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-   Hybrid Still/Movie/MP3 Digicams (https://forums.steves-digicams.com/hybrid-still-movie-mp3-digicams-85/)
-   -   Comparing "low light" (https://forums.steves-digicams.com/hybrid-still-movie-mp3-digicams-85/comparing-quot%3Blow-light-quot%3B-110654/)

brachiopod Jan 2, 2007 11:23 AM

People keep asking about "low light" with the hybids. In order to really compare light levels for different conditions, people should use a light meter to read the scene that they are talking about so that we can compare light levels. You say you don't have one? Yes you do, it is your camera. If you take a still picture at ISO 100 and look at the f stop and shutter speed used, then you can determine the light level (at least for what your camera considers a good exposure). To compare, you should convert your aperture and time value to "exposure value" or "EV". Each "EV" is a factor of two in light. The higher the number, the more light there is. Yes, EV can be negative for very little light.

Use the forumula:

EV=log(f*f/t)/log(2)

where "f" is your aperture (for example if the aperture is f/4 you would use "4.0" and t is the exposure time in seconds (so for 1/60 second you would use 0.0166. Log(2) is 0.301

So now if someone takes a sample film "under some streetlights" but says that it was EV 4, you can compare your lighting conditions to theirs if they tell you their EV value.

The only things to watch out for is 1) It has to be ISO 100 for your still shot, set your camera to ISO 100. 2) Some cameras start to goof up the exposure on really long shots (several seconds) and may not give a correct reading. 3) meter the lit area generally.











fishycomics Jan 2, 2007 12:06 PM

bran............

X-ollent point, and taken



I just use the histogram.

http://media.putfile.com/histogram

It tells me i got light and good to go. but i was too fast to reply it does not work onvideo, but yes it can tell you is it bright enough


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