okay this is super weird because I can't see, you guys... but hello YouTube!
I'm Kurtis Baute and this is the Scope of Science and I just built
I built a digital camera. Okay wait a second, we're gonna start from the very
beginning. You see, this isn't really a video about the camera that I built but
it's about how I built it. People often ask how the eye, in all its complexity,
could have possibly evolved, and I actually think it's a great example of
evolution. Now since the eye is actually a lot like
camera - well the camera is a lot like an eye - I've decided to evolve a digital
camera, one step at a time, so that at each step it still worked. So this is
that process. I start by making something that can sense light it's a photocell
and I'm going to make mine using a copper penny.
You see metals like copper give off electrons when they're exposed to light
and by adding some heat and some saltwater to a plate of copper I can
actually make that effect big enough that I can measure it. Animals also see
light by using chemistry and electrical charges just instead of copper its
proteins and instead of wires it's neurons. Now I can take the number value
that I get and represent it as a degree of brightness a lower number is darker
and a higher number is brighter. Now to make a camera I'm gonna need a lot of
these but since I don't have 2.8 billion years to evolve the camera (and that's
how long it took for life to evolve vision) I'm just gonna take a couple
short cuts and I'm gonna order a bunch off of Amazon. This photocell is more
compact than my penny but if I connect it to my Arduino brain-computer thing I
can use it in pretty much the same way. If I put a bunch of these photocells
together I get a sensor and now I can measure light even better and now I can
finally start to tell if maybe there's a predator swimming above me and if it's
casting a shadow onto me. That's really important information to have! This is
what life might look like for a Hydra: they can see light and dark but that's
about it. Now I'm going to build a wall up around my sensors so that light
entering one side casts a shadow on some of my photo cells. If light enters from
the left side of my sensor it casts light on the right side, if it enters
from the top it casts light on the bottom. I can now use my camera to sense
directionality it can see if light is coming from over there or if there is a
predator coming at me from behind this is what life might look like for
flatworms their eyes are just little sensors in a cup the bigger this wall
gets the smaller the hole becomes and the more directionality I can see
eventually I can close that hole almost all the way until it's just a pinhole - we
call that a pinhole camera. And it's not very sensitive so I need to use a lot of
really bright lights so that it can receive an image and since I'm using so
many bright lights I have to wear these glasses to protect my eyes because it's
blinding otherwise so I can't really see you guys. But I built this digital camera
using 16 photo cells and a pinhole box and the image you see from it is
currently in black and white and it's just 16 pixels so it's pretty extremely
low resolution but hopefully you can make out my selfie. Hi! And the image you
see from it is upside down and backwards because of how light goes through this
hole in the front of this camera. The image is upside down and backwards
because, remember if light enters from the left side it shows up on the right
and if it enters from the top it shows up on the bottom. I can use computer
software to rotate and flip that image. In life that software is stored in
brains. It would be good if we had a colour image and we can do that with a
little grade school math and physics. All of the light we see is
made of just three primary colours: red, green, and blue. Mix them together and you
get purple, or well, I mean, you get the idea. If we specialize our photocells so
that each one only detects one colour; say we cover it with a red filter so that
only red light gets onto that one... we can see how much red is in the image, or how
much blue is in the image, or how much green, too. The thing is that each
photocell needs a value for each colour purple is lots of red, lots of blue, but no green.
But we can use the power of averages for this this photo cell senses red and it
uses its neighbour to figure out how much green and blue is nearby. Computing that
we get: purple. our eyes actually work like this,
they have three photo cells called rods ones four red ones four green and one is
for blue. Now my camera it can see colour so let's take a look out my window it's
a little pixelated but... I mean okay, it's it's really... it's really pixelated. After
spending a lot of hours trying to upgrade my camera from sixteen pixels to
81 pixels... after all that, finally...
I gave up when I
realized that this was the best possible image I could get from an 81 pixel
camera in the best-case scenario. And yes it's cool but it's just not good enough
because I want to show you how lenses work and I can't do that with this level
of resolution. So, I just upgraded from 16 pixels to over 2 million pixels using
one of the camera bodies that I already owned, and this is the image you get with
that and it's blurry because I still haven't added a lens to it. This is still
just a pinhole camera it's a piece of cardboard with a pinhole in it so the
light goes directly onto the sensor. This is the world through the pinhole eyes of
the Nautilus: it's dark and blurry, but there are images and colour. For the next
step we're going to add a very simple lens... Behold!
The water droplet. Yes, just a single droplet of water can act as a magnifying
glass, and this is something that you can try at your own risk on your smartphone.
It will act as a macro lens making very tiny things very large to your sensor so
that you can zoom into tiny little things like the Canadian flag on the
sleeve of the astronaut on the five-dollar Canadian bill. Lots of snails
have simple lens eyes like this. Now that lens is still pretty crude so
we're gonna bring it up to the next level. This crazy-looking image that's
kind of blown out on the sides is what you get if you just use a magnifying
glass in front of the pinhole. It's better than nothing but it's still kind
of distorted on the outside, but hopefully this gives you an idea of the
focus that a piece of glass or our droplet of water can give you in making
an image. I finally look like a real person! Okay, a weird person but I thats
how I normally am. Now there are more tweaks you could do in evolving a camera,
like being able to change the size of the pinhole, or change the distance
between the pinhole and the lens. All of those things can change and improve the
image that you get but I think by now you should get the idea of how a camera
works and how a camera or an eye could evolve. Something really cool happened
while I was working on this project but before I get into that if you feel like
you've learned something so far please consider subscribing to this channel
you'll SEE the button for it below... if bad puns don't make you subscribe what
will!? ok.. ok. So while this project evolved the code that I was writing got messier
and messier because I kept adding new code but since it usually wasn't worth
my time to delete the old code that I was no longer using it kind of just
became clutter and just built up. Now, what's awesome about that is that that's
what actually happens in evolution. Most of our DNA doesn't actually do anything
anymore - it used to, but it no longer has a function, and it just kind of stuck
around. Scientists call it 'junk DNA' and it makes up most
our DNA! Evolution doesn't solve things in the best possible way, it just solves
things using whatever way is good enough. That's why our eyes have a blind spot.
You see, the photocells in our eyes are actually pointing the wrong way they're
pointing away from light so there's actually a bundle of nerves where there
should be photocells if you want to find your blind spot, I left instructions
in a link in the description. If you liked this video you can like this video
and if you want to learn more about how evolution works I recommend the book The
Selfish Gene by Richard Dawkins. It's actually the reason that I started to
take science classes in the first place. The 40th anniversary of the book just
came out and I can tell you it stands the test of time, it is a true classic.
You can buy that book using the link in the description and that link will also
help support this channel the Scope of Science. I also put some links to the
camera gear that I use to film the camera that I made it was meta, right?
Anyways thanks so much for watching!