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Mark Allen
Director , Screenwriter , Composer
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Cinematography Made Easy 02

In part two I'm going to continue with some technical terms. Frame Rate:   This is a tricky topic because in theory it's very simple, but there is are two often misunderstood factors...  so let me just dive in:Film is 24 fps (frames per second)TV using PAL (Europe) is 25 fps TV using NTSC (US)  is 29.97 fpsWeb is ANYTHINGSee frame rate depends on the delivery system, the web can playback whatever you give it.  Projectors are set to 24 fps historically (IMAX is 60 by the way).And you may have noticed there is one weird number in there.... 29.97?   Well, there is a technical historical reason, but to keep this short let's say this.  It was supposed to be 30 fps, but in order to allow for audio it became 29.97.  To make matters worse, people will often say 30 instead of 29.97.  And now I have to add in the other weird thing.... INTERLACING.... you see... TV traditionally isn't actually 29.97 frames per second.  It's actually 59.94 Fields per second.A field is every OTHER line on your tv screen.  So in fact, you're never really looking at a finished image if you're watching some video shot piece - you're looking at two different fields at once.  You may think "wait - if movies are 24 fps... how do they play back on TV?"  Well, they repeat frames... but they don't just repeat frames in full they use something a Pull Up to add fields so it's a little smoother.The problem is that interlacing looks terrible on the web and it looks terrible on most new technology and the majority of people who should even know better seem to mess up footage that has interlacing as it goes to other mediums.  I cannot tell you how much footage we get from studios and places that really should know better than have converted their footage in such away that it is impossible to reverse engineer it even back to something clean.  If something is NOT interlaced  it's called "Progressive."As a result, I have become a huge advocate for using 29.97 progressive for EVERYTHING (except theatrical released projects).  Anytime people argue  with me, I send them to some of my client's sites where they have productions I've shot and productions other people have shot and you can see that as usual, the interlacing was not handled right and/or it just persists and looks bad on the web.   So 29.97 progressive looks good on the web, it looks good on US TV and Video.  You can pull still frames from it which look nicer.  Shutter Speed:  Before digital there was a disk that would spin around and expose your film half the time and block the film the other half.  It would SHUT OUT the light... Shutter... or like shutters o the window.  What this affects is motion blur.  The longer something is exposed, the more blur there will be.  We're used to watching 180 degree shutter which in the digital world is the equivalent to TWICE your frame rate.  So to keep things simple, just set it to twice your frame rate.  If you set it to less than that you get a more staccato type effect (think Gladiator fight scenes) - if you set it to more you ought to get a slurring effect.   So - this is the last thing that is affecting your light in take.... so let's review:Basically - set your frame rate to 29.97 progressive for anything but theatrically projected on film or , set your shutter to twice your frame rate, set your ASA to something like 320 if you have enough light - maybe 200 if you have too much light or up to 500 or 640 if you don't have enough light, after that just shift your f-stop until the picture is what you want.(Cinematographers are probably cringing at my simplification here, but this is really just meant to help people trying to start.)Next up, zoom vs. prime and then after that maybe a little about lighting.

about 11 years ago 0 likes  3 comments  0 shares
Scottiehui 97 scottiehui
This is great info! Thanks!
about 11 years ago
45862083 0af2fd4d5d
i pray for the day that interlaced video ceases to exist. :-P
about 11 years ago

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April 13, 2007