WEBVTT Kind: captions Language: en 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. 00:00:05.401 --> 00:00:09.522 A set which, for some reason, some of you think isn’t real(?) 00:00:09.522 --> 00:00:11.605 Even as I reach for the item in question, 00:00:11.605 --> 00:00:16.062 a physical item in the physical set  that I physically sit in front of, 00:00:16.062 --> 00:00:21.258 a few of you will convince yourselves that this  is all an elaborate compositing effort because… 00:00:22.000 --> 00:00:24.042 well frankly I don’t know why. 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, 00:00:28.902 --> 00:00:32.777 stare at in terror,  and then feel guilty about never bothering to learn 00:00:32.777 --> 00:00:35.185 despite multiple new years resolutions. 00:00:35.185 --> 00:00:41.140 And yet some of you think me and Captain Disillusion are the same person - how? 00:00:41.140 --> 00:00:42.964 We sound nothing al- 00:00:42.964 --> 00:00:45.120 anyway I will now reach for the thing. 00:00:48.658 --> 00:00:51.393 That is a real dust spot, by the way. 00:00:51.600 --> 00:00:58.640 This is a Canon F-1, a 35mm single-lens  reflex camera introduced in 1971. 00:00:59.200 --> 00:01:04.189 Single-lens reflex, often shortened to SLR, means  that the view through the viewfinder 00:01:04.189 --> 00:01:07.309 is through the same lens that exposes the film. 00:01:07.309 --> 00:01:10.530 This is done with the aid of a mirror which redirects light from the lens 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, 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. 00:01:23.840 --> 00:01:27.107 When the shutter is released, the mirror is  swung up and out of the way, 00:01:27.107 --> 00:01:30.848 allowing the light from the lens to land on the film itself 00:01:30.848 --> 00:01:32.864 (after the shutter has opened, of course). 00:01:33.360 --> 00:01:37.882 I love this camera, though I haven’t used it  in quite some time, 00:01:37.882 --> 00:01:42.199 and we’re gonna talk a lot about analog photography as time goes on but 00:01:42.199 --> 00:01:47.929 this particular video is about one fundamental aspect of how you use it - its light meter. 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. 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,   00:02:02.400 --> 00:02:07.849 but the Canon F-1 is entirely manual, and in fact  entirely mechanical. 00:02:07.849 --> 00:02:08.859 That’s a large part of why I love it. 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. 00:02:16.634 --> 00:02:19.594 That’s without a lens or film, mind you. 00:02:19.594 --> 00:02:22.360 Lightness was never a priority. 00:02:22.360 --> 00:02:26.723 By the way, despite its uncanny resemblance to some sort of  LCD screen, 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, 00:02:31.923 --> 00:02:34.832 to serve as a reminder of what ya put in it. 00:02:35.200 --> 00:02:38.340 Interacting with this camera is so delightful - 00:02:38.340 --> 00:02:42.945 everything is where it is because that’s where it needed to be. 00:02:42.945 --> 00:02:49.615 All the controls are physically  connected to the mechanisms they activitave which makes them delightfully chunky. 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, 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. 00:03:01.458 --> 00:03:02.491 Take a listen. 00:03:02.491 --> 00:03:03.573 [ticking sound] 00:03:03.573 --> 00:03:04.575 [clack; ticking stops] 00:03:04.720 --> 00:03:10.179 Still, even with the constraints in  place, Canon managed to make this brick of a camera 00:03:10.179 --> 00:03:13.389 decently ergonomic (for righties, anyway). 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. 00:03:21.760 --> 00:03:24.772 My personal favorite thing is that front  control. 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, 00:03:30.960 --> 00:03:37.399 but turn it the other way and you can feel  that you’re winding something up. 00:03:37.399 --> 00:03:38.518 Well… 00:03:38.872 --> 00:03:42.354 [rapid high pitched ticking] 00:03:43.772 --> 00:03:45.772 Oh god, the suspense. 00:03:48.167 --> 00:03:49.139 CLACK 00:03:49.493 --> 00:03:52.511 I just love that. That’s its self-timer. 00:03:52.511 --> 00:03:54.606 Oh, and that little lever on the bottom? 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. 00:04:01.616 --> 00:04:05.840 This camera requires no batteries to  function and yet it can do pretty much   00:04:05.840 --> 00:04:09.957 anything you can reasonably  expect a 35mm camera to do.   00:04:10.640 --> 00:04:13.816 Well, aside from auto-focus and motorized film  winding. 00:04:13.816 --> 00:04:16.080 I did say this was entirely manual. 00:04:16.720 --> 00:04:21.792 The F-1 was designed to be incredibly modular,  though, and you could accessorize it 00:04:21.792 --> 00:04:26.878 with all sorts of things from motor drives to different  viewfinders to bulk film backings. 00:04:26.878 --> 00:04:30.954 This one, though, is in its stock form. It has the  standard everything. 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.   00:04:38.560 --> 00:04:42.468 In here lies a small coin battery which powers  the light meter. 00:04:42.468 --> 00:04:43.633 What’s a light meter? 00:04:43.633 --> 00:04:48.000 Well, it’s not a questionable astronomical  unit, it’s instead an information display. 00:04:48.720 --> 00:04:51.956 Alright, quick crash-course in basic photography. 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: 00:04:58.971 --> 00:05:01.520 the lens aperture, and the shutter speed. 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   00:05:08.080 --> 00:05:11.107 size of the lens’s opening through constriction. 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, 00:05:17.216 --> 00:05:20.754 thus the less light makes it through to the film or sensor. 00:05:20.754 --> 00:05:23.791 A side-effect of this is that the depth-of-field, 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. 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, 00:05:33.576 --> 00:05:37.920 when a higher F number, and thus smaller aperture, is used. 00:05:37.920 --> 00:05:43.177 Note that for landscape photography and other scenarios where nothing is close to the camera, 00:05:43.177 --> 00:05:46.301 the depth-of-field becomes more or less irrelevant. 00:05:46.480 --> 00:05:49.747 The shutter speed, meanwhile, is (in still photography) 00:05:49.747 --> 00:05:52.971 the amount of time the shutter remains open. 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. 00:05:59.563 --> 00:06:05.124 The trade-off here is that long exposures require very still scenery (and probably a tripod) 00:06:05.124 --> 00:06:07.586 as any motion will be blurred. 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. 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. 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. 00:06:28.160 --> 00:06:31.920 There’s an inverse relationship  between shutter speed and aperture.   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   00:06:37.520 --> 00:06:39.870 to collect the same amount of light. 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. 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   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. 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 00:07:05.365 --> 00:07:09.758 so long as you adjust the other setting appropriately in  the opposite direction. 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, 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   00:07:22.720 --> 00:07:25.637 in order to correspond to the available  shutter speeds. 00:07:25.637 --> 00:07:27.513 We call those stops… 00:07:27.513 --> 00:07:28.530 stops. 00:07:29.040 --> 00:07:31.610 So now we've come to the metering bit. 00:07:31.610 --> 00:07:36.620 Every filmstock has a certain sensitivity to light, known as its film speed. 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. 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 00:07:48.417 --> 00:07:53.055 (the initialism for the American Standards Association, now known as ANSI). 00:07:53.055 --> 00:07:58.336 See, back then, Germany was doing its own  thing with a logarithmic system they called DIN, 00:07:58.336 --> 00:08:06.239 the acronym for their standards organization, incidentally, but  in 1974 the International Standards Organization said 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” 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° 00:08:19.849 --> 00:08:24.439 so in a weird way we’re still using ASA but calling  it ISO. 00:08:24.439 --> 00:08:26.372 At least, outside of Germany. 00:08:26.372 --> 00:08:27.179 Anyway… 00:08:27.520 --> 00:08:30.022 Nope, one more tangent, I S O. 00:08:30.022 --> 00:08:31.870 I say the three letters. Why? 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. 00:08:38.480 --> 00:08:42.118 Does it matter? Of course not, it’s just,  like, my opinion 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 00:08:48.226 --> 00:08:50.684 to make a thing in case you hadn’t noticed. 00:08:50.684 --> 00:08:54.194 And I regret to inform you that… it’s working. 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, 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, 00:09:07.215 --> 00:09:11.367 you’d be stuck with whatever  the sensitivity was of the film you bought. 00:09:11.680 --> 00:09:15.280 Of course there are many kinds  of films from many manufacturers,   00:09:15.280 --> 00:09:18.335 and the film speed is itself something  of a trade-off - 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. 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?   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.   00:09:36.240 --> 00:09:42.319 Otherwise it will be blown out from overexposure,  or a dark mess without any detail. 00:09:42.319 --> 00:09:46.750 Well, there are some general rules of thumb you can use  in certain situations. 00:09:46.750 --> 00:09:51.058 For example, on a clear sunny day you can use the Sunny 16 rule: 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. 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 00:10:02.819 --> 00:10:04.859 (on this camera, it would be 125). 00:10:05.360 --> 00:10:10.189 This works because a doubling in film speed  equals one stop in exposure - 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. 00:10:17.815 --> 00:10:22.365 If you need a faster shutter speed for a given shot, just open up the aperture 00:10:22.365 --> 00:10:25.280 an equal number of stops that you  increased the shutter speed to compensate. 00:10:26.080 --> 00:10:26.770 But, 00:10:27.015 --> 00:10:31.853 news flash, not every photograph is  taken outdoors on a sunny day. 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? 00:10:37.040 --> 00:10:38.980 Enter the light meter. 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. 00:10:46.004 --> 00:10:49.670 These devices were originally hand-held, and were fairly crude. 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.   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 00:11:00.480 --> 00:11:04.560 middle-grey in terms of brightness, then  you’d set your camera up appropriately. 00:11:05.280 --> 00:11:10.080 You can still buy handheld light meters today,  though they’ve been digitified of course.   00:11:10.080 --> 00:11:13.600 But before long they were integrated  into camera bodies themselves.   00:11:13.600 --> 00:11:18.913 And that’s why this otherwise mechanical camera  has a battery compartment. 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). 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.   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 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. 00:11:43.920 --> 00:11:48.432 The meter appears as a small display to the right  of the image in the viewfinder. 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. 00:11:53.683 --> 00:11:55.969 [clicky sounds of lens being attached] 00:11:55.969 --> 00:11:58.582 The small circle moved upwards. 00:11:58.582 --> 00:12:02.334 That circle is mechanically linked to  this little piece here. 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. 00:12:06.224 --> 00:12:09.517 This engages with a small peg on the lens itself. 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. 00:12:15.520 --> 00:12:19.294 Now, in addition to the ring, there’s a small  horizontal line. 00:12:19.294 --> 00:12:22.097 Right now it’s sitting in the bottom red area. 00:12:22.097 --> 00:12:27.041 This is actually a needle that will move depending on how much light the camera sees. 00:12:27.041 --> 00:12:29.731 And this is where the battery comes into play. 00:12:29.731 --> 00:12:34.107 You may have noticed this power switch - all that does is turn on the light meter. 00:12:34.107 --> 00:12:38.494 That little blue mark in the meter’s display is used as a battery level check. 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 00:12:44.193 --> 00:12:45.680 and the ASA to 100. 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 00:12:50.490 --> 00:12:53.396 and so long as it does - the battery’s OK! 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… 00:12:58.468 --> 00:12:59.659 we’ll get to that. 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. 00:13:05.085 --> 00:13:07.661 The brighter the image the higher it goes! 00:13:07.661 --> 00:13:08.800 But… 00:13:08.800 --> 00:13:11.155 where exactly is it measuring? 00:13:11.155 --> 00:13:15.168 You probably noticed the darker portion of the viewfinder towards the center. 00:13:15.168 --> 00:13:18.054 That is the sensitive area of the light meter. 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. 00:13:23.829 --> 00:13:26.821 But… how is that possible? 00:13:26.821 --> 00:13:29.020 Where is the actual sensor? 00:13:29.020 --> 00:13:32.807 Surely we didn’t have transparent light sensors in 1971. 00:13:33.360 --> 00:13:35.986 Well maybe we did but that’s not what’s going  on here. 00:13:35.986 --> 00:13:38.634 Again, it’s extremely clever. 00:13:38.634 --> 00:13:42.840 One of the many things you could customize on this camera  is the focusing screen. 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. 00:13:49.088 --> 00:13:52.648 And… there’s the focusing screen. 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… 00:13:58.641 --> 00:13:59.775 down at it. 00:13:59.775 --> 00:14:02.965 In fact all the viewfinder is is a prism, 00:14:03.280 --> 00:14:08.895 a roof pentaprism to be precise, there to redirect  your view from the eyepiece downard 00:14:08.895 --> 00:14:10.818 and flip the image horizontally. 00:14:10.818 --> 00:14:15.566 This creates the distinctive hump you see above the lens of all SLRs to this day, 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 00:14:21.349 --> 00:14:23.941 to the blobular designs of today. 00:14:23.941 --> 00:14:27.886 Anyway, this is the focusing screen and it, too,  is removable. 00:14:27.886 --> 00:14:33.225 Before I even remove it, though, something about it seems weird. 00:14:33.225 --> 00:14:36.727 That darker region appears to be… floating. 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. 00:14:43.192 --> 00:14:44.641 I’ll try my best, though. 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. 00:14:50.918 --> 00:14:55.081 If I pop the focusing screen out, you’ll get a clue as to why. 00:14:55.081 --> 00:14:58.179 See that little window there? Look through it. 00:14:58.179 --> 00:15:00.000 Weeeeird. 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. 00:15:08.368 --> 00:15:11.466 I really want to see how these were manufactured. 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 00:15:17.197 --> 00:15:20.967 and if we look from the front you’ll see what lies behind it. 00:15:20.967 --> 00:15:22.409 The light sensor. 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. 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, 00:15:36.091 --> 00:15:39.261 determine where the needle in the meter lands. 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   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. 00:15:54.770 --> 00:15:57.400 That’s what I call  neat. 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? 00:16:03.252 --> 00:16:05.478 You may very well have figured it out by now. 00:16:05.478 --> 00:16:10.208 This variety of meter is called a match-needle  meter, and that ring? 00:16:10.208 --> 00:16:12.116 Well, it’s your target. 00:16:12.240 --> 00:16:16.240 To use this camera’s light meter, you  first point the camera so that something   00:16:16.240 --> 00:16:20.080 in the scene that’s not too bright or too  dark is within that metering region.   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.   00:16:26.720 --> 00:16:31.120 Now, simply turn the aperture ring on the  lens until the ring surrounds the needle.   00:16:31.680 --> 00:16:34.255 You are now set to the correct exposure  setting 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! 00:16:39.191 --> 00:16:43.205 One exposure down, 23, maybe 35 more to go! 00:16:43.680 --> 00:16:46.401 But what if that combination isn’t what I want? 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. 00:16:52.707 --> 00:16:55.980 I’ll lose my sweet  sweet bokeh! 00:16:55.980 --> 00:17:00.965 Well, nothing a little after-the-fact AI-powered image processing can’t fix… I mean... 00:17:00.965 --> 00:17:02.398 that’s no problem at all! 00:17:02.398 --> 00:17:05.606 Simply adjust the shutter speed so that it’s faster. 00:17:05.606 --> 00:17:08.049 Aha! The needle moved. 00:17:08.049 --> 00:17:11.098 Here’s where the other  part of this genius system comes in. 00:17:11.440 --> 00:17:17.200 The actual sensitivity of the light meter itself is  affected by both the selected shutter speed   00:17:17.200 --> 00:17:19.184 and also the film speed. 00:17:19.184 --> 00:17:22.288 Perhaps you noticed this little insert in the shutter speed dial. 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. 00:17:29.448 --> 00:17:32.701 And the shutter speed alone has the same effect. 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. 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 00:17:44.344 --> 00:17:47.711 and then increasing the shutter speed by the same number of stops. 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. 00:17:52.882 --> 00:17:57.637 It also demonstrates the relationship between shutter speed and aperture beautifully. 00:17:57.637 --> 00:18:03.125 Each stop you move in shutter speed requires two clicks of the aperture ring to compensate. 00:18:03.125 --> 00:18:06.698 Two clicks because this lens has detents at half stops. 00:18:07.280 --> 00:18:14.202 Most elegantly, though? The matching nature  allows for shutter priority or aperture priority exposure. 00:18:14.202 --> 00:18:18.358 Rather than just point the camera at the scene and find a combo that works, 00:18:18.358 --> 00:18:22.800 you can fix one of those variables ahead of  time and adjust the other as needed. 00:18:23.360 --> 00:18:28.261 Say you want a stopped-down aperture  of F16 for a deep depth of field. 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.   00:18:34.800 --> 00:18:39.641 Or, perhaps you need a fast shutter speed to  freeze motion in action shots. 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. 00:18:45.644 --> 00:18:46.443 Easy! 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. 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,   00:19:00.640 --> 00:19:06.962 but there’s just something about the way  this works that is… beautifully elegant to me. 00:19:06.962 --> 00:19:08.871 Should we talk about the weirdness, though? 00:19:08.871 --> 00:19:10.240 Let’s talk about the weirdness. 00:19:10.960 --> 00:19:13.715 First, there’s a limit to its range of operation. 00:19:13.715 --> 00:19:17.253 Watch what happens as I approach a shutter speed of one second. 00:19:17.253 --> 00:19:20.587 At a quarter of a second, the meter turns red. 00:19:20.587 --> 00:19:24.657 It doesn’t exactly stop working, but it behaves erratically. 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. 00:19:30.356 --> 00:19:33.360 And here, at really slow shutter speeds, the needle just… 00:19:34.000 --> 00:19:36.767 stops changing at all even when it should. 00:19:36.767 --> 00:19:39.040 Now the meter is definitely not working right. 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.   00:19:43.680 --> 00:19:47.760 Changing the shutter speed setting simply  changes how sensitive the meter becomes.   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. 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. 00:20:00.800 --> 00:20:04.800 But the same thing needs to happen  when you increase the film speed.   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,   00:20:09.200 --> 00:20:12.077 so the needle needs to move one stop higher. 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.   00:20:19.120 --> 00:20:23.577 And the simplest way to do this? Just shift everything over. 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, 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. 00:20:36.640 --> 00:20:40.000 That’s exactly what changing  the film speed setting does,   00:20:40.000 --> 00:20:44.160 in fact that’s literally what it does because  we’re dealing with a mechanical contraption.   00:20:44.800 --> 00:20:50.160 Adjusting the film speed essentially relocates  the different sensitivities of the light meter   00:20:50.160 --> 00:20:53.571 independently of the camera’s shutter mechanism. 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. 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. 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. 00:21:15.560 --> 00:21:20.087 Each doubling of film  speed locks out the next lowest shutter speed. 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. 00:21:26.929 --> 00:21:31.765 Each doubling of light landing on the sensor makes it move the same distance upward. 00:21:31.765 --> 00:21:35.768 I imagine each sensitivity level is just  adding a different resistor to the mix. 00:21:36.000 --> 00:21:40.249 Which brings us to the next bit of weirdness: batteries. 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   00:21:46.640 --> 00:21:51.680 that the garbage can isn’t a magic receptacle  that makes things harmlessly disappear forever. 00:21:51.680 --> 00:21:56.468 The trouble is, mercury batteries produced 1.35  volts. 00:21:56.468 --> 00:21:58.874 That’s a weird voltage these days. 00:21:58.874 --> 00:22:03.647 While you can buy a replacement battery that fits  perfectly in the battery compartment, 00:22:03.647 --> 00:22:07.714 it will likely be a 1.5 volt alkaline battery. 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. 00:22:14.552 --> 00:22:18.742 The voltage matters a lot, and those batteries simply do not work. 00:22:18.742 --> 00:22:23.331 They push the needle way too high and it will never give you an accurate reading. 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. 00:22:28.659 --> 00:22:30.206 Trust me, I know. 00:22:30.206 --> 00:22:34.160 That same sort of error makes its way into every metering scenario. 00:22:34.800 --> 00:22:37.185 However, there is a solution! 00:22:37.185 --> 00:22:43.157 Zinc-air batteries, which produce electricity through reacting with oxygen in the air, are commonly available. 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,   00:22:49.040 --> 00:22:53.120 but they have a time-limited life  because you can’t stop the reaction   00:22:53.120 --> 00:22:55.548 once you remove the adhesive pull tab. 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. 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. 00:23:09.840 --> 00:23:14.316 Now, you can buy a zinc-air drop-in replacement online for  about $5 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. 00:23:19.959 --> 00:23:24.866 So, pro tip, get yourself some 675 hearing aid batteries. 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, 00:23:31.844 --> 00:23:35.687 a simple loop of wire insulation will center it well enough. 00:23:35.687 --> 00:23:38.675 You may need to bend the camera’s negative tab up slightly, 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. 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, 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. 00:23:55.840 --> 00:23:59.585 You might also have asked, where is  the meter’s display? 00:23:59.585 --> 00:24:01.579 And how is it lit? 00:24:01.579 --> 00:24:05.002 You can see it in the viewfinder quite clearly, but when you remove the viewfinder 00:24:05.002 --> 00:24:08.284 you find just a blank hole where it was. 00:24:08.284 --> 00:24:11.617 Well, the meter is actually right here. 00:24:11.617 --> 00:24:13.582 It’s tiny! 00:24:13.582 --> 00:24:16.880 And this piece of translucent plastic up here is what illuminates it. 00:24:17.440 --> 00:24:21.301 Old cameras are filled with all these clever,  intricate mechanisms. 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. 00:24:27.141 --> 00:24:28.897 Hmm, it’s amazing. 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 00:24:34.469 --> 00:24:38.611 this was never really super useful since the meter doesn’t work in low light anyway. 00:24:38.611 --> 00:24:41.792 For outdoor photography that little window works surprisingly well. 00:24:42.240 --> 00:24:47.207 Speaking of, did you notice the “OFF”  position on the meter is also marked “FLASH?”   00:24:47.760 --> 00:24:49.248 How does that work? 00:24:49.248 --> 00:24:51.259 Well, it doesn’t. 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 00:24:58.944 --> 00:25:01.991 based on film speed and distance to the subject. 00:25:01.991 --> 00:25:06.055 Oh, and that’s why the shutter speed 60 is marked in orange. 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 00:25:13.260 --> 00:25:15.881 and thus suitable for use with a flash. 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 00:25:23.163 --> 00:25:27.469 that any speed above 60 doesn’t expose the film all at once. 00:25:27.469 --> 00:25:30.756 This can actually create distortion in certain scenarios, 00:25:30.960 --> 00:25:34.868 so in a funny way, this old camera  has a rolling shutter. 00:25:34.868 --> 00:25:35.818 Go figure. 00:25:36.240 --> 00:25:41.600 The shutter mechanism alone is just  incredibly intricate and also fascinating,   00:25:41.600 --> 00:25:46.581 I mean the curtains themselves are made of  titanium. And they’re flexible! 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. 00:25:53.246 --> 00:25:55.525 You can see the seam right here. 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 00:26:02.519 --> 00:26:03.258 [CLICK] 00:26:03.258 --> 00:26:05.822 all done entirely mechanically. 00:26:05.822 --> 00:26:06.778 Amazing! 00:26:07.280 --> 00:26:09.600 This little thing here is  the old-style flash hookup,   00:26:09.600 --> 00:26:13.120 though up here by the film rewinder  you’ll find an older style of hot shoe.   00:26:13.840 --> 00:26:16.593 These little contacts here (along with those  inside the plug) 00:26:16.593 --> 00:26:21.392 are bridged right when the shutter is entirely open, signaling an electronic flash to… 00:26:21.392 --> 00:26:22.295 [CLICK] 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. 00:26:26.864 --> 00:26:31.676 I hope you enjoyed this look into the old-fashioned light metering systems of yesteryear. 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. 00:26:39.001 --> 00:26:43.295 But we’ve just scratched the surface  on how this camera takes pictures. 00:26:43.295 --> 00:26:46.700 What about the film itself? How does that store  an image? 00:26:46.700 --> 00:26:51.970 And what about film development? How do film negatives become printed photographs? 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. 00:26:59.380 --> 00:27:00.978 See you in the darkroom! 00:27:01.957 --> 00:27:03.976 ♫ logarithmically smooth jazz ♫ 00:27:04.384 --> 00:27:08.411 Single lens reflux(?), also sort… ahh already sca-rooooo-ewd it up 00:27:08.411 --> 00:27:11.414 and it’s great because I have to re-take the OTHER line, too! 00:27:11.414 --> 00:27:13.434 I don’ like how I said FUNdamental 00:27:13.434 --> 00:27:16.441 I forgot I need to.. Open that 00:27:16.441 --> 00:27:20.967 The more constricted that opening becomes. Thus, the let light… less light… 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) 00:27:26.322 --> 00:27:29.089 When a higher F number… ugh dang yeah forgot. 00:27:29.361 --> 00:27:31.288 Forgot the delivery! 00:27:31.451 --> 00:27:32.293 [clears throat] 00:27:32.293 --> 00:27:32.844 So… 00:27:34.668 --> 00:27:36.663 So… ble ble bah buh… we’ll move it over there. 00:27:36.663 --> 00:27:37.277 How ‘bout that? 00:27:37.604 --> 00:27:38.840 But nobody eberdy… 00:27:39.600 --> 00:27:42.695 nobody ebedy bedu… it’s going so well.... 00:27:42.695 --> 00:27:47.307 But, in 1974, the International Standards Association said… 00:27:47.307 --> 00:27:50.148 Organization! Dang it… 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" 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. 00:28:05.696 --> 00:28:12.563 Anyway language is dumb.