[Radiance-general] Update on image based lighting

[Rob Guglielmetti]

Santiago Torres wrote:
> Hi all,
> As promised, I am posting the last results I got with image based lighting,
> especially about illuminance values under a mapped sky. 

Hi Santiago,

Thanks for taking the time to write that up.  I need more coffee this 
morning before I fully digest all the numbers there, but one statement 
at the end bears comment:

"One thing to consider is that the camera has a built-in bracketing 
option that can take up to 5 images, with up to 1 stop increments. If 
the scene has high contrast, this can be insufficient to capture the 
whole range, so manual set up might be needed."

I'm actually looking to buy a new camera for the office so that we can 
use HDR photography for survey work, mostly lower contrast stuff.  But 
I'm wondering, what is the contrast threshold where you would need to go 
manual?  I'm looking at the Canon digital rebel, which only does the 
three shot autobracket but can separate each exposure by two stops. 
Greg Ward & I discussed this off-list and he said that that is 
sufficient for what I'm looking to do.  But I assume you're talking 
about much higher contrast scenes, such as landscapes with direct sun, 
that would require a manual exposure?

----

      Rob Guglielmetti

e. rpg@rumblestrip.org
w. www.rumblestrip.org