Hello there. Now you may be wondering
what is so fast about a camera.
Well I'll show you.
When you take a picture
with a regular viewfinder camera,
you're not actually looking down
the same lens
that's taking the picture,
you're looking down
a separate viewfinder lens.
And in some situations,
that gives you
a slight difference in perspective,
'cause it's only an approximation,
of what your picture is gonna be.
Now a way around
that is by using an SLR camera,
which stands for single lens reflex.
That's pretty much
exactly what it is.
There's only one lens,
there's no separate viewfinder lens.
Now that requires
a little bit of cleverness
behind the lens,
there's actually a mirror placed at 45 degrees
that blocks the sensor,
which means you can look
through the viewfinder down
and through the exact lens
it's gonna take the picture.
So that leads us on to the very first part.
When you take a picture
you'll hear this sound,
didn't sound like much,
but actually quite
a lot just happen there.
And you'll notice
that in the viewfinder,
your vision was blocked
for a split second.
So the only way we're gonna see
what actually happens
is by taking off the lens,
zooming the Phantom in
and filming this
at a ridiculously high frame rate.
We'll start with a 30th of a second.
Now you're looking at the mirror
which is in front of the shutter.
When I press down the button,
the mirror flips up out
of the way
and temporarily blocks the viewfinder,
then the shutter comes down, whoosh.
Now light is exposing on the sensor
and then the shutter closes again,
followed by the mirror coming back down.
So you can see
through the viewfinder again.
As you can see from that clip,
this camera has a mechanical shutter
that moves out of the way
and allows light to hit the sensor.
Very fundamental part of photography
is degeneration of your exposure
has very different effects on the image,
and you can control
that with the shutter speed.
For example, a relatively long exposure
of say two seconds,
will give you a bright image
but anything that moved
within those two seconds,
will have a trail
of motion blur behind it.
So not ideal for filming a fast moving subject.
For a very fast moving subject,
you would want
a much shorter shutter duration.
The fastest this camera will do
it is in 8,000th of a second,
which looks like this.
So now what we'll do
is we'll use the Phantom
to film different shutter speeds
of the camera
and see how they will compare
to each other in slow motion.
Honestly, these are probably
gonna look identical in real time,
but we'll definitely be able
to see the difference in slow mo.
So start with 500th of a second.
1,000th of a second.
A 2,000th of a second.
4,000th of a second.
and 8,000th of a second.
Let's have a look
at the four fastest ones
side by side
just to see the comparison.
This kind of stuff is fascinating to me.
It makes me wonder how many people,
take for granted
what's happening inside the camera
when I take a picture.
The fact that the shutter
is made of two clusters of metal blades
that at their shortest duration
are moving right next to each other
allowing just the smallest slit
of light to hit the sensor.
This is also a great visual representation
of why you need so much light
for a high shutter speed shot.
Because the amount of time
the light is hitting the sensor is so short,
you end up with a much darker image.
There are many types of shutter
that a camera can have.
This is a mechanical shutter,
but there's also an electronic shutter
which doesn't have any moving parts.
In video mode,
this will actually use an electronic shutter.
It basically takes an image
30 times every second
without covering the sensor.
This camera shutter
is also a rolling shutter,
which is the opposite
of a global shutter.
And what that means is,
is that it doesn't actually
take the whole image
at the same time,
you may have noticed from the slow mo,
that the image is taken
from the top to the bottom
of the sensor.
That basically means
that whenever you take a picture,
the top of the picture
is actually older
than the bottom
by a fraction of a second.
And technically that statement
should be flipped as everything traveling
through the lens,
is actually upside down
by the time it gets to the sensor.
The electronic shutter on this camera
when it's in video mode works
in the exact same way.
It takes each line of pixels
from top to bottom
because it doesn't have the power
to take the whole image at once.
And this can lead
to some interesting artifacts
when filming certain subjects.
You may remember this video
from a few years ago,
I was blasting Dan in the face with a cork.
And when I was editing the video,
I noticed something really weird
in the Canon footage.
On this one frame of video,
the cork is suspended in the air
but the shadow of the cork
has already hit him in the face.
Luckily we had the Phantom
right by its side
so we can analyze exactly
what happened with the canon there.
So imagine the color going down the screen,
as the canon acquiring
each frame of its video.
Nothing happening in this frame,
watch this one though.
As it gets down to the cork firing
then hits the shadow.
And that explains
why there are two different moments
in time at different heights
in the same frame.
Almost any camera you use
these days to shoot video,
will have a rolling shutter
and that's due to the frequency
of CMOS sensors being used in DSLRs
and pretty much every smartphone.
And you can test this out
by pointing your camera outside
the window of a moving car,
and just filming trees and poles
that go by.
You'll notice that everything that's vertical,
will be slightly skewed diagonally
'cause the object is moving
as it's being scanned from top to bottom
or bottom to top.
There's definitely pros and cons
to both the global
and the rolling shutter.
For example, the Phantom flex
has a global shutter
which makes it much better
for the scientific analysis of shots,
as every moment in the frame
was taken at the exact same time.
A phantom flex 4k has a rolling shutter,
but it's typically used on movies
and TV where it seems
to be quite natural
for the human eye to look at.
Before I end this video,
I feel like I should say a few words
about the state of this camera.
It's a Canon 7D,
I bought it right before
I started the Slow Mo Guys,
and I've used it
in every single episode
to film the real time segments.
And it's taken an absolute pounding.
It's been in the splash zone a few times.
Oh, it's right on the lens.
It's a splurge
It's fallen over.
There's a screw loose,
I've just noticed,
but I refuse to replace it
because it still works.
So I hope you enjoyed that video,
maybe you learned something,
be sure to follow me on Twitter.
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Thanks for watching.