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View Full Version : Varying Brightness in my vidoes--normal?


Walter Laich
11-15-2005, 01:50 AM
I finally got my CVS and plane together and in the air. Was flying at 4:30 pm so sky wasn't as bright as it could have been. Flight at 5:30 with sun down below the horizon was either OK in sky and pretty much black at the ground until the camera had been pointing at it for a few seconds. Then got something that looked OK, not great but OK.

Thinking that the light needs to be overhead (12 Noon style) so everything on ground is well lit--know still going to have changes from sky to ground but I figure that's normal.

thanks
w

weller
11-15-2005, 05:37 PM
Walter, I'm not quite sure I understand what your doing but I think you are asking why your video shows inconsistant lighting as your plane flys around. My background has been as a photographer.

The problem stems from the camera being set on automatic exposure. You may or may not have control over automatic and manual exposure with the camera you're using. With automatic video or movie cameras the meter is always attempting to correct the exposure. This results in delayed exposure changes and yields unatural viewing results. We as animals aren't even aware of changes in light levels because our brains respond so quickly.

Professionals take light readings when shooting video or film and set the exposure manually for what the primary lighting condition will be. Then if the camera points into the sun briefly the image is over exposed but natural in appearance...the whole visual effect is more natural. In automatic mode the camera tries to correct for the bright sun by closing the lens down. This is attempt at correction is disconcerting to look at when viewing. The more expensive equipment is faster at exposure changes, which helps some but is not the best answer.

What do you do if you cannot manually set the exposure? Plan your photography on a slightly overcast day when the light is even in all directions or shoot when the sun is pretty much over head as you suggested. Good Luck!

ke4fmk
11-15-2005, 05:52 PM
Great answer Weller.

ForestCam
11-15-2005, 05:57 PM
I've seen some video shot from a CVS camera and the weird thing was when the camera pointed directly at the sun for a second it made the sun a black dot, almost like an eclipse.