and ensure that we can look at the pictures on the notebook. The output power of the flash units is reduced as far as possible. Using further test releases the correct aperture and sensitivity (ISO-value) of the camera are determined and the focus is adjusted.

 

6 The results

6.1 Hovering drops

 Image 3: Hovering drop

 

With the settings you have made you should receive a drop that is hovering slightly above the water surface on the first pictures image 3.

If this should not be the case, it is most likely because the distances between the light barrier, the drop dispenser and the water surface differ slightly from our setup. That is not all that bad since these differences can be compensated by adjusting the delay time of output b.

Now we change the delay time of output b until we receive the desired result. If the pictures show a crest, the delay should be reduced, if the drop is hovering too far above the water surface, it should be increased.

At this point it is important for you to remember the deviation of the detected delay time from the one suggested in 4.3. In the following you simply need to add or subtract it from the suggested delay time values of output b.

 

6.2 Drops on the water

 Image 4: drops on the water

 

Now we increase the release delay of output b by 1 or 2 ms. The drop will touch the water surface or will be slightly dipped into it.

At this stage you can easily see the repeating accuracy of the system since the drop moves at the highest speed. At the same time the water surface and the reflection in it are a good reference.

The distance between the drop and the water deviates about half a drop size from test to test! Here you can see the advantage which the triggering of the speedlites by the light barrier offers quite well since the lag time of the whole system doesn't fluctuate almost at all.

 

 

 

6.3 Crests

 Image 5: Crest


When the drop has hit the water surface a crest is formed first.

In order to capture the latter, we put the delay time of output b on 216 ms. A crest, comparable to the one depicted in image 5, will emerge.

By de- or increasing of the release delay the crown will be shown either at an earlier or later stage.

 

 

 

 

 

6.4 Pillars

 Image 6: Pillar

 

After the collapse of the crest a pillar is formed. Using our setup the pillar will be at its maximum with a delay time of 317 ms on output b .











6.5 Drop on peak

 Image 7: Drop on peak

 

In image 7 you can see a highly interesting stage in the collapse of a pillar. Due to inertia combined with the water surface tension a round water drop is formed on top of the pillar which seems to be resting on a peak. This moment lasts for much less than a millisecond and was, using our setup, captured with a delay time of 357 ms.

Most likely a number of tries will be needed for several reasons: this moment only lasts for an extremely short period of time and the exact development as well as the collapse of the pillar depend, apart from a few coincidences, on the water depth, the water hardness, drop size, etc.. In addition it would be wise to give several different delay times a try.

 

 

 

6.6 Drop collisions

 Image 8: drop collision

 

If the first drop is followed by a second one after a certain period of time and if the second one hits the pillar, a disk is formed (making the whole an umbrella). Using our setup, this will happen by the help of the following settings:

 

 

 

 

 

 

Output a - drop dispenser

Parameter

Value

delay time

0 ms

release time

20 ms

release periode

105 ms

interval

1000 ms

repetitions

01

trigger

release once



Output b - speedlites

Parameter

Value

delay time

310 ms

release time

50 ms

release periode

250 ms

interval

1000 ms

repetitions

00

trigger

light barrier 1

 

The delay time of output b may be varied here as well in order to influence form and size of the umbrella. The release period of output a (time between the two drops) and the size of the latter (release time – output a) also have a great influence on the result.

 

7 How to go on – further experiments

As announced in the beginning, this article offers only a small, very modest expedition through the interesting world of drop photography.

Several parameters such as delay time, drop size or the time lag between the drops in a drop collision-picture, water depth or hardness have already been introduced. Beyond that there is still a multitude of other possibilities that influence the outcome of the experiments, as for example the following:

  • Choice of medium: water, milk, oil, alcohol, etc.

  • Surface tension: In case of water soluble fluids changed by adding dish soap

  • Viscosity: addition of guar gum, sugar, etc.

  • Color: coloring of the fluid in the basin, in the drop dispenser or both

  • Configurations of the basin: measurements > 50x150cm allow photographing without a disturbing edge

  • Reflections: using black plexiglass at the bottom of a larger basin, you will receive magnificent reflections in the pictures.

  • Color filters for the speedlites

  • Height of fall of the drops

  • Water depth

  • Use of several drop dispensers with differently colored fluids

 

7.1 Examples using modified water

 Image 10: Drop collision with dish soap
 Image 9: Drop collision with low surface tension


In image 9 you can see a drop collision that is made with the same settings of the light barrier as in image 8, only with the difference of having added two drops of dish soap to the water in the basin, reducing the surface tension.

Due to the low surface tension a disk, and with it an umbrella, can hardly be formed. Instead other, bizarre forms are created.

The collision in image 10 was created by reducing the delay time.





 

 Image 11: Pillar with low surface tension

 The pillar in image 11 was taken with the same settings as the one in image 6, but with dish soap in the  basin. As a result of that it is a lot more slender and higher.

 

 

 

 

 

 

 

 

 

 

Go back