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07/06/2004 12:33:13 AM · #1 |
Can anyone tell me about video hardware? I'm looking specifically for info on how one measures video lenses, how they change aperture? What's the deal with that? It seems that video lenses can't have to be tweaked as carefully as photo lenses, with respect to aperture settings.
Do video lenses have continuous apertures? Or f-stops?
Are they measured in mm? Do you have a video lens that's a 70-200mm for example?
If you use a really small aperture for a huge DOF, do you have to sorry about there not being enough light for 30 frames per second?
Basically, I want to hear from someone who knows about video lenses. Can someone lay out the basics in photography geek terms?
Thanks in advance!
-Will |
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07/06/2004 12:42:37 AM · #2 |
EddyG posted a cool link before showing people using a 1200mm canon lens on a canon video camera. I guess they are interchangable.. but I have also heard the reason that the still photo quality that comes from video cameras is so poor, is simply because of the lens.
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07/06/2004 12:54:46 AM · #3 |
Video cameras (at least in VHS format) are capturing a 640x480 pixel image (probably higher now with hi-def, but not in the multi-megapixel range). I don't know how they handle it for consumer-type video cameras -- I know some of those go up to a 2MP image, but I haven't noticed them going much over that.
A friend of mine who works in video recommended the Canon GL(?) semi-pro camera -- about $1400 now -- which has outstanding image quality for video. |
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07/06/2004 03:48:35 AM · #4 |
i have only worked with the canon series of DV cams--namely the GL-1 and the XL-1. the XL-1 is awesome, but the GL-1 is a certainly a great camera. if i were to get a basic video camera, that would be the one. i don't like using video cams for stills however. for one you have to de-interlace your image in order to get the final image or full frame effect from the 2 fields, or half pictures that your camera captured. so this will certainly affect your final image quality. not to mention the interesting effect of the aspect ratio difference, since standard ntsc (US) captures 720x480 (visual) tv standard pixels/scanlines--the rectangular pixels of your initial imported image against the square pixels of your monitor--basically makes your subject's head look rather like an egg. :) but these are small things that can be fixed, and you can always resample an image up in resolution if you really wanted to make a print of it, but the quality is still not that great.
as far as lenses go--it has been a awhile, (and with technology moving as fast as it does, it may be different now) but the XL 1 was the only one that i worked with that had interchangable lenses. |
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07/06/2004 07:47:08 AM · #5 |
I guess I'm more looking for some optics info on the kind of cameras they used to make feature films. I've seen those shots where they create dramatic effect by changing focus from something in the background to something in the foreground. I assume they have a focus ring somewhere they are turning. But to accomplish that, they use a very shallow DOF. How do they select that? F-stops? And do video cameras use the same measurement system for zoom lenses?
I understand pretty well the details of the output formats, the aspect ratios, HD resolution, etc. It is interesting to note (as people are here) that still cameras blow away even the best video cameras for sheer pixel resolution. We've still got an edge there. :)
Anyone else have a background in video that should shed some light for me, before I start Googling like mad?
-Will |
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07/06/2004 10:29:48 AM · #6 |
ok, i think i am following you. in answer to your dof question, you are talking about rack or pull focusing. that is one of the simplest things to do with video, since the easiest way to focus a shot in video is by zooming all the way into your subject and manually setting the focus. very simple and pretty cool effect. and yes, it is measured in f-stops--usually around f1.6 to f22, maybe that depends on the camera, not sure. you can then adjust the exposure automatically or manually, as most of these cameras have programmed AE with shutter and aperature priority settings.
any of these prosumer 3 CCD cameras are comparable in features, and any one could be used to shoot a film. i remember when spike lee broke ground by filming bamboozled almost entirely on a sony video camera (comparable to the XL-1). now everyone is doing it. :)
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