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All right, good morning, everyone, thank
you for the nice introduction.
I'm Polygon and I
want to talk to you about low
cost, high speed photography.
So I started doing photography
as kind of a hobby about
eight years ago.
And after going through the usual phase
of doing everything from, I don't
know, Panorama's to macro's,
I kind of concentrated on
studio photography and
being a student with
limited room available.
I kind of improvised a lot
with what was there
and around at that time.
I also watched a lot of YouTube
and Vimeo videos which were partially
high speed, high
speed action, and I
wanted to do this myself.
And since I didn't have twenty thousand
euros to spend on a phantom flex,
high speed camera, I started
looking around to try
to find out what I can do with
my camera and the other equipment
I already had.
And so this talk is
basically a mixture of a tutorial.
So I did a lot of research on the
Internet.
And so here is what the final result
looked like as well as
like a slideshow.
So to give you an idea,
what is this all about?
Here's two pictures.
So the first one, this is
called chalk being smashed
by a mousetrap.
And it gives this kind of
exploding rainbow effect, if
you will.
And another example
is this.
This one, this is a water
balloon right at the moment
where it pops.
So you can see in the lower right corner,
the rubber skin
is still partially intact,
whereas on other places
the waters are the water is already
basically splashing out.
So.
Just to formulate the requirements,
just talk about freezing some very
fast action and the action is fast in
two senses.
So the first thing, it just happens
very fast.
So you need a very, very
short exposure time of
roughly 150, thousands to 110,
thousands of a second.
And since these things look
good only for, let's say, a couple
of milliseconds afterwards,
the water has splashed out a lot.
So it's no longer interesting.
You also need to time the exposure very
precisely. So roughly
with the precision of one millisecond
is desired.
Now.
Common digital cameras,
they fail both of these requirements.
So even if you look at high end
laws, I think
I've seen one over a thousand
of a second.
Um.
But they cheat, so the way a camera
shutter works in eight years, it has
to curtains.
So basically, when you start your
exposure at the first curtain moves down,
it exposes DICENZO to the light
and at the end of the exposure, the
second curtain moves down, blocking the
light. Now if you take a
picture faster than roughly one five
hundredths of a second, they start
moving the second curtain down.
Before the first has opened, there was
basically a slit moving over
the sensor. So every part
gets one eight seconds
of light.
But basically the top of the
image will show you something earlier
than the bottom of the image.
So essentially the camera will
be taken completely out of this.
And an alternative
is fleshless.
No flushers, most commonly
known in this
form. So they have the flashbulb
on top. Then there is usually
some kind of settings panel and
on the bottom there is the hot new
value slided
on the camera.
So what can it do
for us to help in
taking these pictures?
So let's go back to the very basics and
compare flesh with an ordinary
lamp. So if you have an ordinary lamp,
it's basically characterized by giving
off a certain amount of light
per time.
So the amount of light you capture
in the frame basically depends
on how long your shutter is open.
That's, I guess, not
a big surprise to anyone.
Now, if you compare this with
a flash,
a flash, just basically a capacitor
and a flashbulb and a capacitor
as charged, and then it discharges over
the flashbulb, creating
insane amount of power, several kilowatts
for a very short time, giving off these
very fast pulses of light.
So basically,
as long as your shutter is
open, when the flash fires,
you will always get the same result.
No matter if you are exposed for like one
tenth of a second or 10 seconds.
The only thing important is your shutter
is open when the flash fires.
And this is what I'm
going to use to my advantage.
So putting this together,
if you take a picture in complete
darkness, so
only the only light source is
the flash, then
the actual exposure you are going to get
will be independent of whatever you set
on your camera and
your effective exposure.
Time of the image becomes
equal to the flash time.
So basically how long the flash
is on.
Now I.
I searched Google to find
the flash burn time for common
flushers and it turns out
it's in your manual.
So this is from my flash.
It's a Nikon SB 900.
And so you can see that the flash
duration or the burn time
depends basically on the power settings.
So if you fire the flash at full power,
you'll be roughly Gane one thousands
of a second.
And if you tune it down to two, the
lowest power setting, you see
a flash duration of roughly 140
thousands of a second.
And so that's pretty good.
That's actually within the desired
exposure times that I was aiming
for.
And what is also very nice by
changing the power settings
excuse me, we actually have some control
over the exposure.
So that solves problem one, the very
short exposure time that is required
to basically freeze the image in place.
Now, just to give you an idea
of what a high power versus a low power
flash actually looks like.
So on the left, you see a picture taken
with almost full power
and you see these small water droplets
flying out. They become streaks.
That is because the exposure lasts
almost for a millisecond.
So you get this very dynamic
image, whereas on the right side you
see a picture taken with a very low power
flash. So everything is really frozen
in place and
it's basically, yeah.
Frozen at the moment.
So there is, of course,
no absolute truth here.
It depends on what picture
you want to take,
how you select your your flash power,
basically.
So now, having solved this problem, I
already told you that
in digital cameras are too slow.
They also have quite a long delay
when you file them of at least one
hundred milliseconds, which is a
much too long.
So how can you trigger the flash
without a camera?
And the first way it may sound
ridiculous, but you can do it manually,
so most flashers have a button
on the back and when you press the
button, the flash will fire with
whatever power setting you currently
had.
No, of course, this is very inaccurate,
but it's also very easy to do.
And I actually took some pictures that
way, which I am going to show you later.
But of course, at some point
you want to move to bring a
microcontrollers into the picture.
So the most obvious way would
be to interface with the flat flesh
you. So this is how a flash
looks from below on the left side.
It's quite a new flash.
It has five contacts
for like digital
communications, for measurements, for
several signals.
So modern fleshless have lots of
functionality, which we don't need
to. Right.
What you basically show is a very old
flash. It has just one contact.
And this contact is called
Hexing for experiencing
because SINNEN is what's in the bulb.
And the only thing that I'm going
to need is this xanthan.
And as you can see, if you compare the
two pictures, it's also there on the left
side. That's because
there wasn't a standard for this and it
defines the pin.
So all the flashes that were made in the
last 25 years and therefore what you
will probably work.
So you have really a lot of flashes
to shop for, which
probably makes it quite cheap.
Now, unfortunately, this hot issue is
very tedious to work with.
So those contacts are basically spring
contacts. They will slide back in
when you push them.
And so attaching something to it is
this quite tedious.
So there is another method which is
called PC.
This was actually how you fired the Flash
before. That was the hot issue.
So you basically had these cables that
you see on the left with this
weird connector there.
And it's still being
used in studio flushers and
in also a high end
on camera flushers.
However, the cheapest models, they
only have to hot you.
But luckily you can get these these
adapters for like 10 euros
and they basically will convert
your HjÃ¶rtur to a PC using
cable. And you can get the cables with
a standard headphone
jack, which is very easy to use in
microcontroller circuits.
So how do you actually find the flash?
That's very easy.
You connect the accent to ground.
So ground on the issue is basically
the metal layer outside and
on the PC. So it's one of
the signals carried with it.
And when you do that, the flesh will
fire.
So that brings me to the last question
regarding flushers, and that is, how
accurately can you fire them or what is
the delay?
So I did not find a lot of
information, so I decided to measure it
myself.
So you can see here, um,
basically a scope measurement of the
signal shown in green starting
on the top left.
And the yellow signal is
the response of a photo diet
which was placed in front of the flash.
And so you can see the green signal
basically goes to ground, which triggers
the flash to fire.
And then in the second quarter
of the after picture,
the photo diad responds and I don't
know if you can see it.
There is a time delay
of thirty nine microseconds
between these two events.
So let's say roughly 100
microseconds. And I repeated this
measurement.
Probably 10 times, and
it's very accurate, so the variation I've
seen is within two
microseconds, so basically
negligible.
So that solves the problem, too.
So apparently we can file this flesh
in a fraction of a millisecond,
which is very good.
So how would, you know, go and
connect your flesh to
a microcontroller?
Basically, the circuitry is as simple as
it gets.
So you connect to
hexing support to some
random digital input
of your microcontroller.
You can use our one as a current
limiter. But to be honest, I
didn't bother with it.
It just worked and.
There's two things to
to do correctly here, because otherwise
I've seen a very overt behavior from your
flesh.
So the way this works is the support from
the flesh. It carries a voltage of
three point three or five watts,
and it's basically
being put up internally by the flesh
and it sends us when some external source
pulls this pin low.
So you do not want to drive
extra high from your microcontroller,
so don't use any pull up resistors.
And even worse, don't configure
dependance, output and pull it.
I've seen very strange behavior
happening when I did this.
And the second thing, when you
pull the pin low, only do
so for a short time, like one or two
milliseconds and then basically
release it again.
Otherwise your flesh
will also start to behave
strangely minded.
So it's stopped firing for a while.
You had to take out the batteries.
Apparently you can confuse them quite
a lot by by keeping the
pin low for too long.
Now, one very important thing to make
sure is you should check the voltage
that your flesh gives you on the pin.
This is not standardized.
So I've seen flashes worth three point
three and five volts, which is very
convenient for microcontrollers.
But I've also seen flashes
with 12 or even 24 worlds
where your microcontroller may actually
be damaged. So in that case,
you may need a little bit more
and elaborated circuit, maybe use up
to a couple of years to kind of
completely separate the two circuits
electronically.
And if you have a very, very old flash,
you should actually make sure
that they don't basically
put the actual flash circuit on there.
So in the very first flushers,
you basically had to 400 volts.
That is on the flash capacitor right
on this pin.
And so the camera would close the
circuit.
And really in a flash
capacitor, there's enough energy to
to knock you out or even kill you.
So if your flash is like twenty
five years old, please check that.
Please don't die.
It's not worth.
All right, so just as
a short recapitulation of
what the flesh does for us, it
gives us a very short exposure time,
roughly 140 thousands of a second.
It's super easy to control with a
microcontroller. So you don't need
to be an electronics expert.
It has a very short firing delay
of 100 microseconds and it basically
fires a super accurately.
So with that being out of the way,
here's how you take a high speed picture
in seven easy steps.
So the first step is you build your set
up so kind of,
I don't know, put up reflectors, put up
a background place, whatever
action you want to take a picture of.
And when you're done that, you're
talking to room and you start a long term
exposure on your camera.
Now, this may sound a little bit
counterintuitive for high speed
photography, but
as I said earlier, since the room is
dark, the exposure
time when your camera doesn't matter at
all. So you might as well as well make
it a long term exposure to kind of give
you enough time to work with.
Now, during this long term exposure,
you start your high speed action.
So I don't know, you fire your crossbow
at an unfortunate episode or whatever.
Um.
You have a microcontroller somewhere
in there and.
It was sense that the action
has started, so maybe it is
sensitive to sound.
There may be a light barrier, something
is flying through or just some
simple improvised switching
going on.
And after the microcontroller senses the
action, it basically it's in a
delay. And after delay delay,
it fails to flash.
So then you wait for your camera
to finish your exposure
and then you will well review
your result.
And most certainly
probably 99 of 100 cases
you will not be satisfied.
So you improve your setup and then you
repeat it all again.
Now, there are two little points I didn't
really talk about yet, and that is how
to build a set, how to do this,
and also how to let the microcontroller
sense whatever action you are doing.
And that is because,
unfortunately, these two parts are
very specific to what you are trying to
do. So instead of giving you more theory,
what I will do is I will explain
to set ups that I did.
I will explain how I built the sets, how
I made the microcontroller sense, the
action to hopefully give you an idea
that you then can build your own setups
on.
So let me start with
the first one.
This is about poking water
balloons and taking
pictures of how they
pop up.
This is the setup.
This is my
bathroom back when I was living in
a dormitory.
And as you can see, it's quite
ticked up.
So there is the camera
on a tripod.
You can see all those cables
around the toilet where the
microcontroller is sitting.
And
that's probably not taking it.
At least I hope the camera's
pointing to the shower
where there is a black curtain
and there is to
basically kuruvilla pods combined
into a function called Alapatt, holding
this scary looking device with a lot of
duct tape.
And you have a flash
on another tripod with a
self-made soft box.
Now you notice the walls.
They are white, which is very lucky.
Otherwise, you would want to put white
fabric there.
And the reason is photographic lighting.
So the only light source
there is is basically
the flash.
And if you notice, typical
flash pictures, they have very hot
shadows. And basically
what you want to have is you want to have
lots of reflection coming from the sides,
from the top, from the bottom, just to
give you a more smooth lighting.
So that's why everything that is
not the background should be
as bright as possible and
ideally white.
However, before, um,
starting to take pictures with this
pokey stick, um.
I did some pictures manually because
I, uh, I took most of these pictures
together with a friend, Chris,
who unfortunately is for this Congress,
and he was very skeptical about
the whole idea. So he said, before I
start programing microcontrollers,
I want to know that this at least can
work.
So I said, OK, we try
manually. And apparently he trusted the
idea enough that
he let me set up a water
balloon that he was holding in his hand
with a knife in complete darkness
while triggering the flash with my other
hand.
So I know it always takes
a bit of magic out of the whole process,
but just to give you an idea of what you
can expect, this is how the picture
came out of the camera and
a little bit of magic later.
It's actually not a lot.
You don't end up with this.
I've already shown it as
an example,
but it's not another long
way. It's a little bit of contrast, a
little bit of sharpening.
And you basically got this.
So the second example would be
this picture. I have also shown it in the
beginning. But just that you see
again how it comes out of camera and
how close the knife was to his fingers.
So and again, the end
result that you've already seen.
So that we are
two lucky shot and
in between there are a lot of shots
that look like this, so if you do it
manually, you will get
lots of crap, basically.
So you may fire the flash before
you may fire the flash.
Way too late, but also you can
see in the top right arm.
This is basically not
much too late when the Flash fired,
but you can see the water droplets, they
already spread out all over the frame.
The water itself has moved to this
strange mess.
So really, this process
looks only good for the first
few milliseconds.
And afterwards, at least in my opinion,
it becomes largely uninteresting.
So let's finally bring microcontrollers
in the picture.
So this is the water
balloon pop sensor in big.
It's pretty simple, really.
So basically it does a wire connected to
the body using this crew
there.
And there is a second open wire
very close to the
poky end of it.
And the idea is the water balloon falls
under the water, creates a connection,
and this is what turns our
microcontroller.
Now it's time to to trigger
the exposure.
So here's a bit of.
The circuit I attended
in the more famous symbol,
so.
Again, it's not rocket science,
you have to sense, which is the digital
inputs, it's being put
with a pull up resistor to
five watts and it connects to the
open end.
And actually the ground contact
does connect to the body
of this work quick.
And so once the water drops
in there, this little
dashed circuit, they are closer's
pulling descends. Pillow's with a
microcontroller, sees a falling edge to
interrupt Fragos and the explosion
starts. So that's really as simple as it
gets.
So, yes, a little bit of code.
It's the actual interrupt service routine
I used to not, you know, because
it was there and it worked.
So use whatever you want.
Um, I hope there is not a microcontroller
that does not have two digital Io's
and one interrupt.
Otherwise it probably sucks pretty hard.
So there's basically four things going on
here. The first thing is, of course,
disabling to interrupt is very important.
Then there is a delay loop
and the two lines in the middle, this is
basically a deep bouncing.
So in that case, um.
If there was if the signal was going
high again while you were waiting,
then the waiting loop would reset,
I think, for the water balloon shot.
I actually commented this out because you
want to trigger on the very first signal
for the most webshots.
I am going to show you later.
You probably want to have this.
So decide what works.
Try it out then.
Here, the flash is fired.
So not by riding low to the output that
was already there, but the port
was previously configured as an input.
So to the Flash, it will look like a very
high register to ground.
So basically like an open pin.
And that's exactly what the Flash wants
to have.
So it wants to drive its spin and
not be bothered with it.
And you only pull it to ground for
like a very short time to trigger the
flash.
Then this part is another delay.
It waits for roughly two milliseconds
and then basically reconfigures the pin
as an input, which tells the Flash,
get ready for the next shot.
And then finally the system
goes disarmed and it also turns
off an allergy.
And to start it again, you press the
reset. So that's not really a UFO.
Now, if you want to
call it, it's on its own GitHub.
It's really very simple.
So if you want to improve on that, be my
guest.
So testing this out, this is one
of the first pictures taking
now using this poking device,
and you can see it hits the moment
quite well.
And again, a little bit of magic.
Later, you end up with
this picture, which is actually one of my
all time favorites of the whole series.
And you can actually remove this poking
device quite easily.
So I didn't spend two hours removing
that. It was more like, I don't know, 15
minutes.
So now what you are going to see is.
Basically, you get the timing right after
a little bit of tweaking every time,
so, no, you can just go ahead by a 100
water balloons, fill them up and just go
ahead, pop them every time.
Because just because you get the timing
right doesn't mean you will get good
pictures. So there are still a lot of
random stuff going on where
the droplets are going, where the rubber
is ending up. All of this is still
random.
So you still want to take basically
a lot of pictures, but at least
the timing is now, right?
Almost every time.
So now you just keep going,
take 40 pictures, 100 pictures,
and then select the ones you like and and
post-process them.
So, yeah, here's the last one.
One of my favorites, because it reminds
me of a sudden eruption.
So whatever
you like, that's then basically
a matter of taste.
So coming
to the second set up, I want
to show this is about
exploding chalk.
I have also shown this
in the very beginning and
the basic technique that this uses is
mousetraps.
So here's a mousetrap.
Basically, the way it works, it's a
one of those deathtraps, actually.
So it has the spring-loaded bar,
it gets pulled over.
And this then holds in place
by this copper rod that you can see and
the copper rod slides under the
triggering mechanism.
So it keeps the bar from
you are basically snapping over
and you would place debate on the trigger
and then the mouse goes there.
It will move debate the the rod
will break free the Bava
snap and it will basically
kill the mouse.
Now, these are very good to
give a very fast and forceful
impact. So to kind of let high
speed stuff happen.
But the triggering mechanism
is not optimal.
So basically your your
zone where all your action is going on,
what will be in your frame is is to the
right, right where the trigger
is. So you have to trigger in the frame.
You need to somehow maybe attach
a threat to it to kind of trigger it from
far away. And all of this stuff will be
in your image giving you big problems
with post-processing.
So what you wanna do is you've
got the mousetrap and
the solution that I ended up was
looks like this.
So you basically bend the rod
into this s like shape
so you can put it on top and it basically
holds itself in place through
the mechanical forces
and.
Basically, you can slide this road off
to the top by maybe attaching a threat
to the small,
to the small hole on the top, and then
it will basically break free and
trigger the exposure.
So now you have all the triggering
mechanism out of frame.
You can just remove it.
And it's also a lot safer to start
because you don't need your fingers
or something else in the zone that
this bar is going to go.
Now, I took a hit with a mousetrap.
It's nothing that you find very long
about, but it's also not something you
really want to have.
So now he has
to set up again.
That's in my living
room. And it's basically an
improvised light tent
built inside of a chair.
So, again, the background and everything
which will be in the frame is
in black and all
the walls and the ceiling is covered
in white fabric.
The reason is the same as before to
get lots of light, to bounce back from
all direction to the scene and give you a
very even illumination.
So you can see the microcontroller there
and the left does lots of wiring going
on. And you can see that the trigger
mechanism on the right.
So there's this crocodile
clip, the white one, which basically
bites to the bar and is
duct taped to the floor.
So you're going to have a lot of duct
tape for this, by the way, and.
As soon as you release the mechanism,
uh, the crocodile clip will
rip off and this
will tell the microcontroller to fire.
So here is another wiring
diagram.
So I decided to put a five
volt signal on the white crocodile clip.
And
the other clip connects
to the input of the microcontroller
and why they are connected.
It will read the high input and as soon
as a disconnect descends,
input will get put down to ground over
our one, which results
in a falling edge on the microcontroller.
And that is what triggers the interrupt
and allows you to feel the flash.
So basically very
similar to last time and
not very complicated.
Now, before you smash chalk, which is
a very messy business, especially
if you decide to do it in your living
room,
I would advise you to start
easy.
So where we had
some bottle caps ready for various
reasons.
So, uh.
You can put some some
drops of water in there
and actually use this for, let's say,
the first 50 shots that you try
to understand, where are the variables
in this process?
So to make it more controlled,
to get the timing right every time,
but especially in this case, took
probably 100 pictures on its own.
And you don't want to smash 100 times.
Not a good idea.
So.
This works pretty well, it dries of
quickly, and it's not really much
cleaning work, and if you
are lucky, you may even get
quite, uh, quite a nice picture out
of it, like like this one.
And so finally, you get your timing
right.
You put the chalk in and
well, this happens.
So
a mouse trap
just doesn't cut it.
So you can see it
puts a little dent in there and some
small pieces fly off, but ultimately
not too exciting.
But as the old saying goes, when the
mouse trap is not strong enough,
you need a rat trap.
So.
So this is basically scared
up and
everything else is the same.
I did not take a hit to
my fingers with this, but
I wanted to see what it does to a metal
setting.
And after seeing
what it did, unfortunately, I don't
have a picture, but I'm fairly certain
it will break your fingers.
So please be careful if you try this.
Then I decided to to Tumut
the trap again, so you can
see it escaped
the escaped wrath again
to to kind of get the trigger away.
I also decided to to cover
the front part in
this black cardboard, which
you will see later. Why?
And you also want to strap this to
something heavy. So this is a left over
piece from my from my kitchen countertop.
So it's a really heavy piece of wood
because these things, well,
they tend to take off when they fire.
So maybe you have seen some of those slow
motion pictures of mousetraps firing
those things fly all over the place.
That is also what happens here.
So attached to something
heavy.
So obviously, those things have enough
power to obliterate chalk,
basically,
and you can also see
why I did this modifications to the
trap. So if you don't, you get this,
uh, this Brightwood in your
frame, which really is very distracting
for the eye.
And you can also see the trap
basically took off with the back to the
side of the frame, which makes it
very difficult to get the focus right
and also to get the framing right of
your picture. So if you
attach it to something, you will again
take a lot of randomness out of the whole
process, and that's what you want to do.
So now, after improving the process,
this is what you may get.
So at some point I started
playing around with was
putting several small pieces of colored
chalk together.
And I really liked, um,
where this is going, so.
Still improving the process.
This is basically the final
form, if you want, I don't know
how many of these towers I built, but,
um, it takes probably five or
six minutes.
So you're only able to bring this into
play when you got your process down,
because otherwise you would be dancing,
doing nothing but, um,
super gluing choc pieces together.
So that's
that's not so good.
So, yeah, then you just try
if you got your process done
and at some point.
You get this picture where everything
is looking pretty good
and then you just have to take it
to the gym.
And finally, after
a lot more post-processing, this
is what what I ended
up with.
Um.
Thank you.
So, yes, exploding rainbows,
so I hope that that gave you an idea
on.
And how you can go about building a set
and also how to to trigger the flash,
so that basically ends the tutorial part
and now for.
The last couple of minutes,
I want to talk a bit about the
requirements of Yogya to show you
that if you are a little bit into
photography, you probably already
have everything that you are going to
need.
So let's talk about cameras.
Um, your camera
needs to be digital,
so you really want to have
this this
feedback, especially when
when calibrating your parameters,
you don't want to wait a few days
for your film to come back
until you take the next change in, I
don't know, your flash delay.
So. However, of course, since the camera
is not doing anything except opening the
shutter, you can of course, put several
cameras there and one
of them can as well be a film camera.
So if you like film, you are not
a completely
you're not completely out of options.
Now, your camera needs to do
a long term exposure, so I recommend
five seconds or more.
This probably removes
lots of mobile phones.
I am honestly not sure if those phones
that can take long term
exposures. I know mine cannot,
but this is this is very practical
to give you some time to to start
the action.
I strongly recommend manual
focusing or at the very
least, you should be able
to set your camera, that it's not
focusing when you start the
exposure because you want to pre focus
excuse me, which you can do
using the autofocus, but
then you want to turn off the light
and then you start the exposure.
And if it tries to autofocus, it will
it will probably completely
get your focus wrong.
But actually I recommend manual focusing,
especially in the last steps, because,
as you know, you have a basically
depth of field.
And so the objects that
are in focus are in a certain
range, basically
starting a few centimeters away from your
camera and ending a little bit more.
And
you can basically focus predictively.
So maybe you want to make sure that.
The area of sharp objects is
towards your camera, so that's something
that during the high speed
start flying towards your camera
is still in focus.
But that's like advanced
stuff when you when you finally got
the basics covered and
talking about stuff flying at your
camera and
you want to have a long lens.
So I was using, uh,
100 millimeter lens because that's
the longest I got and also the
best.
If you have more, I recommend more
for two reasons.
If your lens is longer so
you can be further away from
your object and still get the same
size and having your expensive
camera further away from
splashing water or even worse, exploding
chalk is usually
a good idea.
And also, if you're using a
telephoto lens, you basically
have a narrower angle of view
and so basically you will get less
background into the picture,
whereas if you use a wide angle lens, you
have a lot of background in your picture.
And so you need to make all that
background look good, whereas with the
lens, it's just a very small area.
So it makes building your set a
lot easier.
All right, um.
Let's talk about Flash,
as I said earlier, you can
basically shop.
A wide area of letters from last
25 years
when the standardized Hotaru
came into existence.
There's a couple of flushers that use a
proprietary hot shower, you should make
sure to get one with a standard
one so you can you can be sure
that you have the accent contact at the
right place to use with the commonly
available adapters.
Otherwise, stuff may get a little
bit more expensive.
The flesh needs to have an excellent port
and they all have.
You can also go with studio flushers,
then you will already have the PC sync
port, which makes the wiring
a bit easier.
And it has also shown to be very
practical to shop for a flash
that actually supports different
power settings, because,
as I said earlier, this allows you
to set your effective exposure
time. So there is some some very
cheap flashes.
They don't have any controls except of an
on off switch.
So you plug them on.
They will always fire with full power,
which is probably not optimal.
You can start with that, but you
will lose a lot of control
over your process.
So some other stuff
that you may need, um, well,
a microcontroller.
So, for example, an auto,
you know, or whatever you have
lying around.
As I said, any microcontroller should
have to a digital Io's
and at least one interrupt.
Otherwise it is hardly a microcontroller.
Now, I recommend the tripod
to put your camera on,
maybe also a flash.
So if you do like photography
a little more seriously, you probably
already have one.
It doesn't need to be a fancy one.
So you don't need to
spend like a thousand euros on a tripod.
You can get a cheap one or even a used
one, um,
because the requirements are not very
high. So especially for stability
at long as long as your camera isn't
tipping over.
It probably works because 150
thousands of a second won't be much
movement in your tripod.
Um, yeah.
For the flash you can get really
creative. You can duct tape it to
something. You can put it on this small,
uh, Kuryla pots or
the Chinese copies of it,
which also work pretty well.
Um, I recommend getting some
black and white fabric
so you can use this a set
of fabric, molton
or something else.
I have some fabric which is black on one
side and white on the other, which kind
of saves on fabric.
I recommend having a stack of
cardboard also in the colors of
black and white.
They are super practical to build
like light formost to block of light
from areas where you don't want to have
it. And yeah, go to any
store that sells autist equipment,
you can get them for like ten cents
apiece. So not very
expensive, some
really, really entry level electronics.
So maybe it's altering.
Iren, some, some twiddles,
some players and maybe a few resistors
is really all you're going to need.
You can also very easily use
a breadboard for it.
It's almost perfect.
And duct tape, lots of duct
tape. So that's the most
important thing.
Um.
So that is some some
final tips, which also
is a little bit opinionated, but that's
how I.
That's the things that I find that work
best.
So before putting up
a very elaborate set up
and smashing towers
of chalk that require you like 10
minutes of building
a first start with something easy,
um, to basically learn the process
of how your mousetrap snaps, the delays
that you need to set.
There will be a lot of misfires there.
Um.
Really don't start to
complicated it, it will just slow you
down and frustrate you once you got your
process done.
Then please go crazy and make
it perfect, so.
Yes, you should expect
a lot of failures when doing this,
so you can probably expect to and a 100
pictures to be relatively decent
and you just need to keep going.
So there's lots of randomness in this
process. And if you want to get
a good picture out of it, you just need
to sample by taking a
lot of pictures and eventually being
lucky and getting a good one.
Now, what I also
think is very important is to
actually build your set to
HQ in post-processing and also
to prevent post-processing.
So as I said, if you have this
this Brightwood, for example, from The
Mousetrap in the pictures, not
only does it look very bad,
it also is very, very difficult to
post-process because it's right where the
action is. So removing this is
virtually impossible and it will give you
a lot of work, whereas if you cover
it with black
cardboard, it will basically start to
vanish as soon as you turn
up the contrast.
And the black cardboard can even
be used as a picture element,
which is not distracting to the eyes, but
just gives like
a nice natural framing to
the bottom part of the picture.
Um, you should make sure
to to clean
and really prepare the set after every
shot. So I actually used
a vacuum cleaner to to clean
up the chalk set up for every
after every shot.
Because if you don't do this, then small
pieces of chalk will be lying
around everywhere.
And to smash from
the rattrap is really, really strong
through all of these small particles will
fly up and give you kind of a
a mist in your in your image,
which destroys,
um, the cleanest.
And finally, if there is some
elements like the bars of the mousetrap
that you cannot really mask and you
cannot really prevent from getting in
your image, then you should just embrace
them. So make them
part of the image and don't try to
hide them like Hofstee, because
that is that is never going to look good.
So most important thing, of course, is
to have fun and enjoy doing this.
So here are some resources.
Um, again, the coat
on on GitHub,
um, and some reads
that I that I find interesting.
So the first thing is stroboscope.
It started basically from this
this blog stroboscope
and.
It became a little bit of a
movement in photography,
so it's show business, basically,
people using flares,
sometimes lots of flashes
in a creative way to get good
pictures. So you can find lots of
tutorials on how to use a flash
to give you good photographic lightning.
I learned a lot from them.
You can actually look up high
speed photography tutorials,
seriously put it like this on Google.
You'll find tons of results.
Um.
If you are more a friend of
books, one very
good read I had was the book
Light, Science and Magic, which is
basically a book about photographic
lightning.
So if you feel comfortable with
your camera, I
can heavily recommend it.
I am not associated with them,
um, just to make that clear.
But it's a really good read.
And you learn a lot about how lightning
works in the context of
photography.
So if you want to contact me, that's
my email address.
This is my Flickr account,
Pouilly.
I put lots of or actually not so
many, but all the pictures that I find we
are showing over the years, so it's not
just high speed stuff, but also.
Other studio pictures like the lamps that
we are there in the beginning and
since I used a lot of Creative
Commons pictures for this presentation,
I finally got around to change the
license to Creative Commons.
So if you want to use a picture, be
my guest.
So also for
a little less complicated
context as compared to email, I created
a Twitter account actually two days ago,
so I
will post a lot of these pictures over
the next few days and then.
Well, I see. If I like it or not.
So see where it goes from there.
So that's basically the end of my talk.
I would really love if any one
of you tries to please contact me through
any of this media and show me what
you did. I I like looking
at pictures almost as much as I like
taking them and.
I do have some ideas for.
High speed photography, which are
not really suitable for a living room,
so if you happen to live in Drayson and
have a room, that doesn't matter if it
gets a bit messier, um,
I would really like you to to contact
me and you may get a
print out of it. So thank you for your
attention and.
OK, thank you, Polygon, for this very
interesting talk.
Um, we still have quite a few minutes
for questions.
We have microphones in the room.
You can line up behind the microphones.
If you really have to leave the room,
please be quiet.
That means no talking.
Thank you.
And we're going to start with a question
from the Internet.
OK, there has been some discussion about
doing multiple, multiple photos, like a
series.
Do you think it is possible to do them
with the movie mode and open the shutter
or even using multiple cameras in a
flash setup with multiple flashes?
So the first answer is
we tried this using
the movie mode
and actually.
Set the flesh to kind of a stroke
mode.
So it basically fires 30
flashes a second, so my flash
can do that, but unfortunately,
even if you do the movie mode.
The picture that is taken from the image
there is small breaks in between,
so we never really got it to
a point where the whole picture
was illuminated by each flash.
So basically, you you get
lots of missing pictures or
partial exposures,
probably because the way the flash
is read out by the camera
and on the other hand,
30 frames per second, it's
not really much. So that is, uh.
Quite a lot of milliseconds between each
frame, and so you probably have one
frame, which is good, and
the rest of the frames, which will be
very boring. So I try
to in the movie and it didn't
work to put it simply, and to build
multi cameras and multi flash.
Do you think there's a way to get that
work?
If you want to use multiple flushers,
you can try it.
Um, you should
probably use flashes
of the same build, probably ideally
even of the same charge.
So you have exactly the same firing
delay.
Then you can probably use several flashes
if you use flashes from different
manufacturers.
I tried this and you will get double
exposures. So you see there
is basically two images now, multiple
cameras. No problem.
You could point 10 cameras at it.
As long as they are not in the way of
each other, you can use as many of them
as you want. So if any one of you has
like 20 cameras to spare and
wants to build a ring to kind of make a
Matrix style animation, it would be
really cool.
Microphone one, please.
Um, I have a remark about the flashes,
if you use studio flashes, they have a
quite long flash tube and
the flash duration or
upper end side German
might then be a problem for high speed
photography.
It's when you take a pictures of your
model and start throwing water or
colorful powder on your model and
you want to have it flying,
then you run into problems
with cheap flashes.
Let's say everything under 1000
euros per flash is then a problem
with a high speed movement.
So if you do use studio flashes, yes,
if you use studio flash as a small
type of camera, flashes generally don't
have that problem.
OK, very good to know.
So don't use studio flushers use
on camera flash. Thank you.
I didn't try them yet.
Microphone to please
on the on these cameras, there's like
these wire shutters, have you
tried firing the camera, using the
microchip and
not yet because it
would be an accurate.
So.
If you have a DSL or they have to
put up tomorrow, they have to
prepare the shot like, I don't know,
clear out the sensor or start to shutter,
all of this takes probably
several tens of milliseconds of time.
And since the trigger pulse only comes
like really right before,
you also need to have your exposure
already.
Um, this is generally
too long, so I didn't even try
it. There is some tutorials
on the Internet for
for other scenarios.
So let's say if you photograph a
fountain, that doesn't really matter
when you take the picture, just that you
freeze the action, then you you
can probably use
this cable, this cable trigger.
Yeah.
OK, do we have another question from the
Internet?
Um, yes,
um, there was a question about, um,
what lengths you are using and what if.
No and did you have any problem with
focusing?
Um, so the lens I was using
was a Tokino
100. Mm.
Microland with a
I think it's an F 2.8, but that
doesn't really matter because you want to
close your aperture.
I think I closed it down to
f 16 or something.
So right before you run into problems
with uh, with uh
basically deflection because of a two
small aperture.
And yes, focusing is a huge problem
because those objects are very small.
So this is not very different from a
macro shot.
And since you don't really know where
your stuff ends up, um, during
your high speed action, um,
it's a huge source of frustration when
you get the perfect shot.
But then your main part is slightly
out of focus.
So focusing you will spend
a lot of time on doing,
uh, when you try this
and you will also have lots of failures
because of focusing.
Microphone three, please.
Hi, thanks for the wonderful
presentation.
How did you actually create the smoke
inside lightbulbs?
Did you run a lot of Gurren through
the filament?
Yes.
So maybe
as you can see it here, there's light
coming out of the top.
So the idea here is I used
a kind of, um,
diamond to a like a dentist has
to put two bulbs, add two holes
in the.
In the glass of the light, and then
you blow in some oxygen to get out of the
protective gas, and then you just attach
it to a normal outlet and
that's going to happen.
OK, thank you.
I'll try it.
And microphone one, hi.
Have you ever tried to shoot with
a crossbow in a complete
darkness?
No, I didn't, but if I try, I
would probably put it on something
that takes aming out of the picture
and I wouldn't hold the apple with my
hands.
Um, another question from
the Internet, um, yes,
um, there is a question about
the way you are triggering.
You can either sense the moment the trap
goes off and release the trap
trap at a specific time for the mouse
trap.
Um, so do you think there's any merit in
timing the process rather than sending
a sensing when the trap releases?
Um, I found that generally to work
better if
you actually get
your.
Interrupt before the
actual action happens, so when
the bar breaks loose, of
course, you should get, um,
you should get your signal, then it's
already quite deterministic
when the actual action will happen so
that you can configure the delay.
And there is some idea.
So, for example, when you have and you're
firing, let's say, a crossbow or a bullet
at something, you can also put
the mechanism behind it maybe to,
uh, aluminum foil, which gets smashed
together by the impacting bullet.
But then you really you're basically
too late. So then you don't have control.
You basically want to instantly
when the interrupt comes, you want to
fire the flash so
you lose control. So I found it to work
much better when, um.
When I did have the information before,
so I think I even tried to trigger
on the bar smashing down on something,
because obviously you can pull the
trigger there as well.
But it didn't work that good because you
have to small 100 microsecond delay
before the flash fires and
that can actually be too much.
So I find it to work better, getting
to know before finding
out a good delay and and then
firing the flash based on that.
OK, we have time for one more
short question, so microphone two,
please.
How do you how do you complete
darkness room?
Well, take a picture at night,
cover the windows and turn off the
lights.
So,
OK, thank you.
Once again, putting on and please give
them a big round of applause.