Recognizing focal lengths
Posted 28 October 2007 - 08:59 PM
Posted 29 October 2007 - 01:03 AM
Hi I'm trying to practice recognizing focal lengths used in movies so that I can better envision a shot and since I don't have access to a 35mm camera and lenses, watching movies is the only way to do it. I was wondering this: do you guys have any screenshots that you know were shot with a certain focal length or know of any movies that used only one or two lenses such that i might be able to pick them out while watching etc? or any other resources or ideas? thanks.
I'm not really sure that's possible, to be honest. A 32mm looks very close to a 35mm and a 35mm looks quite close to a 40mm. Worse yet, it gets even tougher on the long end of the scale. A 500mm looks surprisingly similar to a 1000mm unless you know the actual subject distance.
Why do you need to know the exact focal length of a particular shot, anyway? Wouldn't it be more useful to you to know what lenses look like in terms of wide, normal, long, really wide, et cetera? After all, learning to recognize the focal length in terms of the format would give you the experience of recognizing the actual qualities of that type of lens, not just a number.
Edited by Chris Keth, 29 October 2007 - 01:05 AM.
Posted 29 October 2007 - 01:52 AM
Posted 29 October 2007 - 02:13 AM
Go the cheap route. Get a 35mm SLR camera and get familiar with various focal lengths.
Well, a DSLR would be even better since the sensor size is the same as a 35mm movie frame, so the focal lengths are similar, as opposed to an 8-perf 35mm still camera frame.
You can look at a few historical examples, though you have to factor in things like masking -- for example, a lot of the wide-angle shots in "Citizen Kane" were done with a 25mm lens and Ozu was famous for shooting whole movies on a 50mm lens, but those were 1.37 Academy movies, so the same lens image would be cropped vertically in 1.85 projection in modern movies and thus feel slightly longer.
"Bottle Rocket" was mostly shot on a 27mm lens and "Rushmore" was mostly shot on a 40mm anamorphic lens. So was "Chinatown".
Many wide-angle shots in "Touch of Evil" used an 18mm lens.
Posted 29 October 2007 - 04:30 AM
There are a few directors who only use a limited amount of lenses. People like the Cohen Brothers, Terry Gilliam, Jean-Pierre Jeunet and Tim Burton seem to stay on the wider end most, if not all, of the time.
I once worked on a feature of a friend as script supervisor. I made it a game to guess the focal lenghts by just looking at the monitor and then checking with the 2nd AC. I was about right 50% of the time, but keep in mind that I knew the size of the location, what focal lenghts we carried, etc...
Posted 29 October 2007 - 02:32 PM
Edited by cal bickford, 29 October 2007 - 02:34 PM.
Posted 29 October 2007 - 05:07 PM
Thanks for all the info so far, any more guys?
Start simple. First maybe just try to break it down into focal ranges. I still think of shots that way -- wide, medium-wide, normal, medium-tight, and tight (<25, 35, 50, 85, 100+ in 35mm terms). That's much more useful from a storytelling standpoint anyway, so that the audience can distinguish a change in shot size easily. On set you'll get more particular with slight adjustments in focal length for more practical reasons.
One common approach to filmmaking is to tell the bulk of a scene with the camera at a consistent distance from the action, so that the lens changes create the changes in shot size (master on a 25mm , two-shot on a 50mm, and singles on an 85). But that's just one very simple, rudimentary approach.
Typically closeups ("singles") are done at a focal length that's "medium tight" or around 85mm in the 35mm format. This is usally the most flattering on the actor's face by avoiding any wide-angle distortion, and you get a shallower depth of field for that shot (where you want the audience's attention focused on the character at that moment anyway). But again, this is only a basic approach. Some filmmakers get a distinct feel and presence of the action by bending this "rule" and getting the camera much closer, with shorter focal lengths (or by doing the opposite, with really long lenses).
Oh, and also pay attention to the point of view that's suggested by the combination of focal length and distance to subject. Filmmakers often use the camera to shift the point of view for narrative purposes, like suddenly coming close for a single to put us in the character's space, or creating a sudden omniscient p.o.v. by moving the camera farther away.
There are no consistent rules between filmmakers, yet a good film has its own distinct visual language or grammar. Maybe take one film at a time, and look for the pattern of focal length to shot size. You'll find that the rules or language of one film often don't apply to another.
You might want to check out these books: