baffle for diffusion panel

[rudy_tolentino]

to avoid hotspot using softbox an internal baffle is added (cloth

panel placed between face panel and the light source).

 

my question is, in a diffusion panel, is there a need for baffle to

avoid hotspot. if so is there an impirical formula or rule of thumb

to follow to determine the distance between the front panel and the

baffle and the distance between the the baffle and the light source.

 

info on this subject is highly appreciated.

[mike_lepp1]

A light placed behind a diffusion panel will have a hot spot. The size of the hot spot and apparent size of the light on the subject will be determined by the distance the light is placed behind the diffusion panel. The further the light is behind the diffusion panel, the softer/larger overall light source will be.

 

To make the light source even softer/larger, you can add a modifier such as a brolly, umbrella, softbox, wide angle reflector, etc, to the light.

 

As far as rules, I think it boils down to what your desired intended outcome is. For instance, I've intentionally used the hot spot to my advantage.

 

I hope this helps.

[tom_musselman]

Rudy, a diffusion panel is a light baffle. Just like in a softbox, if you stack two diffusion panels there will be less hotspot and more diffusion. I have found that a one-stop diffusion panel has a brighter hotspot, and less diffusion, than a two-stop diffusion panel. Good luck!

[er1]

Some studio lighting units are a fixed distance to the baffel and some are adjustable. As Mike stated, the hot spot can be used to your advantage. I've never had a problem with this issue. Or you can consider a light modifier panel. This will offer you the opportunity to easily adjust the lighting distance to the diffusion panel.