# Technical movie questions. **URL:** \ **Category:** Cafe Society\ **Created:** [January 17, 2006, 8:13pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401 "2006-01-17T20:13:55Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [January 17, 2006, 8:13pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/1 "2006-01-17T20:13:55Z")
I pretty much NEVER watch DVD commentaries, but this weekend I turned it on accidently while watching _Serenity_. I sort of got instantly hooked, and I went back and watched almost the entire movie with the commentary which increased my appreciation for this film which I thoroughly enjoyed. Anyway. . . Wheedon was talking about 2 things I have a question on. I paraphrase. 1. “Here, I used a 14 which made the tunnel seem like the longest tunnel in the history of the world which was cool. But when he came out of the tunnel, the other characters looked like they were 4 miles away.” So, what’s the “14”? What is typical? What’s it a measure of? What the analogous thing with a camera, a “wide angle lens”? 1. “Here I used 120 (maybe “speed 120”). It gives it that detailed, almost grainy look. In a movie like Gladiator, they used a 40 where you could see every grain of sand kicked up but I didn’t want to go that low.” Again, what’s ‘120’? Is is the “exposure time” of the film? Meaning a shorter time lets in more light so you see ALL of the detail? I thought all film travelled at a specific speed, so he’s not talking about ‘frames per second’ which I understand to be a constant, 28 frames per second. Thanks, I know there’s a couple film guys here (Johhny LA and CandidGamera and ???) ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [January 17, 2006, 8:22pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/2 "2006-01-17T20:22:53Z")
> [@Trunk](#): > > I pretty much NEVER watch DVD commentaries, but this weekend I turned it on accidently while watching _Serenity_. I sort of got instantly hooked, and I went back and watched almost the entire movie with the commentary which increased my appreciation for this film which I thoroughly enjoyed. > > Anyway. . . > > Wheedon was talking about 2 things I have a question on. I paraphrase. > > 1. “Here, I used a 14 which made the tunnel seem like the longest tunnel in the history of the world which was cool. But when he came out of the tunnel, the other characters looked like they were 4 miles away.” > > So, what’s the “14”? What is typical? What’s it a measure of? What the analogous thing with a camera, a “wide angle lens”? A long lens–a telephoto–shot from a great distance, will make the distance between objects in line with the lens appear smaller. Think of it this way: if you’re 10 feet from someone, and there’s a house 10 feet behind them, the distance between them and the house is 100% of the distance between the camera and the person. If you’re 100 feet back, but using a lens to make them LOOK closer, the distance between them and the house is now 10% of the distance between you and the person. The house “looks” closer. This is why they usually show a guy being chased by a car from in front, through a telephoto. Heightens the sense of danger. > [@Trunk](#): > > 1. “Here I used 120 (maybe “speed 120”). It gives it that detailed, almost grainy look. In a movie like Gladiator, they used a 40 where you could see every grain of sand kicked up but I didn’t want to go that low.” > > Again, what’s ‘120’? Is is the “exposure time” of the film? Meaning a shorter time lets in more light so you see ALL of the detail? I thought all film travelled at a specific speed, so he’s not talking about ‘frames per second’ which I understand to be a constant, 28 frames per second. Yes, the speed of the film affects the graininess. The faster most films, the finer the grain. (There are nonconventional film stocks that aren’t part of the same scale.) [/QUOTE] ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [January 17, 2006, 8:30pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/3 "2006-01-17T20:30:12Z")
Can you explain what the numbers mean? Is “14” a lens diameter, a zoom multiple? What’s ‘40’ vs. ‘120’. Is it just enough to know that “40 is fast” and “150 is slow”? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 17, 2006, 9:27pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/4 "2006-01-17T21:27:55Z")
> [@lissener](#): > > Yes, the speed of the film affects the graininess. The faster most films, the finer the grain. (There are nonconventional film stocks that aren’t part of the same scale.) Just the opposite. Fast films have larger grain size. Something like 25 ASA Kodachrome that needs to be shot at high noon on a clear day can be enlarged to gigantic amounts and not show grain, whereas something like 800 ASA film which might let you shoot a portrait lit by one or two candles looks like beach sand, even at a 4x6" print. With motion picture film, you really can’t adjust the exposure time like you can with an SLR - it’s shot at 24 frames per second, but I don’t know what the effective shutter speed is. 14 might be the focal length of the lens, usually expressed in millimeters. With 35mm SLRs, a 14 would be an extreme wide-angle, if not an outright fisheye. 120 might be the name of the film stock, such as Kodak 120. Just a WAG here. Scratch that. I just had a look, and Kodak’s films are either given 4-digit names, or names like “Vision 2” Fuji’s films get names like Eterna or Reala. ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [January 17, 2006, 11:05pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/5 "2006-01-17T23:05:22Z")
> [@gotpasswords](#): > > Just the opposite. Yeah. Duh. My brain and my typing fingers are apparently not speaking today. ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [January 17, 2006, 11:53pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/6 "2006-01-17T23:53:27Z")
> [@gotpasswords](#): > > 14 might be the focal length of the lens, usually expressed in millimeters. With 35mm SLRs, a 14 would be an extreme wide-angle, if not an outright fisheye. Hmm… and given what **lissener** mentioned in regards to a long lens making things in the background seem closer to the subject, a 14 would likely be a wide angle lens for a movie camera too. ISTR back when I was watching Babylon 5 on TNT and reading JMS’s commentary about it on the Lurker’s Guide, he mentioned a cool trick you could do with a zoom lens where where you zoomed out with the lens while moving the camera closer to compensate. The end result was that the subject would get a little bit closer, and the background would seem to warp away behind him. ---
**Author:** ![Hodge](https://avatars.discourse-cdn.com/v4/letter/h/5f9b8f/32.png) [@Hodge](https://boards.straightdope.com/u/Hodge)\ **Post date:** [January 18, 2006, 12:06am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/7 "2006-01-18T00:06:43Z")
I think **gotpasswords** has it right. The 14 probably refers to a 14mm lens which is a very wide-angle focal length. And, just as telephoto lenses seem to compress distances (per **lissener’s** explanation above), wide-angle lenses appear to stretch or exaggerate distances. I’m not sure about the 120, though. 120 is a medium-format film size capable of higher resultion than 35mm but I seem to recall discussions about _Gladiator_ revolving around film speed to achieve its affects. ---
**Author:** ![Gangster\_Octopus](https://avatars.discourse-cdn.com/v4/letter/g/a8b319/32.png) [@Gangster\_Octopus](https://boards.straightdope.com/u/Gangster_Octopus)\ **Post date:** [January 18, 2006, 12:21am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/8 "2006-01-18T00:21:05Z")
40 and 120 refer to the shutter speed, meaning, for example the shutter is open for 1/40th versus 1/120th of a second. ---
**Author:** ![Walloon](https://avatars.discourse-cdn.com/v4/letter/w/fbc32d/32.png) [@Walloon](https://boards.straightdope.com/u/Walloon)\ **Post date:** [January 18, 2006, 12:37am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/9 "2006-01-18T00:37:12Z")
50mm is the normal focal length of a lens on a 35mm camera. A lower number is a wide-angle, a higher number is a telephoto. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [January 18, 2006, 12:55am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/10 "2006-01-18T00:55:40Z")
> [@Raguleader](#): > > ISTR back when I was watching Babylon 5 on TNT and reading JMS’s commentary about it on the Lurker’s Guide, he mentioned a cool trick you could do with a zoom lens where where you zoomed out with the lens while moving the camera closer to compensate. The end result was that the subject would get a little bit closer, and the background would seem to warp away behind him. A good effect, but not new. _Vertigo_, _Jaws_ and _Goodfellas_ all had famous scenes that used some variation of that technique. ---
**Author:** ![Quint](https://avatars.discourse-cdn.com/v4/letter/q/76d3ee/32.png) [@Quint](https://boards.straightdope.com/u/Quint)\ **Post date:** [January 18, 2006, 5:26am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/11 "2006-01-18T05:26:27Z")
The 14 is definitley a 14mm lens. Quite wide angle, and a standard prime lens used in filmmaking. The equivalent in 35mm stills photography would be (very) roughly a 28mm lens. Unless they were shooting anamorphic. As far as the 120 vs 40 question goes, there are two possibilities. 1. This is in reference to the ASA (or speed) of the film used. While this is possible, as both of these numbers can refer to film speeds (120 would more likely be called 125, but both can be used) and 40 would offer more detail, it doesn’t fit the quote. If “graininess” was the goal they would use faster film (like 500ASA) or possibly push something slower one or two stops (rate it faster and leave it in “the soup” longer at the lab). So, it’s almost certainly: 2)A reference to the shutter angle used. A typical motion picture camera uses a 180 degree shutter at 24 frames per second, yeilding a shutter speed of roughly 1/50th of a second. In _Gladiator_ a lot of smaller shutter angles were used, and at a 40 degree shutter you would have an effective shutter speed of roughly 1/200th of a second at 24 frames per second. This reduces motion blur. A grain of sand flying through the frame at 1/50th shutter speed would be a streak, as the sand would cover some distance in that time. At 1/200th shutter speed the grain would be caught moving far less distance, and would consequently appear much sharper in the final product. So in _Serenity_ they used a 120 degree shutter which would give an effective shutter speed of roughly 1/70th a second, lessening motion blur somewhat, but not as much as in _Gladiator_. ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [January 18, 2006, 12:35pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/12 "2006-01-18T12:35:18Z")
**Quint** , your #2 sounds like what he was describing. I guess I didn’t mean “graininess” in the true sense. It was the more like that effect of being able to see individual grains of sand flying in the air during a fight sequence. And, yes, he was going for “somewhat” of that effect, but didn’t want the whole hog. So, is that a modern technique? I don’t recall seeing that kind of stuff before Gladiator, but I’ve seen it everywhere since. However, I could have just missed it before Gladiator, or they used it in ways that I didn’t notice. Peter Jackson used it a bit in LOTR. Also, focal length is most definitely what he was referring to with the 14. He was actually looking through one of those handheld things to frame it, not through an actual camera. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [January 18, 2006, 3:55pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/13 "2006-01-18T15:55:01Z")
> [@Gangster Octopus](#): > > 40 and 120 refer to the shutter speed, meaning, for example the shutter is open for 1/40th versus 1/120th of a second. As others have said, these numbers would be film ‘speed’ ratings if the show is shot on film. My _American Cinematographer Manual_ is the 7th Edition, so it’s a bit old. It doesn’t list any 40 or 120 film. There’s 25, 50, 64 and 125, but no 40 or 120 that I can see. On the other hand, my 24p DV camera does have 1/40 sec. and 1/120 sec shutter speeds. Film cameras traditionally operate at 24 frames per second (25 fps in Europe). They traditionally have 180° shutters. (i.e., the shutter is a disc that it half open and half solid.) So 24 fps exposed for half of the time equals an exposure time of 1/48 second. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [January 18, 2006, 3:56pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/14 "2006-01-18T15:56:49Z")
:smack: See what I get for not reading the whole thread before posting? **Quint** already covered the shutter thing. (Good thing I stopped typing before I went too far.) ---
**Author:** ![Gangster\_Octopus](https://avatars.discourse-cdn.com/v4/letter/g/a8b319/32.png) [@Gangster\_Octopus](https://boards.straightdope.com/u/Gangster_Octopus)\ **Post date:** [January 18, 2006, 5:07pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/15 "2006-01-18T17:07:42Z")
> [@Trunk](#): > > **Quint** , your #2 sounds like what he was describing. > > I guess I didn’t mean “graininess” in the true sense. > > It was the more like that effect of being able to see individual grains of sand flying in the air during a fight sequence. > > And, yes, he was going for “somewhat” of that effect, but didn’t want the whole hog. > > So, is that a modern technique? I don’t recall seeing that kind of stuff before Gladiator, but I’ve seen it everywhere since. However, I could have just missed it before Gladiator, or they used it in ways that I didn’t notice. Peter Jackson used it a bit in LOTR. > > Also, focal length is most definitely what he was referring to with the 14. He was actually looking through one of those handheld things to frame it, not through an actual camera. Ridley Scott used the same technique in _Black Hawk Down_ although I cannot remember which move came first. ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [January 18, 2006, 5:29pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/16 "2006-01-18T17:29:07Z")
> [@Gangster Octopus](#): > > Ridley Scott used the same technique in _Black Hawk Down_ although I cannot remember which move came first. Yeah, I think you saw it in Soderbergh’s _Traffic_ and in Jackson’s _LOTR_ (I’m imagining horses kicking up dirt). When you’re not actually capturing something like dirt, it gives it that “hyper realistic” look, for lack of a better description. I forget why Wheedon said he used it. . .maybe for more “immediacy” but maybe more for an “anti-septic” look. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [January 18, 2006, 6:16pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/17 "2006-01-18T18:16:22Z")
> [@Raguleader](#): > > ISTR back when I was watching Babylon 5 on TNT and reading JMS’s commentary about it on the Lurker’s Guide, he mentioned a cool trick you could do with a zoom lens where where you zoomed out with the lens while moving the camera closer to compensate. The end result was that the subject would get a little bit closer, and the background would seem to warp away behind him. This is colloqually referred to as a “trombone” or zoom & track shot; [here](http://www.imdb.com/Indie/Ask/20021028.html)’s an explaination of it (look in the third column). As **Robot Arm** says, it’s widely used today–many digicams actually have a setting that will do this automatically–and although Hitchcock used it widely (most memorably in _Vertigo_ to impart the sense of, well, vertigo) I don’t believe he was the first to utilize it. Personally, I like the late John Frankenheimer’s commentary on _Ronin_–it’s basically a primer of how to film an action/thriller. Stranger ---
**Author:** ![Trunk](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@Trunk](https://boards.straightdope.com/u/Trunk)\ **Post date:** [January 18, 2006, 8:04pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/18 "2006-01-18T20:04:18Z")
> [@Stranger On A Train](#): > > This is colloqually referred to as a “trombone” or zoom & track shot; [here](http://www.imdb.com/Indie/Ask/20021028.html)’s an explaination of it (look in the third column). > > As **Robot Arm** says, it’s widely used today–many digicams actually have a setting that will do this automatically–and although Hitchcock used it widely (most memorably in _Vertigo_ to impart the sense of, well, vertigo) I don’t believe he was the first to utilize it. > > Personally, I like the late John Frankenheimer’s commentary on _Ronin_–it’s basically a primer of how to film an action/thriller. > > Stranger Thanks for that tip, Stranger. I think that early in the days of DVD, I tried to listen to some commentaries, and totally gave up. But I found this one by Wheedon fascinating. I just couldn’t believe how well thought out every aspect of the movie was, how complementary he was of set design, music. He seemed to be aware of every detail of every shot, and either had notes with him, or had terrific recall of the filming. I really like _Ronin_ and I think I’ll have to check that out. ---
**Author:** ![Quint](https://avatars.discourse-cdn.com/v4/letter/q/76d3ee/32.png) [@Quint](https://boards.straightdope.com/u/Quint)\ **Post date:** [January 18, 2006, 8:14pm UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/19 "2006-01-18T20:14:37Z")
> [@Trunk](#): > > It was the more like that effect of being able to see individual grains of sand flying in the air during a fight sequence. > > And, yes, he was going for “somewhat” of that effect, but didn’t want the whole hog. > > So, is that a modern technique? I don’t recall seeing that kind of stuff before Gladiator, but I’ve seen it everywhere since. However, I could have just missed it before Gladiator, or they used it in ways that I didn’t notice. Peter Jackson used it a bit in LOTR. The film that brought it to modern prominence was _Saving Private Ryan_ where a 45 degree shutter was used to great effect in the invasion sequence. The DoP Janusz Kaminski [explains:](http://www.sproe.com/s/spr.html) “In this way, we attained a certain staccato in the actors’ movements and a certain crispness in the explosions, which makes them slightly more realistic.” I think the use of this technique falls under the “everything old is new again” category. Movie cameras dating back at least as far as [1909](http://www.theasc.com/clubhouse/inside/beg.htm) have had variable shutters, meaning you were not married to a 180 degree shutter. There is no doubt in my mind that this effect was used, as the variable shutter was a feature on virtually every major non-sync sound camera in production for almost 100 years. My suspicion is that, much like other interesting camera techniques, it’s use was halted in studio films by the advent of sound, and was forgotten about or deemed “unnatural” over the years. I have absolutley no proof for this assertion, however. In documentaries and newsreel footage I would be shocked if smaller shutter angles were not used, and I think it would be foolish to suggest that the cameramen using the smaller angles were unaware of the effect this would have. ---
**Author:** ![Quint](https://avatars.discourse-cdn.com/v4/letter/q/76d3ee/32.png) [@Quint](https://boards.straightdope.com/u/Quint)\ **Post date:** [January 19, 2006, 5:20am UTC](https://boards.straightdope.com/t/technical-movie-questions/340401/20 "2006-01-19T05:20:15Z")
Just came back to curse **Stranger on a Train** ’s name. I’ve never seen that column you linked to before, so there is an entire _archive_ of Q&A with _Oliver Stapleton_(!) to be read. Didn’t clean the apartment this afternoon, much to the aggravation of the missus. As if the SDMB lurkathon I’ve been on wasn’t enough. :smack: [Next page](https://boards.straightdope.com/t/technical-movie-questions/340401.md?page=2)