Re: 18% grey
Re: 18% grey
- Subject: Re: 18% grey
- From: Robin Myers <email@hidden>
- Date: Mon, 11 Apr 2005 05:48:25 -0700
On 10 Apr 2005, at 15:34, eugene appert wrote:
<x-tad-bigger>Obviously the camera’s dynamic range is greater than the target but I am perplexed by the fact that the same meter and grey card produce perfectly exposed Ektachrome from the same target. Is there any way of explaining why an exposure taken from a meter-reading of a Kodak 18% grey card produces a perfect slide of the Q14 target, yet and at the same time produces an underexposed digital file that was exposed according to the premise that 18% grey = L*54 in an 2.2 space?</x-tad-bigger>
Digital cameras typically overexpose the image by 2/3 to 1 f/stop. This is done purposely to increase the observable shadow detail at the expense of burning out the highlights. The bad news is that light colors such as yellows, some magentas, and so on (such as you might get in flowers), are turned into burned out whites. Try setting your camera for a 2/3 stop underexposure. If that is not enough, then try a 1 stop underexposure.
<x-tad-bigger>My results may very well be the product of some oversight or particularity but, it appears as though digital capture requires a darker grey card.</x-tad-bigger>
If you use a darker card then the sensor's signal-to-noise ratio becomes low, meaning that there will be a significant amount of noise in the image so you will be setting the exposure based more on noise than the actual image. I suggest underexposing and using a lighter card for setting the neutral balance.
Robin Myers
email@hidden
www.rmimaging.com (home of the Digital Gray Card(tm))
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| | >Re: 18% grey (From: "eugene appert" <email@hidden>) |