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Lighting and Zoom


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#1 k3shooter

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Posted 07 July 2005 - 06:52 PM

Can someone please tell me if additional light meter/ stop adjustments are required for a zoomed in shot of my subject. Is there a rule of thumb that suggests how much to compensate for light regarding camera distance from subject and a zoomed in focal length. Or, put another way when I take a light reading and obtain a f stop from the meter, does this reading/fstop suffice for the entire range of the zoom regardless of camera position relative to the subject. Sorry, if this is a bone head question or too technical or confusing, just trying to wrap my brain around this. Thanks.

Regards,

Greg
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#2 David Mullen ASC

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Posted 07 July 2005 - 07:01 PM

The focal length of the prime or zoom does not affect the exposure you set (i.e. you don't compensate for the focal length, so if you switch from 25mm to 100mm, let's say, you don't adjust the exposure unless for creative reasons).

A few very long zooms drop off in exposure just at the extreme telephoto end, which you can see -- but most of these are on video cameras and you probably wouldn't be using a light meter to set the exposure on a video camera anyway.

You will find though that many telephoto and zoom lenses don't open up as much as a prime, so if you had lit a scene to an f/2.8 and then put on a zoom that only opened to f/4.0, or a telephoto that only opened up to f/5.6, you'd have to adjust the light level. So when lighting a scene, thinking about the speeds of all the lenses you plan on using.
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#3 k3shooter

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Posted 07 July 2005 - 11:46 PM

ahhhhhh.....David, Thank You. Now I can sleep tonight! Thanks for being so clear, concise and quick (response time). Makes sense.


Greg
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#4 Chris Keth

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Posted 11 July 2005 - 11:17 PM

ahhhhhh.....David, Thank You.  Now I can sleep tonight!  Thanks for being so clear, concise and quick (response time).  Makes sense.
Greg

<{POST_SNAPBACK}>



That's David :-D I haven't been back here in a while and I forgot how much I like reading through threads and David's (as well as everyone else's, of course :P) replies. I have learned a lot from this forum.
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Ritter Battery

Visual Products

Metropolis Post

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rebotnix Technologies

Media Blackout - Custom Cables and AKS