F Stops

Started Aug 11, 2012 | Discussions thread
dosdan
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Re: Acute.
In reply to Great Bustard, Aug 14, 2012

Great Bustard wrote:

Question: for the same scene, do f/2.8 1/100 ISO 100 and f/2.8 1/100 ISO 1600 have the same exposure?

Yes or no, please.

Question: What role did the ISO setting play in the scenario above?

Open ended response welcomed.

Since ISO has nothing to do with the exposure, and assuming the same scene luminance, then the same f-number & shutter speed causes the same number of photons to be captured per unit sensor area, and if they are the same sized sensor, the same number of photons.

The higher ISO (or turning up the so-called "exposure" gain afterwards in a raw converter) will make the 2nd image appear brighter (and noisier since the shot noise has also been boosted). So the ISO setting is affecting the rendering of the captured image.

Dan.

Dan.

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