[Radiance-general] lighting fixtures data

[Gregory J. Ward]

Hi WIll,

Funny you should mention this, because here I find myself attending  
Rob Shakespeare's "Virtual Scenography in Live Performance" symposium  
at Indiana University <http://www.indiana.edu/~vslp/>, where a bunch  
of theater types and researchers are gathered talking about lighting,  
simulation, and the like.

I will definitely ask Rob if he has any data, and maybe he'll respond  
with some pointers as well.  Are you planning to input this directly  
into Radiance, or do you have other tools in mind as well?  (I.e., do  
you need IES format data, or can you get by with something not easily  
converted to IES?)

The reason I ask is that I've been toying with HDR imaging as a quick  
and convenient method to get at certain types of photometry, where  
the projection angle is small but the pattern potentially complex --  
i.e., theater lighting instruments.  The method is simple, but there  
are a few details to work out.  Basically, you set your instrument  
and point it at a blank wall or ceiling or some diffuse, white  
surface large enough to encompass the beam.  Then, you take an HDR  
photograph of the beam pattern.  The part I haven't worked out  
completely is using this as input to Radiance, but if you have some  
basic distance and beam size measurements, this should be  
straightforward.

You would of course need a reasonable digital camera -- SLRs are  
generally better due to the better flare characteristics of their  
lenses, and access to the light instrument of interest and a dark  
room to do the measurements.  If this is of interest, I would be  
happy to help you assemble an example photometric distribution as a  
proof of concept.

-Greg

> From: william reynolds <william.reynolds at oriel.ox.ac.uk>
> Date: March 3, 2006 6:55:37 AM EST
>
> Hi there
>
> I've been trawling the internet for a while now looking for ies  
> data files (or any other standard fot that matter) for theatrical  
> lighting instruments, with out any luck at all.
>
> I've found lots of data architecturial lanterns, and lots for the  
> actual bulbs (from ge, osram etc)but these aren't very useful when  
> you're trying to light a theatre, with the lanterns that are  
> available there.
>
> The only best photometric data i've found is from ETC:
>
> http://www.etcconnect.com/docs_downloads/datashts/S4_19_Deg_vD.pdf
>
> where they give you a "Candlepower Distribution Curve" as well as  
> field and beam angles, but most places dont even give that.
>
> I also have the problem that most of the lanterns i'm interested in  
> are focusable, and many are zoomable as well, so i need data at a  
> couple of focus/zoom settings (i can then interpolate between these).
>
> Does anyone have any ies (or other useful format, or even radiance  
> format) files about any theatrical lanterns? ideally i'm after  
> selecon lanterns, but i would be happy with some generic data for  
> the standard lantern types:
> -profiles (of various angles)
> -fresnels
> -pc's (less important)
> prerferably data at a couple of focus settings, and data for 1kW  
> and 500W lanterns.
>
> I dont have access to the facilities to make my own measurements,  
> and i can't figure out how to use the data provided (http:// 
> www.seleconlight.com/english/support/english/acclaim%20fresnel.pdf  
> for the selcon fresnel i'm particulary interested in) to estimate  
> the figures.
>
> So if anyone can come up with any advice, or has any suggestions of  
> where I can get hold of this data it would be very much appreciated.
> [I will be using the data in part of an undergraduate engineerig  
> degree project, and wont use anythign for any commercial purposes  
> if it makes any difference to anyone].
>
> Thanks for your help everyone
> will