1 00:00:00,120 --> 00:00:01,720 Hello there, my name's Gavin, 2 00:00:01,720 --> 00:00:03,439 and welcome to this episode of The Slow Mo Guys, 3 00:00:03,439 --> 00:00:06,000 very oddly presented from my living room. 4 00:00:06,000 --> 00:00:07,860 A while ago, I made a video called 5 00:00:07,860 --> 00:00:09,439 how a camera works in slow-mo, 6 00:00:09,439 --> 00:00:11,039 and the response was great. 7 00:00:11,039 --> 00:00:13,859 So I thought a good natural progression to that video 8 00:00:13,859 --> 00:00:16,039 would be how a TV works in slow-mo. 9 00:00:16,039 --> 00:00:18,920 This is an 85-inch LCD TV, 10 00:00:18,920 --> 00:00:20,600 and whenever I'm playing something on it 11 00:00:20,600 --> 00:00:22,000 or watching something on it, 12 00:00:22,000 --> 00:00:25,359 my eyes and brain are being misled and tricked, 13 00:00:25,359 --> 00:00:28,120 giving me the illusion of watching a moving object, 14 00:00:28,120 --> 00:00:31,399 when in fact, I'm just watching several still images 15 00:00:31,399 --> 00:00:33,460 just shown to me very, very fast. 16 00:00:33,460 --> 00:00:34,539 If I'm watching a film, 17 00:00:34,539 --> 00:00:37,600 I'm being shown 24 images every second. 18 00:00:37,600 --> 00:00:38,640 And to my eyes, 19 00:00:38,640 --> 00:00:40,299 that looks like I'm looking at a moving object, 20 00:00:40,299 --> 00:00:43,740 when in fact, I'm looking at 24 individual pictures. 21 00:00:43,740 --> 00:00:44,700 If I'm playing a game, 22 00:00:44,700 --> 00:00:48,640 it's the same except maybe 30 to 60 frames a second. 23 00:00:48,640 --> 00:00:50,719 And if I'm on a PC, it could be hundreds. 24 00:00:50,719 --> 00:00:51,560 PC master race. 25 00:00:51,560 --> 00:00:54,000 But a TV like this is actually incapable 26 00:00:54,000 --> 00:00:55,479 of showing you one image 27 00:00:55,479 --> 00:00:57,840 and then a 24th of a second later, 28 00:00:57,840 --> 00:00:59,820 just switching all at once to the next image. 29 00:00:59,820 --> 00:01:01,640 And to illustrate this next point, 30 00:01:01,640 --> 00:01:06,640 I'm gonna use a very old and very crap CRT TV. 31 00:01:06,819 --> 00:01:08,579 That stands for cathode ray tube. 32 00:01:08,579 --> 00:01:10,560 If you've ever seen one of these filmed, 33 00:01:10,560 --> 00:01:12,819 you may notice that it looks slightly different 34 00:01:12,819 --> 00:01:14,900 on camera than it does to your eye. 35 00:01:16,439 --> 00:01:17,400 Look at that. 36 00:01:17,400 --> 00:01:19,560 The reason it looks like this is because 37 00:01:19,560 --> 00:01:22,959 the shutter speed of this camera is out of sync 38 00:01:22,959 --> 00:01:25,359 with the refresh rate of this screen. 39 00:01:25,359 --> 00:01:27,560 The frame is constructed from the top 40 00:01:27,560 --> 00:01:30,180 to the bottom multiple times per second. 41 00:01:30,180 --> 00:01:32,180 That's 60 times in the US, 60 hertz. 42 00:01:32,180 --> 00:01:34,040 I've prepared for you some high speed footage 43 00:01:34,040 --> 00:01:36,620 that I shot a long time ago on the V2511 44 00:01:36,620 --> 00:01:40,219 of this screen and this screen and some others. 45 00:01:40,219 --> 00:01:42,379 A lot of it is Dan playing Super Mario 46 00:01:42,379 --> 00:01:44,319 on the NES extremely badly. 47 00:01:44,319 --> 00:01:46,340 Here's the TV and the cat played back at 25. 48 00:01:46,340 --> 00:01:48,900 This is how it would be perceived in real time. 49 00:01:48,900 --> 00:01:50,579 And now at 1600 frames a second, 50 00:01:50,579 --> 00:01:52,099 you can actually see the scan line 51 00:01:52,099 --> 00:01:53,719 moving from the top to the bottom. 52 00:01:53,719 --> 00:01:56,019 You'll notice that on a CRT screen, 53 00:01:56,019 --> 00:01:59,019 It's only the active line of pixels that's bright 54 00:01:59,019 --> 00:02:01,260 and your persistence of vision will actually build that 55 00:02:01,260 --> 00:02:02,620 into a complete image. 56 00:02:03,599 --> 00:02:05,159 It's messing with my eyes, this. 57 00:02:06,780 --> 00:02:13,949 Triff, it's like a dance floor. 58 00:02:13,949 --> 00:02:19,599 Oh, didn't even make it past the first guy. 59 00:02:19,599 --> 00:02:22,759 Slowed all the way down to 2,500 frames a second, 60 00:02:22,759 --> 00:02:25,900 you can now differentiate each individual frame 61 00:02:25,900 --> 00:02:33,379 being built from top to bottom. 62 00:02:33,379 --> 00:02:36,139 It takes an extremely fast camera to see that each frame 63 00:02:36,139 --> 00:02:38,840 is built line by line from top to bottom. 64 00:02:38,840 --> 00:02:41,520 But it takes an even faster camera 65 00:02:41,520 --> 00:02:45,319 to see that each line is drawn from left to right. 66 00:02:45,319 --> 00:02:47,819 Slowed down to 28,500 frames a second. 67 00:02:47,819 --> 00:02:49,259 We're now seeing glimpses of that, 68 00:02:49,259 --> 00:02:51,300 but we do need to go even slower. 69 00:02:52,259 --> 00:02:55,759 This is now 118,000 frames a second. 70 00:02:55,759 --> 00:02:57,460 I'm gonna put the stats up for you here 71 00:02:57,460 --> 00:02:59,960 so you can see the actual amount of time that it took. 72 00:02:59,960 --> 00:03:02,300 And you can see now that the line is being drawn 73 00:03:02,300 --> 00:03:04,419 from left to right on the screen. 74 00:03:04,419 --> 00:03:07,500 Now at 146,000 frames a second. 75 00:03:07,500 --> 00:03:10,560 To gain perspective on just how slow this actually is, 76 00:03:10,560 --> 00:03:13,039 you can see the exact time I shot this. 77 00:03:13,039 --> 00:03:15,219 So this is hours, it was just past midnight, 78 00:03:15,219 --> 00:03:18,099 23 minutes, 41 seconds. 79 00:03:18,099 --> 00:03:21,060 This is a tenth of a second, a hundredth of a second, 80 00:03:21,060 --> 00:03:23,939 one thousandth of a second, or a millisecond. 81 00:03:23,939 --> 00:03:26,580 And then over here, you've got a 10,000th of a second, 82 00:03:26,580 --> 00:03:28,419 a hundred thousandth of a second, 83 00:03:28,419 --> 00:03:31,240 and this unit here is the millionth of a second, 84 00:03:31,240 --> 00:03:33,099 or a microsecond. 85 00:03:33,099 --> 00:03:36,759 We are now at 380,000 frames a second 86 00:03:36,759 --> 00:03:37,919 as our recording frame rate. 87 00:03:37,919 --> 00:03:40,400 That is the highest frame rate we've ever shot 88 00:03:40,400 --> 00:03:41,680 so far on this channel. 89 00:03:41,680 --> 00:03:44,580 And using this information, here's a little bonus fact. 90 00:03:44,580 --> 00:03:48,419 A CRT screen can draw Mario's mustache 91 00:03:48,419 --> 00:03:53,319 in less than a 380,000th of a second. 92 00:03:53,319 --> 00:03:56,060 That is some seriously fast spatial here. 93 00:03:56,060 --> 00:03:57,419 And if you're wondering why this footage 94 00:03:57,419 --> 00:03:59,759 looks extremely mucky and blurry, 95 00:03:59,759 --> 00:04:03,400 is because the resolution is only 256 by 128, 96 00:04:03,400 --> 00:04:06,580 which plonked into a 4K frame is this big. 97 00:04:07,979 --> 00:04:10,620 That CRT screen is standard def. 98 00:04:10,620 --> 00:04:12,759 This is a 4K screen, 99 00:04:12,759 --> 00:04:17,639 which means it's 3840 by 2160 pixels. 100 00:04:17,639 --> 00:04:19,379 That's over 8 million pixels. 101 00:04:19,379 --> 00:04:23,420 So think of the processing power that this TV has to have 102 00:04:23,420 --> 00:04:27,300 to update an image that big, that many times every second. 103 00:04:27,300 --> 00:04:29,500 The first thing you'll notice about a modern LCD screen 104 00:04:29,500 --> 00:04:31,819 is that it's not only the active line of pixels 105 00:04:31,819 --> 00:04:34,420 that retains brightness, it's the entire image. 106 00:04:34,420 --> 00:04:36,339 So you can actually see the full image 107 00:04:36,339 --> 00:04:38,319 as each scan line passes down the screen. 108 00:04:38,319 --> 00:04:42,399 This is every frame of the startup sequence on an Xbox One. 109 00:04:51,370 --> 00:04:53,250 I also recorded myself playing a game of Halo. 110 00:04:53,250 --> 00:04:55,389 Nothing will make you feel worse about your performance 111 00:04:55,389 --> 00:04:57,850 than watching your lousy aim in slow-mo. 112 00:04:57,850 --> 00:04:58,769 Look at that. 113 00:04:58,769 --> 00:05:00,470 It's crazy to think that when you're playing Halo, 114 00:05:00,470 --> 00:05:03,050 this is actually what is happening on your TV. 115 00:05:03,050 --> 00:05:04,430 If only you could see at this speed, 116 00:05:04,430 --> 00:05:06,550 your aim would be incredible. 117 00:05:06,550 --> 00:05:08,129 It honestly makes me feel bad 118 00:05:08,129 --> 00:05:10,029 when I fall asleep watching TV, 119 00:05:10,029 --> 00:05:12,990 knowing that this TV is doing all this intensive work, 120 00:05:12,990 --> 00:05:17,610 changing literally tens of millions of pixels every second, 121 00:05:17,610 --> 00:05:19,029 and there's no one there watching it. 122 00:05:19,029 --> 00:05:21,810 Here's a fun fact, the same applies to an iPhone, 123 00:05:21,810 --> 00:05:24,350 except it's in portrait mode. 124 00:05:24,350 --> 00:05:27,009 So if you're watching a video in landscape mode 125 00:05:27,009 --> 00:05:29,310 on your iPhone, you're actually getting updates 126 00:05:29,310 --> 00:05:30,990 from left to right, or right to left, 127 00:05:30,990 --> 00:05:33,029 depending on which way you flipped it. 128 00:05:33,029 --> 00:05:34,670 And that just proved to me that you can't see 129 00:05:34,670 --> 00:05:36,550 the refresh direction with your naked eye. 130 00:05:36,550 --> 00:05:37,529 Because I had no idea, 131 00:05:37,529 --> 00:05:39,910 whenever I was watching a YouTube video on my iPhone, 132 00:05:39,910 --> 00:05:40,930 that the screen was updating 133 00:05:40,930 --> 00:05:42,529 in a completely different direction. 134 00:05:42,529 --> 00:05:44,589 I'm not sure if this is the case for all smartphones, 135 00:05:44,589 --> 00:05:46,829 but it's certainly the case on an iPhone 7 Plus, 136 00:05:46,829 --> 00:05:48,110 which is what I filmed this on. 137 00:05:48,110 --> 00:05:49,990 So we've talked about one illusion of TVs, 138 00:05:49,990 --> 00:05:51,370 the illusion of movement. 139 00:05:51,370 --> 00:05:53,250 The second illusion I wanna talk about 140 00:05:53,250 --> 00:05:54,569 is the illusion of color. 141 00:05:54,569 --> 00:05:57,250 For this next part, I'm gonna need a second camera. 142 00:05:57,250 --> 00:05:58,329 Here's one. 143 00:05:58,329 --> 00:06:00,050 That's you, I love you. 144 00:06:00,050 --> 00:06:03,209 So, in order to film this screen extremely close, 145 00:06:03,209 --> 00:06:06,269 I have to set my focus at the minimum possible distance. 146 00:06:06,269 --> 00:06:08,189 So it's sort of like right here now. 147 00:06:08,189 --> 00:06:09,949 Set to my minimum focus. 148 00:06:09,949 --> 00:06:12,769 As I slowly move towards the screen, it becomes sharper. 149 00:06:12,769 --> 00:06:14,209 And you will then at the last minute 150 00:06:14,209 --> 00:06:16,670 see a very odd looking pattern. 151 00:06:18,230 --> 00:06:19,769 And what you're seeing there 152 00:06:19,769 --> 00:06:22,829 is an effect caused by the camera, this camera, 153 00:06:22,829 --> 00:06:25,350 trying to resolve individual pixels 154 00:06:25,350 --> 00:06:27,990 on the surface of this screen. 155 00:06:27,990 --> 00:06:31,389 As I push further forward, the effect disappears 156 00:06:31,389 --> 00:06:32,889 and everything goes out of focus. 157 00:06:32,889 --> 00:06:34,790 That's because I'm now beyond 158 00:06:34,790 --> 00:06:36,730 the minimum focal distance of this lens, 159 00:06:36,730 --> 00:06:39,050 which is about, well, it's about there. 160 00:06:40,350 --> 00:06:41,509 Not close enough. 161 00:06:41,509 --> 00:06:46,699 In order to get closer, I'm gonna need a macro lens. 162 00:06:46,699 --> 00:06:47,839 Here's one. 163 00:06:47,839 --> 00:06:49,879 As I approach the white 164 00:06:49,879 --> 00:06:54,040 and everything starts to become in focus, 165 00:06:54,040 --> 00:06:56,959 you can see that white isn't so white anymore. 166 00:06:56,959 --> 00:07:00,079 It looks like I have to go closer even than that. 167 00:07:00,079 --> 00:07:02,800 Thankfully, I can go all the way 168 00:07:02,800 --> 00:07:05,259 to five times magnification. 169 00:07:05,259 --> 00:07:06,379 Now, one thing from this point, 170 00:07:06,379 --> 00:07:08,079 I am definitely gonna need a tripod 171 00:07:08,079 --> 00:07:10,959 because there's no way my arms are sturdy enough 172 00:07:10,959 --> 00:07:13,279 to hold this in place, but I'll just ease it in 173 00:07:13,279 --> 00:07:15,319 just to show you the level of magnification 174 00:07:15,319 --> 00:07:19,370 we're talking about now. 175 00:07:21,790 --> 00:07:24,689 Well, it's close, it's a different story altogether. 176 00:07:24,689 --> 00:07:25,810 I'm gonna get a tripod. 177 00:07:25,810 --> 00:07:26,649 Here's one. 178 00:07:28,290 --> 00:07:29,490 What a mission this is. 179 00:07:29,490 --> 00:07:31,250 All right, let's see what we can do here. 180 00:07:31,250 --> 00:07:33,209 We're so close up right now 181 00:07:33,209 --> 00:07:35,069 that I can actually disturb this image 182 00:07:35,069 --> 00:07:39,279 by blowing on the lens. 183 00:07:39,279 --> 00:07:41,639 We're now looking at the sub-pixel level. 184 00:07:41,639 --> 00:07:44,639 A pixel is made up of three sub-pixels, 185 00:07:44,639 --> 00:07:46,560 red, green, and blue, RGB. 186 00:07:46,560 --> 00:07:48,019 You may have heard that before. 187 00:07:48,019 --> 00:07:51,540 And this creates the illusion of different colors. 188 00:07:51,540 --> 00:07:54,519 By dimming and brightening different sub-pixels 189 00:07:54,519 --> 00:07:56,180 to different intensities, 190 00:07:56,180 --> 00:07:58,480 this screen can create the illusion 191 00:07:58,480 --> 00:08:01,240 of literally millions of different colors. 192 00:08:01,240 --> 00:08:04,660 When all three are lit to full brightness, you get white. 193 00:08:04,660 --> 00:08:05,660 When all three dim, 194 00:08:05,660 --> 00:08:07,639 you go through gray all the way down to black. 195 00:08:07,639 --> 00:08:10,680 So if green dims away and red and blue are still lit, 196 00:08:10,680 --> 00:08:13,019 then you go into magenta, purple, that sort of area. 197 00:08:13,019 --> 00:08:14,459 And that's how the colors are made. 198 00:08:14,459 --> 00:08:18,980 So every time on your TV, you're looking at a white image, 199 00:08:18,980 --> 00:08:23,939 you're looking at tons of blue, green, and red lights. 200 00:08:23,939 --> 00:08:27,939 They're just so small, they look like white to your eye. 201 00:08:27,939 --> 00:08:30,040 Before you get white, red, green, and blue 202 00:08:30,040 --> 00:08:32,779 blurs into yellow, cyan, and magenta. 203 00:08:32,779 --> 00:08:33,620 And that's what happens here 204 00:08:33,620 --> 00:08:38,279 when I move the screen slightly out of focus. 205 00:08:38,279 --> 00:08:40,860 This is too close to watch a Slow Mo Guys video. 206 00:08:41,820 --> 00:08:42,720 I might vomit. 207 00:08:44,039 --> 00:08:48,299 It's the same situation, just entire blocks, 208 00:08:48,299 --> 00:08:49,279 and they're bigger. 209 00:08:50,600 --> 00:08:53,539 As I mentioned before, this is a 4K LCD screen, 210 00:08:53,539 --> 00:08:57,879 which a while back were typically lit by CCFLs, 211 00:08:57,879 --> 00:09:00,679 or a cold cathode fluorescent lamp, 212 00:09:00,679 --> 00:09:05,000 which means the entire panel is backlit by fluorescent tubes. 213 00:09:05,000 --> 00:09:08,759 Nowadays, they are backlit by LEDs. 214 00:09:08,759 --> 00:09:12,539 This is why this would actually be marketed as an LED TV. 215 00:09:12,539 --> 00:09:15,559 The benefit of LED screens over CCFL screens 216 00:09:15,559 --> 00:09:17,259 is that they're a lot thinner. 217 00:09:17,259 --> 00:09:20,039 Now I'm gonna point it at where some black text is. 218 00:09:20,039 --> 00:09:23,639 Now interestingly, even though this area is black, 219 00:09:23,639 --> 00:09:26,159 because all the sub pixels have dimmed, 220 00:09:26,159 --> 00:09:28,200 they are still in fact backlit. 221 00:09:28,200 --> 00:09:30,240 Let me show you that right now. 222 00:09:30,240 --> 00:09:31,759 Now you can see as we push in here, 223 00:09:31,759 --> 00:09:32,820 you have to pardon the noise, 224 00:09:32,820 --> 00:09:38,019 an extremely high iso to get this shot through a macro lens you can see even the dimmed pixels 225 00:09:38,019 --> 00:09:42,500 part of the liquid crystal display is it's now trying to block all light from penetrating through 226 00:09:42,500 --> 00:09:48,100 but it's still a backlit pixel and that's one of the fundamental limitations of an lcd screen 227 00:09:48,100 --> 00:09:52,259 you can see this effect on an lcd screen in the credits of a film because you've got almost 228 00:09:52,259 --> 00:09:57,220 completely black image but because there's white text the entire backlight has to be on to display 229 00:09:57,220 --> 00:10:02,259 the white which means light will leak out from the black pixels which means it's not true black 230 00:10:02,820 --> 00:10:08,820 There is another technology that's becoming much more common these days, and that is an OLED screen, organic light-emitting diode. 231 00:10:09,159 --> 00:10:14,779 I did want to include a comparison between an LCD panel and an OLED panel, but I didn't actually have an OLED TV. 232 00:10:15,419 --> 00:10:25,200 And by sheer luck, right in the middle of me shooting all this footage, LG got in touch and offered to supply me with an OLED TV for the purpose of making this video, which I really appreciate. 233 00:10:25,600 --> 00:10:26,179 Thanks, LG. 234 00:10:26,559 --> 00:10:27,539 Why don't we go and take a look at it? 235 00:10:27,779 --> 00:10:31,159 This is a 77-inch LG OLED TV. 236 00:10:31,659 --> 00:10:35,679 The way OLED technology works is that each pixel is self-illuminating, 237 00:10:36,120 --> 00:10:38,279 depending on how much voltage is passing through it, 238 00:10:38,320 --> 00:10:41,000 which means there's no global backlight on the TV. 239 00:10:41,559 --> 00:10:45,379 Each pixel is individually in control of how bright it is, 240 00:10:45,500 --> 00:10:46,879 and it's not being lit from behind. 241 00:10:46,879 --> 00:10:51,799 And that means when we go to our high ISO experiment, just like we did on the LCD, 242 00:10:52,159 --> 00:10:56,980 that when there's an area of black on the screen, all of those pixels are off. 243 00:10:57,220 --> 00:11:00,720 And you can see here where I'm putting my cursor in front of the lens, 244 00:11:00,720 --> 00:11:05,039 You can see each subpixel lighting up and then completely turning off when it goes away. 245 00:11:05,039 --> 00:11:10,559 This technology means much deeper blacks and the possibility of a very thin screen. 246 00:11:11,360 --> 00:11:15,679 And there you have it, a brief explanation of how a TV works in slow-mo. 247 00:11:15,679 --> 00:11:19,279 If you found that video interesting, chances are you might find some other 248 00:11:19,279 --> 00:11:21,919 videos interesting on this channel, so make sure you boop! 249 00:11:22,720 --> 00:11:25,440 And once you've booped, feel free to check out our... 250 00:11:27,039 --> 00:11:27,759 It's just there. 251 00:11:27,759 --> 00:11:36,080 thank you very much for watching that was good timing wasn't it tv timed out and all this fireworks