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June 15th, 2005, 05:06 PM | #1 |
Inner Circle
Join Date: Jun 2005
Location: Saskatchewan
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Filming flight
Good afternoon,
I am new to the forum. I have been involved with photography for 40 years. I did my first films on a bolex B-8. I purchased a gl2 in april. The learning curve has been steep. I have one issue that I am having trouble with. I shoot primarily wildlife. I film falcons flying and The wing strokes are flickered, lack of a correct term. When I move them to slow motion on the editor there is no flicker. With falcons I film want them in normal wing beat speed and then the stoop I move into slow mo. I was curious if any of you know what causes that. I move to TV with shutter priority and crank up the shutter speed to 1/8000. at 1/15000 you start getting to much grain. Any casual suggestions out there? also, in outdoor lower light conditions what do you do to reduce grain in pictures? Dale Guthormsen |
June 15th, 2005, 09:34 PM | #2 |
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Location: Baton Rouge, LA
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Dale,
I always shoot in frame mode, thus reducing the flicker of fast moving objects when in interlaced mode. I also always shoot in manual exposure so that I can control gain (always 0) and thus control the "grain". (There may be a way to do this in TV mode...). Of course, with the gain at 0, then you'll have to adjust the shutter lower when the light drops... Although you will get wing blur at lower shutter speeds, I think you'll find the blur in frame mode is not totally objectionable. I like the color and images I get from my GL2. Keeping the gain at 0 really helps.
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Michael A Westphal |
June 15th, 2005, 10:16 PM | #3 |
Retired DV Info Net Almunus
Join Date: Dec 2001
Location: Chicago, IL
Posts: 6,943
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Welcome Dale,
I am not a wildlife shooter, per se, but believe that I can add to Michaels remarks to add clarity. As in still photography there are 3 basic variables controlling exposure in videography, although not the same 3 and not with the same effects. Lens aperture (in f-stops) is the same. Gain adjusts the sensitivity of the CCD to light. Somewhat analogously to high ISO film, increasing gain will also increase grain in your footage. Generally, it's an adjustment of last resort. Shutter speed is the wild hair, as video cameras do not have true shutters (unlike film cameras and still cameras). Basically, shutter speed controls the sampling rate at which the camera reads the CCD. The effect I believe you've described sounds like strobing which would be expected with higher shutter speeds. For a standard NTSC video camera such as the GL2 the "natural" shutter speed is 1/60 sec. Once you get above 1/100 or so you risk getting some strobing in fast moving subjects (such as wings). There is much more to the story, of course. But basically you might do best for your falcon work by managing your exposure manually (rather than using any of the program modes) and forgetting that you have a shutter speed higher than 1/00, leaving it normally set for 1/60. Use the camera's built-in ND filter to further control exposure in bright situations, perhaps adding an external ND filter when needed. Have fun!
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Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com |
June 16th, 2005, 09:51 AM | #4 |
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Join Date: Jan 2005
Location: mafra portugal
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maybe it's nle's fault?
this just stroke my mind when reading your problem:
when you watch your footage on a computer before encoding it to a lower bitrate format (dvd) sometimes the cpu power is not enough to deinterlace it to the progressive format of the monitor. it happened a lot to me before i started to preview everything through dv-out into a tv set. maybe it's as simple as this or most probably completely out. :) just my .02€ edit: just to explain my point of view...dv is compressed...the more motion the more problems for the cpu to handle...if there is no flickering in slowmotion that might be it. btw...dont preview your dv avi's with media player...there's something ith it that makes them always "flicker", maybe wrong use of codecs...seen it happen in different computers |
June 16th, 2005, 07:23 PM | #5 |
Inner Circle
Join Date: Jun 2005
Location: Saskatchewan
Posts: 3,048
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filming flight.
thank you all for the input. I will get out this weekend and run some tests.
As for the editor, the same visual can be seen on the big screen. How ironic, I went for a camera for more shutter speed and that may be my problem!! I will run tests this weekend and film some waterfowl. I have learned more sense I found this list than the last year and a half shooting video!! the best always, dale guthormsen |
June 16th, 2005, 09:29 PM | #6 |
Retired DV Info Net Almunus
Join Date: Dec 2001
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Dale,
A very good way to experiment with shutter speeds and exposures is to set up your camera on a tripod near a busy road. Shoot various clips at various shutter speeds, and be sure to slate each clip so that you can easily identify and evaluate them during playback.
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Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com |
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