1 00:00:00,080 --> 00:00:05,401 Today, we’re gonna be talking about one of the  many items behind me in this set. 2 00:00:05,401 --> 00:00:09,522 A set which, for some reason, some of you think isn’t real(?) 3 00:00:09,522 --> 00:00:11,605 Even as I reach for the item in question, 4 00:00:11,605 --> 00:00:16,062 a physical item in the physical set  that I physically sit in front of, 5 00:00:16,062 --> 00:00:21,258 a few of you will convince yourselves that this  is all an elaborate compositing effort because… 6 00:00:22,000 --> 00:00:24,042 well frankly I don’t know why. 7 00:00:24,042 --> 00:00:28,902 I mean, it should be obvious from my videos that After Effects is a program I open accidentally, 8 00:00:28,902 --> 00:00:32,777 stare at in terror,  and then feel guilty about never bothering to learn 9 00:00:32,777 --> 00:00:35,185 despite multiple new years resolutions. 10 00:00:35,185 --> 00:00:41,140 And yet some of you think me and Captain Disillusion are the same person - how? 11 00:00:41,140 --> 00:00:42,964 We sound nothing al- 12 00:00:42,964 --> 00:00:45,120 anyway I will now reach for the thing. 13 00:00:48,658 --> 00:00:51,393 That is a real dust spot, by the way. 14 00:00:51,600 --> 00:00:58,640 This is a Canon F-1, a 35mm single-lens  reflex camera introduced in 1971. 15 00:00:59,200 --> 00:01:04,189 Single-lens reflex, often shortened to SLR, means  that the view through the viewfinder 16 00:01:04,189 --> 00:01:07,309 is through the same lens that exposes the film. 17 00:01:07,309 --> 00:01:10,530 This is done with the aid of a mirror which redirects light from the lens 18 00:01:10,530 --> 00:01:17,155 onto a ground-glass focusing screen to allow the shot to be composed exactly as it will be captured on film, 19 00:01:17,155 --> 00:01:23,840 eliminating the parallax error from a separate viewfinder and allowing you to preview  the depth-of-field of a stopped-down lens. 20 00:01:23,840 --> 00:01:27,107 When the shutter is released, the mirror is  swung up and out of the way, 21 00:01:27,107 --> 00:01:30,848 allowing the light from the lens to land on the film itself 22 00:01:30,848 --> 00:01:32,864 (after the shutter has opened, of course). 23 00:01:33,360 --> 00:01:37,882 I love this camera, though I haven’t used it  in quite some time, 24 00:01:37,882 --> 00:01:42,199 and we’re gonna talk a lot about analog photography as time goes on but 25 00:01:42,199 --> 00:01:47,929 this particular video is about one fundamental aspect of how you use it - its light meter. 26 00:01:47,929 --> 00:01:55,227 Now, quick side-note, there were plenty of cameras with automatic exposure available to the consumer when this was released. 27 00:01:55,227 --> 00:02:02,400 Like this Olympus Pen EES-2, which you better believe we’ll talk about  someday because it’s got all sorts of weirdness,   28 00:02:02,400 --> 00:02:07,849 but the Canon F-1 is entirely manual, and in fact  entirely mechanical. 29 00:02:07,849 --> 00:02:08,859 That’s a large part of why I love it. 30 00:02:08,859 --> 00:02:16,634 It’s built like a tank, weighing in at just shy of 850 grams or nearly 2 pounds. 31 00:02:16,634 --> 00:02:19,594 That’s without a lens or film, mind you. 32 00:02:19,594 --> 00:02:22,360 Lightness was never a priority. 33 00:02:22,360 --> 00:02:26,723 By the way, despite its uncanny resemblance to some sort of  LCD screen, 34 00:02:26,723 --> 00:02:31,923 this thing is in fact nothing but a holder for the torn-off end of a box of film, 35 00:02:31,923 --> 00:02:34,832 to serve as a reminder of what ya put in it. 36 00:02:35,200 --> 00:02:38,340 Interacting with this camera is so delightful - 37 00:02:38,340 --> 00:02:42,945 everything is where it is because that’s where it needed to be. 38 00:02:42,945 --> 00:02:49,615 All the controls are physically  connected to the mechanisms they activitave which makes them delightfully chunky. 39 00:02:49,615 --> 00:02:55,334 You can see how turning the film advance lever cocks the shutter by moving the two halves of the shutter curtain in unison, 40 00:02:55,334 --> 00:03:01,458 and you can even hear the little clockwork mechanism that controls the shutter’s timing at long exposures. 41 00:03:01,458 --> 00:03:02,491 Take a listen. 42 00:03:02,491 --> 00:03:03,573 [ticking sound] 43 00:03:03,573 --> 00:03:04,575 [clack; ticking stops] 44 00:03:04,720 --> 00:03:10,179 Still, even with the constraints in  place, Canon managed to make this brick of a camera 45 00:03:10,179 --> 00:03:13,389 decently ergonomic (for righties, anyway). 46 00:03:13,389 --> 00:03:21,421 Your thumb, index finger, and middle fingers rest naturally on the film advance,  shutter release, and front control respectively. 47 00:03:21,760 --> 00:03:24,772 My personal favorite thing is that front  control. 48 00:03:24,772 --> 00:03:30,960 Push the lever towards the lens and it closes the aperture so you can get  a depth-of-field preview in the viewfinder, 49 00:03:30,960 --> 00:03:37,399 but turn it the other way and you can feel  that you’re winding something up. 50 00:03:37,399 --> 00:03:38,518 Well… 51 00:03:38,872 --> 00:03:42,354 [rapid high pitched ticking] 52 00:03:43,772 --> 00:03:45,772 Oh god, the suspense. 53 00:03:48,167 --> 00:03:49,139 CLACK 54 00:03:49,493 --> 00:03:52,511 I just love that. That’s its self-timer. 55 00:03:52,511 --> 00:03:54,606 Oh, and that little lever on the bottom? 56 00:03:54,606 --> 00:04:01,616 That is used to lock the aperture preview in place, and lift the  mirror for vibration-free long exposures. 57 00:04:01,616 --> 00:04:05,840 This camera requires no batteries to  function and yet it can do pretty much   58 00:04:05,840 --> 00:04:09,957 anything you can reasonably  expect a 35mm camera to do.   59 00:04:10,640 --> 00:04:13,816 Well, aside from auto-focus and motorized film  winding. 60 00:04:13,816 --> 00:04:16,080 I did say this was entirely manual. 61 00:04:16,720 --> 00:04:21,792 The F-1 was designed to be incredibly modular,  though, and you could accessorize it 62 00:04:21,792 --> 00:04:26,878 with all sorts of things from motor drives to different  viewfinders to bulk film backings. 63 00:04:26,878 --> 00:04:30,954 This one, though, is in its stock form. It has the  standard everything. 64 00:04:30,954 --> 00:04:38,000 And, while it does not need any batteries whatsoever to function, it  does have a battery compartment on the bottom.   65 00:04:38,560 --> 00:04:42,468 In here lies a small coin battery which powers  the light meter. 66 00:04:42,468 --> 00:04:43,633 What’s a light meter? 67 00:04:43,633 --> 00:04:48,000 Well, it’s not a questionable astronomical  unit, it’s instead an information display. 68 00:04:48,720 --> 00:04:51,956 Alright, quick crash-course in basic photography. 69 00:04:51,956 --> 00:04:58,971 Almost every camera ever can control the amount of light that hits the film or image sensor in two ways: 70 00:04:58,971 --> 00:05:01,520 the lens aperture, and the shutter speed. 71 00:05:02,080 --> 00:05:08,080 Inside the lens is a multi-bladed diaphragm that  can, to put it in rather basic terms, reduce the   72 00:05:08,080 --> 00:05:11,107 size of the lens’s opening through constriction. 73 00:05:11,107 --> 00:05:17,216 Those are what the F numbers on a lens are, and the higher the number, the more constricted that opening becomes, 74 00:05:17,216 --> 00:05:20,754 thus the less light makes it through to the film or sensor. 75 00:05:20,754 --> 00:05:23,791 A side-effect of this is that the depth-of-field, 76 00:05:23,791 --> 00:05:29,259 that’s the range of depths that are in-focus, becomes  deeper the more constricted the lens becomes. 77 00:05:29,520 --> 00:05:33,576 That means that more of the image is in focus,  much to the chagrin of bokeh fans, 78 00:05:33,576 --> 00:05:37,920 when a higher F number, and thus smaller aperture, is used. 79 00:05:37,920 --> 00:05:43,177 Note that for landscape photography and other scenarios where nothing is close to the camera, 80 00:05:43,177 --> 00:05:46,301 the depth-of-field becomes more or less irrelevant. 81 00:05:46,480 --> 00:05:49,747 The shutter speed, meanwhile, is (in still photography) 82 00:05:49,747 --> 00:05:52,971 the amount of time the shutter remains open. 83 00:05:52,971 --> 00:05:59,563 Leave it open for longer and you can collect more light, hardly open it at all and you collect less of it. 84 00:05:59,563 --> 00:06:05,124 The trade-off here is that long exposures require very still scenery (and probably a tripod) 85 00:06:05,124 --> 00:06:07,586 as any motion will be blurred. 86 00:06:07,586 --> 00:06:14,774 Shorter exposures on the other hand will freeze motion, but they require more light through a wider-open aperture. 87 00:06:14,774 --> 00:06:22,458 Shutter speed is measured in fractions of a second, and this camera is capable of speeds from 1 second to 1/2000th of a second. 88 00:06:22,800 --> 00:06:27,821 B, short for bulb, will leave the shutter open  as long as the shutter release is pressed. 89 00:06:28,160 --> 00:06:31,920 There’s an inverse relationship  between shutter speed and aperture.   90 00:06:31,920 --> 00:06:37,520 Higher F numbers allow less light through the lens  which means the shutter has to stay open longer   91 00:06:37,520 --> 00:06:39,870 to collect the same amount of light. 92 00:06:39,870 --> 00:06:46,938 And, if a shorter shutter speed is desired, the aperture has to open wider to allow more light through the  lens. 93 00:06:46,938 --> 00:06:53,600 In order for the exposure to be correct, the aperture and shutter speed must be an appropriate combination   94 00:06:53,600 --> 00:06:58,781 for the amount of light available in the scene and  the sensitivity of the film or sensor. 95 00:06:58,781 --> 00:07:05,365 However, once you know one combination that works, you can  adjust the shutter or aperture up or down 96 00:07:05,365 --> 00:07:09,758 so long as you adjust the other setting appropriately in  the opposite direction. 97 00:07:09,758 --> 00:07:16,247 The F-numbers, by the way, are as weird as they seem to be because the number itself is a geometric ratio, 98 00:07:16,247 --> 00:07:22,720 but we want to have stops at each value that halves or doubles  the amount of total light going through the lens   99 00:07:22,720 --> 00:07:25,637 in order to correspond to the available  shutter speeds. 100 00:07:25,637 --> 00:07:27,513 We call those stops… 101 00:07:27,513 --> 00:07:28,530 stops. 102 00:07:29,040 --> 00:07:31,610 So now we've come to the metering bit. 103 00:07:31,610 --> 00:07:36,620 Every filmstock has a certain sensitivity to light, known as its film speed. 104 00:07:36,620 --> 00:07:42,981 The term speed comes from the fact that exposure time will vary based upon sensitivity, all else being equal. 105 00:07:42,981 --> 00:07:48,417 We now call that the ISO, though back when this camera was made it was called the ASA 106 00:07:48,417 --> 00:07:53,055 (the initialism for the American Standards Association, now known as ANSI). 107 00:07:53,055 --> 00:07:58,336 See, back then, Germany was doing its own  thing with a logarithmic system they called DIN, 108 00:07:58,336 --> 00:08:06,239 the acronym for their standards organization, incidentally, but  in 1974 the International Standards Organization said 109 00:08:06,239 --> 00:08:11,580 “ya know we’re gonna just mash the ASA and the  DIN together, and now that’s the ISO” 110 00:08:11,580 --> 00:08:19,849 but nobody ever remembers the DIN half of it: the  ISO 100 should really be 100/21° 111 00:08:19,849 --> 00:08:24,439 so in a weird way we’re still using ASA but calling  it ISO. 112 00:08:24,439 --> 00:08:26,372 At least, outside of Germany. 113 00:08:26,372 --> 00:08:27,179 Anyway… 114 00:08:27,520 --> 00:08:30,022 Nope, one more tangent, I S O. 115 00:08:30,022 --> 00:08:31,870 I say the three letters. Why? 116 00:08:31,870 --> 00:08:37,680 Because ISO and "eye-so" are so close to each other that I  don’t think it makes sense to force the acronym. 117 00:08:38,480 --> 00:08:42,118 Does it matter? Of course not, it’s just,  like, my opinion 118 00:08:42,118 --> 00:08:48,226 but I will at least grant that it’s less atrocious than calling this  “Nitsah” which they’re trying real hard 119 00:08:48,226 --> 00:08:50,684 to make a thing in case you hadn’t noticed. 120 00:08:50,684 --> 00:08:54,194 And I regret to inform you that… it’s working. 121 00:08:55,040 --> 00:09:01,943 Anyway, modern digital cameras have an ISO  setting because you can change the sensitivity of the image sensor, 122 00:09:01,943 --> 00:09:07,215 but back when we were using good ‘ol emulsions of silver halides on a clear plastic backing, 123 00:09:07,215 --> 00:09:11,367 you’d be stuck with whatever  the sensitivity was of the film you bought. 124 00:09:11,680 --> 00:09:15,280 Of course there are many kinds  of films from many manufacturers,   125 00:09:15,280 --> 00:09:18,335 and the film speed is itself something  of a trade-off - 126 00:09:18,335 --> 00:09:24,165 more sensitive films are usually grainier, so you’d want to pick  the appropriate film for your situation. 127 00:09:24,720 --> 00:09:30,960 But now… well how are you supposed to know  what shutter speed and aperture setting you should use?   128 00:09:30,960 --> 00:09:36,240 You have to get the exposure correct if you want  the resulting image to have decent dynamic range.   129 00:09:36,240 --> 00:09:42,319 Otherwise it will be blown out from overexposure,  or a dark mess without any detail. 130 00:09:42,319 --> 00:09:46,750 Well, there are some general rules of thumb you can use  in certain situations. 131 00:09:46,750 --> 00:09:51,058 For example, on a clear sunny day you can use the Sunny 16 rule: 132 00:09:51,058 --> 00:09:56,838 set the aperture to 16, and the shutter speed to the value that most closely matches the film speed. 133 00:09:56,838 --> 00:10:02,819 So, if your ISO is 100 - one one hundredth of a second, or the closest available setting 134 00:10:02,819 --> 00:10:04,859 (on this camera, it would be 125). 135 00:10:05,360 --> 00:10:10,189 This works because a doubling in film speed  equals one stop in exposure - 136 00:10:10,189 --> 00:10:17,815 it requires half as much light, and at F16 the correct  shutter speeds happens to match the film speed numerically. 137 00:10:17,815 --> 00:10:22,365 If you need a faster shutter speed for a given shot, just open up the aperture 138 00:10:22,365 --> 00:10:25,280 an equal number of stops that you  increased the shutter speed to compensate. 139 00:10:26,080 --> 00:10:26,770 But, 140 00:10:27,015 --> 00:10:31,853 news flash, not every photograph is  taken outdoors on a sunny day. 141 00:10:31,853 --> 00:10:36,725 Wouldn’t it be nice to have something that can tell [clunk] you the correct exposure for any given scenario? 142 00:10:37,040 --> 00:10:38,980 Enter the light meter. 143 00:10:38,980 --> 00:10:46,004 These devices are able to, with the aid of some sort of light sensor, provide the user with an appropriate exposure value. 144 00:10:46,004 --> 00:10:49,670 These devices were originally hand-held, and were fairly crude. 145 00:10:49,670 --> 00:10:55,920 Generally they’d just have a needle-type readout which would point to the appropriate aperture value for a given film and shutter speed.   146 00:10:55,920 --> 00:11:00,480 To use them, you’d bring them to your subject  and point them at something which was close to  a 147 00:11:00,480 --> 00:11:04,560 middle-grey in terms of brightness, then  you’d set your camera up appropriately. 148 00:11:05,280 --> 00:11:10,080 You can still buy handheld light meters today,  though they’ve been digitified of course.   149 00:11:10,080 --> 00:11:13,600 But before long they were integrated  into camera bodies themselves.   150 00:11:13,600 --> 00:11:18,913 And that’s why this otherwise mechanical camera  has a battery compartment. 151 00:11:18,913 --> 00:11:25,855 Now, keep in mind this camera was originally released in 1971 (though this example is a later revision). 152 00:11:25,855 --> 00:11:31,979 Its light meter will be limited to the same sort of analog tech  that was found in the handheld meters of the time.   153 00:11:32,240 --> 00:11:37,875 But, and this is why I wanted to make this video,  it was done in an extremely clever way that 154 00:11:37,875 --> 00:11:43,360 not only simplified its operation to the user, but  allowed for more flexible use of the camera. 155 00:11:43,920 --> 00:11:48,432 The meter appears as a small display to the right  of the image in the viewfinder. 156 00:11:48,432 --> 00:11:53,683 Right now the camera doesn’t have a lens on it, but watch what  happens when I put one on. 157 00:11:53,683 --> 00:11:55,969 [clicky sounds of lens being attached] 158 00:11:55,969 --> 00:11:58,582 The small circle moved upwards. 159 00:11:58,582 --> 00:12:02,334 That circle is mechanically linked to  this little piece here. 160 00:12:02,334 --> 00:12:06,224 You can see that as I move it with my finger, the ring moves up and down. 161 00:12:06,224 --> 00:12:09,517 This engages with a small peg on the lens itself. 162 00:12:09,517 --> 00:12:14,800 Once installed on the camera, moving the aperture  ring on the lens causes that ring to move. 163 00:12:15,520 --> 00:12:19,294 Now, in addition to the ring, there’s a small  horizontal line. 164 00:12:19,294 --> 00:12:22,097 Right now it’s sitting in the bottom red area. 165 00:12:22,097 --> 00:12:27,041 This is actually a needle that will move depending on how much light the camera sees. 166 00:12:27,041 --> 00:12:29,731 And this is where the battery comes into play. 167 00:12:29,731 --> 00:12:34,107 You may have noticed this power switch - all that does is turn on the light meter. 168 00:12:34,107 --> 00:12:38,494 That little blue mark in the meter’s display is used as a battery level check. 169 00:12:38,494 --> 00:12:44,193 You can see there’s a little sticker here reminding you that to check the battery level, the shutter speed should be set to 2000 170 00:12:44,193 --> 00:12:45,680 and the ASA to 100. 171 00:12:46,240 --> 00:12:50,490 Then when you move the switch to the  check position, the needle should jump up to the blue mark 172 00:12:50,490 --> 00:12:53,396 and so long as it does - the battery’s OK! 173 00:12:53,600 --> 00:12:58,468 If it doesn’t make it to the blue mark, well it’s  flat and if it overshoots it… 174 00:12:58,468 --> 00:12:59,659 we’ll get to that. 175 00:12:59,920 --> 00:13:05,085 When the meter is turned on you can see  the needle move with the amount of light that hits the camera. 176 00:13:05,085 --> 00:13:07,661 The brighter the image the higher it goes! 177 00:13:07,661 --> 00:13:08,800 But… 178 00:13:08,800 --> 00:13:11,155 where exactly is it measuring? 179 00:13:11,155 --> 00:13:15,168 You probably noticed the darker portion of the viewfinder towards the center. 180 00:13:15,168 --> 00:13:18,054 That is the sensitive area of the light meter. 181 00:13:18,054 --> 00:13:23,829 With a lens on, you can see that it’s only what’s in this area  that affects the needle’s behavior. 182 00:13:23,829 --> 00:13:26,821 But… how is that possible? 183 00:13:26,821 --> 00:13:29,020 Where is the actual sensor? 184 00:13:29,020 --> 00:13:32,807 Surely we didn’t have transparent light sensors in 1971. 185 00:13:33,360 --> 00:13:35,986 Well maybe we did but that’s not what’s going  on here. 186 00:13:35,986 --> 00:13:38,634 Again, it’s extremely clever. 187 00:13:38,634 --> 00:13:42,840 One of the many things you could customize on this camera  is the focusing screen. 188 00:13:42,840 --> 00:13:48,863 To remove it, you simply remove the viewfinder by pressing in these little lock buttons and sliding it towards the rear. 189 00:13:49,088 --> 00:13:52,648 And… there’s the focusing screen. 190 00:13:52,648 --> 00:13:58,641 Kinda trippy, huh? That’s what we were looking at in the viewfinder, but now we’re looking… 191 00:13:58,641 --> 00:13:59,775 down at it. 192 00:13:59,775 --> 00:14:02,965 In fact all the viewfinder is is a prism, 193 00:14:03,280 --> 00:14:08,895 a roof pentaprism to be precise, there to redirect  your view from the eyepiece downard 194 00:14:08,895 --> 00:14:10,818 and flip the image horizontally. 195 00:14:10,818 --> 00:14:15,566 This creates the distinctive hump you see above the lens of all SLRs to this day, 196 00:14:15,566 --> 00:14:21,349 though I must say I much prefer these  sharp lines which don’t hide the nature of the thing 197 00:14:21,349 --> 00:14:23,941 to the blobular designs of today. 198 00:14:23,941 --> 00:14:27,886 Anyway, this is the focusing screen and it, too,  is removable. 199 00:14:27,886 --> 00:14:33,225 Before I even remove it, though, something about it seems weird. 200 00:14:33,225 --> 00:14:36,727 That darker region appears to be… floating. 201 00:14:37,200 --> 00:14:43,192 Now, this is obvious in person thanks to  stereoscopic vision, but it might not come across well on camera. 202 00:14:43,192 --> 00:14:44,641 I’ll try my best, though. 203 00:14:44,641 --> 00:14:50,918 At the very least, you can see that the circular focusing aids in the center are actually separate from that darker region. 204 00:14:50,918 --> 00:14:55,081 If I pop the focusing screen out, you’ll get a clue as to why. 205 00:14:55,081 --> 00:14:58,179 See that little window there? Look through it. 206 00:14:58,179 --> 00:15:00,000 Weeeeird. 207 00:15:00,640 --> 00:15:08,368 That dark region is actually a semi-transparent  mirror that is floating in the middle of the glass somehow. 208 00:15:08,368 --> 00:15:11,466 I really want to see how these were manufactured. 209 00:15:11,466 --> 00:15:17,197 But anyway, it redirects some of the light coming up through the focusing screen out  this little window 210 00:15:17,197 --> 00:15:20,967 and if we look from the front you’ll see what lies behind it. 211 00:15:20,967 --> 00:15:22,409 The light sensor. 212 00:15:22,409 --> 00:15:30,755 From the looks of it it seems to be a simple light-dependent resistor or LDR, though it’s obviously a little fancier than the one in your garden variety night light. 213 00:15:30,755 --> 00:15:36,091 The amount of light that falls on this will, thanks to the battery and the simple electronics it powers, 214 00:15:36,091 --> 00:15:39,261 determine where the needle in the meter lands. 215 00:15:39,600 --> 00:15:46,400 So, in the end, that rectangle is simply the  dark region left by a semi-transparent mirror   216 00:15:46,400 --> 00:15:54,770 embedded in the glass of the focusing screen at  a 45 degree angle so it can redirect a portion of light onto the sensor. 217 00:15:54,770 --> 00:15:57,400 That’s what I call  neat. 218 00:15:57,400 --> 00:16:03,252 Now that we know where the meter measures, how it works, and what it does… how does one use it? 219 00:16:03,252 --> 00:16:05,478 You may very well have figured it out by now. 220 00:16:05,478 --> 00:16:10,208 This variety of meter is called a match-needle  meter, and that ring? 221 00:16:10,208 --> 00:16:12,116 Well, it’s your target. 222 00:16:12,240 --> 00:16:16,240 To use this camera’s light meter, you  first point the camera so that something   223 00:16:16,240 --> 00:16:20,080 in the scene that’s not too bright or too  dark is within that metering region.   224 00:16:20,640 --> 00:16:26,080 Light meters in cameras are generally calibrated  to a middle-grey value, and this is no exception.   225 00:16:26,720 --> 00:16:31,120 Now, simply turn the aperture ring on the  lens until the ring surrounds the needle.   226 00:16:31,680 --> 00:16:34,255 You are now set to the correct exposure  setting 227 00:16:34,255 --> 00:16:39,191 so you can recompose your shot however you like, hit the shutter release, and you're done! 228 00:16:39,191 --> 00:16:43,205 One exposure down, 23, maybe 35 more to go! 229 00:16:43,680 --> 00:16:46,401 But what if that combination isn’t what I want? 230 00:16:46,401 --> 00:16:52,462 Maybe I have to stop the lens way way down in order to match the needle's position expose correctly. 231 00:16:52,707 --> 00:16:55,980 I’ll lose my sweet  sweet bokeh! 232 00:16:55,980 --> 00:17:00,965 Well, nothing a little after-the-fact AI-powered image processing can’t fix… I mean... 233 00:17:00,965 --> 00:17:02,398 that’s no problem at all! 234 00:17:02,398 --> 00:17:05,606 Simply adjust the shutter speed so that it’s faster. 235 00:17:05,606 --> 00:17:08,049 Aha! The needle moved. 236 00:17:08,049 --> 00:17:11,098 Here’s where the other  part of this genius system comes in. 237 00:17:11,440 --> 00:17:17,200 The actual sensitivity of the light meter itself is  affected by both the selected shutter speed   238 00:17:17,200 --> 00:17:19,184 and also the film speed. 239 00:17:19,184 --> 00:17:22,288 Perhaps you noticed this little insert in the shutter speed dial. 240 00:17:22,288 --> 00:17:29,448 Rotate the dial while pulling up on it and you can change  the film speed setting which will make the meter more or less sensitive. 241 00:17:29,448 --> 00:17:32,701 And the shutter speed alone has the same effect. 242 00:17:32,701 --> 00:17:39,635 Increasing shutter speed causes the needle to fall down, which means you need to open the lens up to match. 243 00:17:39,635 --> 00:17:44,344 Now, you could have worked this out in your head by just  counting the stops to, say, F2 244 00:17:44,344 --> 00:17:47,711 and then increasing the shutter speed by the same number of stops. 245 00:17:47,711 --> 00:17:52,882 But having the meter work differently depending on the shutter speed offers a sort of sanity check. 246 00:17:52,882 --> 00:17:57,637 It also demonstrates the relationship between shutter speed and aperture beautifully. 247 00:17:57,637 --> 00:18:03,125 Each stop you move in shutter speed requires two clicks of the aperture ring to compensate. 248 00:18:03,125 --> 00:18:06,698 Two clicks because this lens has detents at half stops. 249 00:18:07,280 --> 00:18:14,202 Most elegantly, though? The matching nature  allows for shutter priority or aperture priority exposure. 250 00:18:14,202 --> 00:18:18,358 Rather than just point the camera at the scene and find a combo that works, 251 00:18:18,358 --> 00:18:22,800 you can fix one of those variables ahead of  time and adjust the other as needed. 252 00:18:23,360 --> 00:18:28,261 Say you want a stopped-down aperture  of F16 for a deep depth of field. 253 00:18:28,261 --> 00:18:34,541 Well, set the lens to F16 and keep changing the shutter  speed until the needle gets in that ring.   254 00:18:34,800 --> 00:18:39,641 Or, perhaps you need a fast shutter speed to  freeze motion in action shots. 255 00:18:39,641 --> 00:18:45,644 Simply set the shutter speed to 1000, and move the aperture  ring until the ring surrounds the needle. 256 00:18:45,644 --> 00:18:46,443 Easy! 257 00:18:46,880 --> 00:18:54,607 This metering arrangement is not only intuitive,  but it’s flexible and also just a great teaching aid to those learning photography. 258 00:18:54,607 --> 00:19:00,640 You see hints of it in modern interfaces, and then of course there’s even more powerful stuff these days like histograms and whatnot,   259 00:19:00,640 --> 00:19:06,962 but there’s just something about the way  this works that is… beautifully elegant to me. 260 00:19:06,962 --> 00:19:08,871 Should we talk about the weirdness, though? 261 00:19:08,871 --> 00:19:10,240 Let’s talk about the weirdness. 262 00:19:10,960 --> 00:19:13,715 First, there’s a limit to its range of operation. 263 00:19:13,715 --> 00:19:17,253 Watch what happens as I approach a shutter speed of one second. 264 00:19:17,253 --> 00:19:20,587 At a quarter of a second, the meter turns red. 265 00:19:20,587 --> 00:19:24,657 It doesn’t exactly stop working, but it behaves erratically. 266 00:19:24,657 --> 00:19:30,356 If I increase the film speed to 1600, the meter goes red at a thirtieth of a second. 267 00:19:30,356 --> 00:19:33,360 And here, at really slow shutter speeds, the needle just… 268 00:19:34,000 --> 00:19:36,767 stops changing at all even when it should. 269 00:19:36,767 --> 00:19:39,040 Now the meter is definitely not working right. 270 00:19:39,600 --> 00:19:43,365 What’s going on here is that the  meter is a lot simpler than you may imagine.   271 00:19:43,680 --> 00:19:47,760 Changing the shutter speed setting simply  changes how sensitive the meter becomes.   272 00:19:47,760 --> 00:19:53,007 As you slow the shutter, you need to close the  aperture down in equivalent stops for the same exposure. 273 00:19:53,007 --> 00:20:00,378 The meter needs to move the needle higher to indicate that, which means the needle becomes more sensitive to given amounts of light. 274 00:20:00,800 --> 00:20:04,800 But the same thing needs to happen  when you increase the film speed.   275 00:20:04,800 --> 00:20:09,200 If you doubled the film speed, you'd need  half as much light for the same exposure,   276 00:20:09,200 --> 00:20:12,077 so the needle needs to move one stop higher. 277 00:20:12,077 --> 00:20:18,400 Doubling the film speed demands that the sensitivity of the meter change exactly as if the shutter speed were cut in half.   278 00:20:19,120 --> 00:20:23,577 And the simplest way to do this? Just shift everything over. 279 00:20:23,577 --> 00:20:29,774 The needle will indicate the same apertures for a doubled film speed as it would for a halved shutter speed, 280 00:20:29,774 --> 00:20:36,080 so if you can shift those sensitivities around, you  can adjust the meter for different film speeds. 281 00:20:36,640 --> 00:20:40,000 That’s exactly what changing  the film speed setting does,   282 00:20:40,000 --> 00:20:44,160 in fact that’s literally what it does because  we’re dealing with a mechanical contraption.   283 00:20:44,800 --> 00:20:50,160 Adjusting the film speed essentially relocates  the different sensitivities of the light meter   284 00:20:50,160 --> 00:20:53,571 independently of the camera’s shutter mechanism. 285 00:20:53,571 --> 00:20:59,923 There are more meter sensitivities than there are shutter speeds on the high end, but there aren’t on the low end. 286 00:20:59,923 --> 00:21:05,485 The meter just isn’t sensitive enough to tell you how to expose  a low-light shot. 287 00:21:05,485 --> 00:21:15,560 So, as the film speed increases, the lowest speed settings become locked out because that sensitivity is now assigned to a higher shutter speed. 288 00:21:15,560 --> 00:21:20,087 Each doubling of film  speed locks out the next lowest shutter speed. 289 00:21:20,400 --> 00:21:26,929 In the end, the meter is just an analog device  that’s been finely calibrated to move the needle logarithmically. 290 00:21:26,929 --> 00:21:31,765 Each doubling of light landing on the sensor makes it move the same distance upward. 291 00:21:31,765 --> 00:21:35,768 I imagine each sensitivity level is just  adding a different resistor to the mix. 292 00:21:36,000 --> 00:21:40,249 Which brings us to the next bit of weirdness: batteries. 293 00:21:40,249 --> 00:21:46,640 When this camera was made, we were still manufacturing mercury batteries because, ya know, we hadn’t yet come to grips with the fact   294 00:21:46,640 --> 00:21:51,680 that the garbage can isn’t a magic receptacle  that makes things harmlessly disappear forever. 295 00:21:51,680 --> 00:21:56,468 The trouble is, mercury batteries produced 1.35  volts. 296 00:21:56,468 --> 00:21:58,874 That’s a weird voltage these days. 297 00:21:58,874 --> 00:22:03,647 While you can buy a replacement battery that fits  perfectly in the battery compartment, 298 00:22:03,647 --> 00:22:07,714 it will likely be a 1.5 volt alkaline battery. 299 00:22:07,714 --> 00:22:14,552 You might not think that’s enough to matter but remember this is an all-analog system which is calibrated to behave logarithmically. 300 00:22:14,552 --> 00:22:18,742 The voltage matters a lot, and those batteries simply do not work. 301 00:22:18,742 --> 00:22:23,331 They push the needle way too high and it will never give you an accurate reading. 302 00:22:23,331 --> 00:22:28,659 If you do a battery check with one of these alkaline batteries, the needle will end up all the way up here. 303 00:22:28,659 --> 00:22:30,206 Trust me, I know. 304 00:22:30,206 --> 00:22:34,160 That same sort of error makes its way into every metering scenario. 305 00:22:34,800 --> 00:22:37,185 However, there is a solution! 306 00:22:37,185 --> 00:22:43,157 Zinc-air batteries, which produce electricity through reacting with oxygen in the air, are commonly available. 307 00:22:43,157 --> 00:22:49,040 They’re pretty neat all on their own, featuring a surprisingly large energy  density due to the nature of the reaction,   308 00:22:49,040 --> 00:22:53,120 but they have a time-limited life  because you can’t stop the reaction   309 00:22:53,120 --> 00:22:55,548 once you remove the adhesive pull tab. 310 00:22:55,548 --> 00:23:01,710 However, for some applications like hearing aids, this drawback is more than made up for by their energy density. 311 00:23:01,710 --> 00:23:09,649 And most importantly, the voltage they produce is close enough to 1.35 that they can be used in cameras like these. 312 00:23:09,840 --> 00:23:14,316 Now, you can buy a zinc-air drop-in replacement online for  about $5 313 00:23:14,316 --> 00:23:19,959 but you’ll be quickly annoyed with that option since, as I said, they have a built-in time  limit. 314 00:23:19,959 --> 00:23:24,866 So, pro tip, get yourself some 675 hearing aid batteries. 315 00:23:24,866 --> 00:23:31,844 They’re about the same thickness as the PX625 battery this camera is designed to take, and although they’re not the right diameter, 316 00:23:31,844 --> 00:23:35,687 a simple loop of wire insulation will center it well enough. 317 00:23:35,687 --> 00:23:38,675 You may need to bend the camera’s negative tab up slightly, 318 00:23:38,675 --> 00:23:44,330 but this simple modification allows you to use batteries you can buy at Walmart for about a buck apiece. 319 00:23:44,330 --> 00:23:49,617 And as a happy accident, the battery compartment cover  has a couple of holes allowing air in, 320 00:23:49,617 --> 00:23:55,280 but they're small enough that in my experience a battery  will last a good couple months before it’s dead. 321 00:23:55,840 --> 00:23:59,585 You might also have asked, where is  the meter’s display? 322 00:23:59,585 --> 00:24:01,579 And how is it lit? 323 00:24:01,579 --> 00:24:05,002 You can see it in the viewfinder quite clearly, but when you remove the viewfinder 324 00:24:05,002 --> 00:24:08,284 you find just a blank hole where it was. 325 00:24:08,284 --> 00:24:11,617 Well, the meter is actually right here. 326 00:24:11,617 --> 00:24:13,582 It’s tiny! 327 00:24:13,582 --> 00:24:16,880 And this piece of translucent plastic up here is what illuminates it. 328 00:24:17,440 --> 00:24:21,301 Old cameras are filled with all these clever,  intricate mechanisms. 329 00:24:21,301 --> 00:24:27,141 I mean, think about the linkage connecting the shutter speed dial to the tiny little indicator in the meter. 330 00:24:27,141 --> 00:24:28,897 Hmm, it’s amazing. 331 00:24:28,897 --> 00:24:34,469 Oh, and you could purchase a different viewfinder which had its own battery and light source for the meter, but 332 00:24:34,469 --> 00:24:38,611 this was never really super useful since the meter doesn’t work in low light anyway. 333 00:24:38,611 --> 00:24:41,792 For outdoor photography that little window works surprisingly well. 334 00:24:42,240 --> 00:24:47,207 Speaking of, did you notice the “OFF”  position on the meter is also marked “FLASH?”   335 00:24:47,760 --> 00:24:49,248 How does that work? 336 00:24:49,248 --> 00:24:51,259 Well, it doesn’t. 337 00:24:51,259 --> 00:24:58,944 Remember there’s no automatic anything, and when this camera was made you’d use a chart on your flash itself to set exposure correctly 338 00:24:58,944 --> 00:25:01,991 based on film speed and distance to the subject. 339 00:25:01,991 --> 00:25:06,055 Oh, and that’s why the shutter speed 60 is marked in orange. 340 00:25:06,055 --> 00:25:13,260 That’s the flash synchronization speed of this camera, or the fastest shutter speed where the entire shutter is open at once 341 00:25:13,260 --> 00:25:15,881 and thus suitable for use with a flash. 342 00:25:15,881 --> 00:25:23,163 Since this camera’s shutter curtain moves horizontally, its shutter is pretty slow and you can see even with a smartphone’s slow-mo 343 00:25:23,163 --> 00:25:27,469 that any speed above 60 doesn’t expose the film all at once. 344 00:25:27,469 --> 00:25:30,756 This can actually create distortion in certain scenarios, 345 00:25:30,960 --> 00:25:34,868 so in a funny way, this old camera  has a rolling shutter. 346 00:25:34,868 --> 00:25:35,818 Go figure. 347 00:25:36,240 --> 00:25:41,600 The shutter mechanism alone is just  incredibly intricate and also fascinating,   348 00:25:41,600 --> 00:25:46,581 I mean the curtains themselves are made of  titanium. And they’re flexible! 349 00:25:46,581 --> 00:25:53,246 They roll up into these little compartments here, and move as  one unit when you cock the shutter and advance the film. 350 00:25:53,246 --> 00:25:55,525 You can see the seam right here. 351 00:25:55,525 --> 00:26:02,519 But with the press of just one button, they move apart and come back together with precise control in a fraction a second 352 00:26:02,519 --> 00:26:03,258 [CLICK] 353 00:26:03,258 --> 00:26:05,822 all done entirely mechanically. 354 00:26:05,822 --> 00:26:06,778 Amazing! 355 00:26:07,280 --> 00:26:09,600 This little thing here is  the old-style flash hookup,   356 00:26:09,600 --> 00:26:13,120 though up here by the film rewinder  you’ll find an older style of hot shoe.   357 00:26:13,840 --> 00:26:16,593 These little contacts here (along with those  inside the plug) 358 00:26:16,593 --> 00:26:21,392 are bridged right when the shutter is entirely open, signaling an electronic flash to… 359 00:26:21,392 --> 00:26:22,295 [CLICK] 360 00:26:22,295 --> 00:26:26,864 flash. But anyway, now we’re getting well into the nitty-gritty which we’ll save for later. 361 00:26:26,864 --> 00:26:31,676 I hope you enjoyed this look into the old-fashioned light metering systems of yesteryear. 362 00:26:31,676 --> 00:26:39,001 While it’s fundamentally very simple, a lot of ingenuity was built-in to make it usable, intuitive, and flexible. 363 00:26:39,001 --> 00:26:43,295 But we’ve just scratched the surface  on how this camera takes pictures. 364 00:26:43,295 --> 00:26:46,700 What about the film itself? How does that store  an image? 365 00:26:46,700 --> 00:26:51,970 And what about film development? How do film negatives become printed photographs? 366 00:26:51,970 --> 00:26:59,380 Oh, don’t worry. There’s a lot more to explore with analog photography, and before long we’ll get there. 367 00:26:59,380 --> 00:27:00,978 See you in the darkroom! 368 00:27:01,957 --> 00:27:03,976 ♫ logarithmically smooth jazz ♫ 369 00:27:04,384 --> 00:27:08,411 Single lens reflux(?), also sort… ahh already sca-rooooo-ewd it up 370 00:27:08,411 --> 00:27:11,414 and it’s great because I have to re-take the OTHER line, too! 371 00:27:11,414 --> 00:27:13,434 I don’ like how I said FUNdamental 372 00:27:13,434 --> 00:27:16,441 I forgot I need to.. Open that 373 00:27:16,441 --> 00:27:20,967 The more constricted that opening becomes. Thus, the let light… less light… 374 00:27:20,967 --> 00:27:26,322 That means that more of the image is in focus at once, much to the chagrin of bokeh fans. (the sentence shouldn’t have ended) 375 00:27:26,322 --> 00:27:29,089 When a higher F number… ugh dang yeah forgot. 376 00:27:29,361 --> 00:27:31,288 Forgot the delivery! 377 00:27:31,451 --> 00:27:32,293 [clears throat] 378 00:27:32,293 --> 00:27:32,844 So… 379 00:27:34,668 --> 00:27:36,663 So… ble ble bah buh… we’ll move it over there. 380 00:27:36,663 --> 00:27:37,277 How ‘bout that? 381 00:27:37,604 --> 00:27:38,840 But nobody eberdy… 382 00:27:39,600 --> 00:27:42,695 nobody ebedy bedu… it’s going so well.... 383 00:27:42,695 --> 00:27:47,307 But, in 1974, the International Standards Association said… 384 00:27:47,307 --> 00:27:50,148 Organization! Dang it… 385 00:27:51,591 --> 00:27:58,741 I'm aware that the ISO dictates from their righteous throne of meticulousness that it is "supposed to be" pronounced "eye-so" 386 00:27:58,741 --> 00:28:05,696 Just remember that the inventor of the GIF tried to steer the ship and look how that's working out for him. 387 00:28:05,696 --> 00:28:12,563 Anyway language is dumb.