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A way to determine actual settings vs. reported settings

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Offline cybercom

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A way to determine actual settings vs. reported settings
« on: 12 / May / 2008, 10:32:15 »
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There seem to be numerous discussions regarding reported EXIF data that is not reliable: ISO's of 1, Av's of 2.8 and Tv's in the tens of thousands.

Using the histogram for benchmarking will help clarify these matters.

While a full discussion of the Zone System, 18% reflectance and histograms is available from numerous other sources, the relevant concept is that the histogram can be used to provide points of reference from which more accurate conclusions can be drawn.
 
One simple example: ISO bracketing in continuous mode with increasing exposures will show the histogram incrementing with each consecutive exposure, even though the EXIF data remains the same for two or three exposures. Through interpolation, more accurate ISO values can be determined for the intermediate exposures. 

HTH,
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Offline PhyrePhoX

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Re: A way to determine actual settings vs. reported settings
« Reply #1 on: 29 / May / 2008, 18:25:38 »
hi, seems very interesting, can you maybe provide some sample histograms or pictures so people like me can understand better? this maybe should be added in the wiki or something, so future benchmarks are more accurate.
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Offline cybercom

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Re: A way to determine actual settings vs. reported settings
« Reply #2 on: 29 / May / 2008, 22:56:25 »
I'll be glad to go into further detail once I return to civilization (hi-speed internet service). Right now I'm on 26kb dialup...!  :-(
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Offline Psychokitty

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Re: A way to determine actual settings vs. reported settings
« Reply #3 on: 02 / June / 2008, 17:37:26 »
Quote from: cybercom on 29 / May / 2008, 22:56:25
I'll be glad to go into further detail once I return to civilization (hi-speed internet service). Right now I'm on 26kb dialup...!  :-(
...And on that note, here's my 12MP stereoscopic aerial shot of the Andes in it's entirety for all to enjoy:

...

...

...  :P
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http://chdk.wikia.com/wiki/DoF_Stacking
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Offline cybercom

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Re: A way to determine actual settings vs. reported settings
« Reply #4 on: 04 / June / 2008, 14:07:00 »
Before I get started, I'd recommend this article as background on Histograms in general:

Understanding Histograms

and this article on the Zone System and how it relates to 18% reflectance, middle grey:

Zone System

These concepts will be critical to understanding what you are seeing, what your camera is doing and how these tools can be used for measurement.
 8)
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