The appearance of continuity in motion pictures results from the persistance of vision of the eye which is longer than the time between frames.
Jeez, I always seem to come in late to these threads! (And I’m posting without the benefit of caffeine at the moment, to boot.)
That the cinematographer is doing is playing with telephoto distortion. When using a long lens, the background appears to be “compressed” into the foreground. Wide angle distortion has the opposite effect. Short lenses cause the background to recede. This is most clearly seen in “fisheye” shots.
You also need to think about Depth of Field. In actuality, there is only a single plane that is truly in focus; but with a wider depth of field, we percieve a greater range of the shot as being in focus. That is to say, your subject will be in focus and a certain distance before and behind him will also appear to be in focus. The smaller the aperture, the greater this “in-focus” range is. But being a balancing act, the more light you need in order to achieve the proper exposure. With low light you need a larger aperture for a given film, and the depth of field is smaller.
Exposure can be manipulated in a number of ways. You can increase the available light and reduce the size of the aperture or vice versa. You can vary the shutter angle to compensate for greater or lesser amounts of light. You can choose faster or slower film stocks which are suitable for lesser or greater amounts of light. If you have a surplus of light, you can use neutral density filters and/or polarizers. For black and white film, you can use various coloured filters for different effects. (A red filter will make a blue sky look black, for example.) You can vary the camera speed to increase or reduce the exposure. (For example, night shots that don’t have any movement can be shot at slower speeds so that they are exposed properly but things won’t be zipping around the frame.)
I was going to say this!
I’ve been wanting to try this. My NPR’s shutter can close down to 5°.
Add 25 to that list. PAL is 25 frames per second and AFAIK quite a few European movies are shot at 25 fps.
I think the minimum frame rate for persistance of vision to work is 16 frames per second. Many regular-8 cameras used 16fps as their standard speed. Super-8 cameras use 18fps as their standard. I’ve heard that this is because the sound strip works better at that rate; but sound film came out later than super-8, so I wonder. Many super-8 cameras also run at 24 fps, which is tha American standard rate. In Europe, professional equipment is often set to run at 25fps. This is handy for telecine, since they use 50hz on their electrical mains.
Speaking of frame rates (and edging away from the OP), people have asked about “scroll bars” when filming televisions and monitors. What is happening there is that the shutter is not exposing the same amount of the monitor in each frame, which leaves an underexposed “stripe”. If you are using a 24fps camera to shoot a U.S. television, you need to adjust your shuttle angle to 144°. (Most shutters were not adjustable until you got to very expensive cameras. The Eclair NPR, introduced in 1960, has a shutter that can be set to 145° which is usually close enough.) Cameras used to have motors that were “wild” or perhaps electronically controlled. In order to keep the sound in synch with the image, there was a cable that ran from the camera to the sound recorder. The camera or an accessory would generate a 60hz tone that would be recorded on one track of the tape. The tape would be resolved onto “full coat” or “mag film”, which is 16mm (or 35mm, depending on what you’re shooting with) film that is completely covered with a magnetic emulsion. Once resolved onto mag film, you have a one-to-one frame correspondence between the film and the audio which is kept in synch by using a sprocketed “synch block”. The 60hz tone on the tape was (is) used to regulate the speed of the resolving machine so that the mag film is the same length as the image film. Today, cameras and audio recorders have motors that are regulated by a quartz crystal. The camera runs at exactly 24fps, and the recorder also keeps its regulated speed that will result in exactly 24fps sound when the tape is transferred to full coat. And in case you’re wondering, the slate – or “clap board” – is used to produce an image of something making noise so that the image and sound has a start point for synchronization.
Anyway, crystal motors can usually accept a “milliframe controller”. This is a device that allows the operator to set the frame rate to within one one-thousanth of a frame per second. You can set the speed of the camera to match the refresh rate of any monitor and eliminate the scroll bar.
True. “Strobing” isn’t really the right word for the effect I meant. Think of footage of fast-moving sports. Often you will be able to see moving objects, such as a ball, “jumping” from one place to another between frames. This is because, although the frame rate is fast enough to give the effect of a continuous picture, the shutter speed is short enough to “freeze” the ball in one position on each frame. The plus side, obviously, is that it gives a sharp freeze-frame, but when watching at normal speed it can be kind of annoying.
The whole thing is about the distinct visual difference between moving closer to an object and simply zooming in upon it with a camera - an elephant directly in front of you can block your view of an entire skyscraper, but stand a hundred yards back and the elephant is dwarfed by the building.
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- It’s been noted, but one way is to move the camera closer while zooming “out” at the same time.
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- The other way is to use two stacked lenses or a compound lens that has two variable “power” adjustments–on both the front and back end. At first both ends are adjusted for a long focal length, giving a deep field of view (detailed foreground, subject and background) but when both lenses are adjusted to a short focal length at the same time, the overall magnification of the whole set of lenses doesn’t change–but the depth of field becomes very narrow, and only the subject centered in it stays in focus.
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I’m gettin’ hives. 
Nicely done, Johnny, DougC and Mangetout.
True, that Vertigo made use of this effect first. ( Or, at least, first that we are all aware of ). Didja know that the infamous “Vertigo Shot” is a model of the bell tower steps, turned on its side and shot as a special effects shot?
Jaws made ample use of it, as did the other films named. The most dramatically servile use of the effect in recent memory to me, is the scene in Scorcese’s GoodFellas, where DeNiro has just found out that Joe Pesci is no longer amongst the living. He re-enters the diner and sits down across from Ray Liotta. VERY slowly the camera moves in opposite motion to the direction of the zoom lens. It’s brilliant use of the idea. Just as DeNiro’s character ( Jimmy? Joey? Johnny? ) is trying to absorb the shock and his mind is reeling, we are served up a most useful visual cue to this inner turmoil.
Scorcese is one to use such effects sparingly, and with great impact. Unlike Spielberg, Scorcese doesn’t make use of such angles and shots ad nauseum.
Spielberg’s signature meanacing shot is below eyeline, and off to one side about 10 degrees. Dolly in quickly, boom up as the camera is angled off a bit more, so there is a pan in there with the boom. You’re all of a sudden given a lovely shot up the nostrils, accentuating the jawline and eyes.
I used to do the Perspective-Shifting Zoom/Moving shot on music videos, if we had a zoom lens up on the Steadicam. Now and then I’d try to sell it on a videotape shoot- usually a live musical event. It’s simply not appropriate for normal t.v. production fare; it’d jump out at you too much. But it was always fun to play around with in rehearsals. Doubly so when there were steps or a ramp available, so I could do the zoom out/ walk in on a diagonal.
Funny thing about shutter angle/frame rate/depth of field. Here’s the problem. If you pull iris during a shot on a film camera to compensate for a change in exposure, it is radically apparent. Your depth of focus shifts during the shot, it is sacrificed at the altar of exposure. With the advent of the Arriflex 535, 535B and 435 and 435ES, you were offered the chance to solve this problem in a whole new way.
You could program in calculated change in exposure, and instead of the iris being opened or closed, the SHUTTER leaves on the camera’s body would be altered. Instead of a standard 180 degree shutter, where you have A) a butterfly of two 90 degree openings, or B) a half-circle of black metal, you could have that amount of exposed film time altered by changing the degree of shutter opening. As mentioned up there somewhere, when shooting t.v. monitors ( NTSC, at least ), you want to go for 144 degree shutter, to eliminate the retrace lines commonly called Roll Bars.
Adjusting the shutter to compensate a light change in the shot means that you have not touched the iris in the lens’s rear area- and therefore have not altered the depth of focus.
One of the early sequences that made amazing use of this was in Dracula, directed by Coppola. Michael Ballhaus was the Director of Photography, and the first person in the USA to own his own Arriflex 535. It was a new system then, and Ballhaus made ample use of the technology described above. There is a brilliant scary point of view sequence of what seems to be the eyes of a dog, or wolf, prowling around the gardens and back steps behind the mansion. The camera shifts speeds, and of course if you shift frame rates you must compensate somehow. Instead of an iris pull, there were shutter pulls.
David Simmons is correct in his assertions concerning dept of focus and high light levels in Citizen Kane. This is no longer an issue. While you COULD use high light levels and a high aperture setting, it is very much more the norm to use a split diopter to achieve this effect. The HBO series Six Feet Under is a recent fan of this effect, using it both in car shots and in standard interiors. ( It could be used on an exterior, but in a brightly lit exterior, you’ve got gobs of depth of field anyway. )
Years ago, in Central Park, I had to pack in a LOT of Neutral Density filters on the camera on my Steadicam, because the D.P. insisted on very shallow depth of field, and we had a blazingly bright sunny day. Anyway, the deep focus look was helped along at various points. For Kubrick’s 2001: A Space Odyssey, he made use of lenses normally not mounted to film cameras, ones that had an enormously larger range from wide open to shut down. Similarly, in Barry Lyndon in the now-infamous candlelit shots, he was shooting at roughly an f .8 . Now, that’s wide open and hopin’ !
r_k’s mention of the strobing brings up another point. It is very common today on live television events to make use of the high speed shutter settings in the broadcast cameras. Video is shot at 30 frames a second ( more or less. ) The shutter is typically 1/50th- not very fast. Your average normal SLR still camera’s favorite setting is 1/60th of a second. It will freeze slow movement, but all else blurs.
However, if you have tons of light, you can crank up the electronic “shutter” way into the scary ranges of 1/1,000th of a second or better. At these speeds, you have that remarkable effect seen at the kyaking event at the Atlanta Olympic Games. Each spatter of water and flash of oar is perfectly sharp. A slow-mo replay of any bit of the event renders absolutely clear sharp images, with no blur from extreme motion of either water or athlete. Similarly, when well enough lit, such things as track and field and such, are given the highspeed treatment- so that playback in slow-mo is more articulate and easily seen.
In the film world, there are ways to make sure that every frame looks as though it was a photograph taken with a strobe flash- they’re strobing units that are slaved to the motion picture camera, and flash in synch with the shutter. There was this 7-Up commercial that was the first biggie to make use of this neato toy.
To turn to Nerrie’s O.P. again for a moment, there are other ways to get the effect of moving rapidly through space. But, the ones I’ve elaborated upon and the method of doubled lenses described very well by DougC really are the two most popular methods- both are done IN-camera, and on-set.
If one wants to get fancypants, one designs a shot that appears to be totally seamless, starting a mile or two off the shoreline in Miami, and winds up at the edge of the stage in a nightclub, all in one “shot”.
The movie The Bird Cage had this opening- it was much the stuff of discussion over on the Steadicam Operator forum I frequent. It was revealed by the fellow who shot it, that it was three shots.
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Helicopter shot using a WesCam ball, or similar gyrostabilized camera. Camera swoops in, over water, over beach, to the street, and down.
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Steadicam Operator is standing high on a crane. Crane moves down and forwards at once, and Operator steps off the crane without a hitch ( no mean feat ), and moves up the steps of the nightclub. The doors open as the camera sweeps in…
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The camera continues in, and up to the stage…
Shot 1 was morphed into the opening frame of Shot 2- Shot 2 was framed to match Shot 1 closely, by using stillstore playback on set, of the final moments of the helicopter shot.
Shot 2 was performed, and finished- on location in Miami.
Shot 2 morphs into Shot 3, shot on a soundstage in L.A. Again, the Operator is matching ending framing to starting framing, knowing that the shots must overlap perfectly for long enough for a clean morph to be done. It was a tasty sequence.
Johnny, that N.P.R. can close down THAT far??? Gosh- you oughta shoot some stuff at that range, that’s the hairy edge of exposed frame. Time lapse, moving car stuff, subways, whatever. Very cool…
Cartooniverse
Yup. Acorrding to the operation manual, the shutter opening is variable between 5° and 180°, at ten degree incriments between 10° and 180°. I have only used 180° though. Never needed to use anything else, and I used to use a Sekonic L-398 when I got the camera. Being lazy, I picked up a Minolta IV-F a few years ago that will make it much easier for my lazy ass to find the proper exposure at really narrow shutter openings.
Hey, check my math here… If I’m shooting at 24fps with a 5° shutter, that’s roughly 1/1600 second; right?
I realize that you are directing your question to Cartooniverse, But FWIW your math is “roughly” correct. Shooting 24fps with a 180 degree shutter gives you a 1/50 second exposure. (1/48th for nit-pickers) Each subsequent halving of the shutter angle halves the time the film is exposed to light. So at 90 degrees it’s 1/100 second, 45 gives 1/200, 20 = 1/400, 10 = 1/800, and 5 = 1/1600.
Is this exactly correct? No. But the difference will certainly be within acceptable tolerances for modern film stocks and can easily be corrected with timing lights or during telecine transfer.
God, Coven, welcome to the Straight Dope !!!
You said two phrases to warm the heart. "Timing lights " and “telecine transfer”.
Johnny may have been answering a post of mine, but it is simply the nature of SDMB that all posts are fair game for all Dopers. Glad you jumped in. 
And, I still have my old analog Spectra Pro… WITH the special Red Highspeed Film calibration numbers !!
I used to think that Spielberg had invented the shot in Jaws, until I read about Hitchcock using it in Vertigo. I was puzzled, because I had seen Vertigo, and didn’t recall a similar shot.
But the next time I saw it, I realized Hitchcock used it in a completely different way: first, very rapidly, like a second or less, and secondly, it’s looking down the interior of the bell tower, and it’s a POV shot intended to convey the fear of heights Jimmy Stewart’s character is feeling. But to me it looked more like a trick telescoping set, rather than a lens/camera move effect.
Speilberg’s use is much slower, and is looking at Scheider (i.e. not a POV). So although it also conveys his emotional state, it does so in a much more subtle (and, I think, effective) way. I think Speilberg has a claim to have reinvented and significantly expanded on Hitchcock’s idea.
All uses I’ve seen since then have been minor variations on Speilberg’s technique. And I don’t recall seeing a Hitchcock-like use.
Does anyone know of a use of the shot between Vertigo and Jaws?