[Radiance-general] dynamic range

[Despina Michael]

Thanks Axel,
your ansewer was very explanotory and the webHDR webpage as well.

I have another question on this - how we compute Dynamic Range?
If for example: the brightest pixel has luminance 50 000 cd/m^2 and the 
darkest one 5 cd/m^2
is dynamic range 50 000/5 = 10 000:1? is that correct?
(i.e. 4 OoM)

And something more... is there any standard threshold, that "seperates" 
dynamic range to High and Low?

Thanks again,
Despina


----- Original Message ----- 
From: "Axel Jacobs" <a.jacobs at londonmet.ac.uk>
To: "Radiance general discussion" <radiance-general at radiance-online.org>
Sent: Tuesday, March 29, 2005 5:57 PM
Subject: Re: [Radiance-general] dynamic range


> Despina,
>
>> a) does dynamic range 1000:1 same as 1 order of magnitude?
> 1 OoM is like shifting the decimal point to the left/right by one digit
> (divide/multiply by 10), so 1000:1 = 3 OoM
>
>> b) what is maximum dynamic range that can exist in real world?
> Very much depends on your scene: The sun has a luminance of 10^9 cd/m2,
> and 'no light at all' would be 0 cd/m2.
>
>> c) what dynamic range can human eye see?
> Please see WebHDR:
> http://luminance.londonmet.ac.uk/webhdr/
>
>> d) what do we mean with cd/(m^2) ? where m^2: m=base, 2 = exponent
> candela per meter square is the unit of luminance. 2 is not an exponent,
> just a simple square.
> See SynthLight, chapter one for more info on photometric units:
> http://www.learn.londonmet.ac.uk/packages/synthlight/handbook/index.html
>
> Axel
>
>
>
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