Flash diffuser question

[axle01]

Hey guys and gals I’m making a couple of flash diffusers and using 3mm frosted perspex, question is should I position the frosted side or the shiny side towards the flash.

Al

[ameerat42]

At first fought thought I would have said the matte side, as the shiny side would be sure to
reflect light more light. But because the shiny side will still reflect some light internally...
- You had better try it out and tell us the results.:nod:

[axle01]

At first fought thought I would have said the matte side, as the shiny side would be sure to
reflect light more light. But because the shiny side will still reflect some light internally...
- You had better try it out and tell us the results.:nod:
Damm I was hoping you would know, your standing with me has just taken a nose dive..........:lol:

Al

[bobt]

Damm I was hoping you would know, your standing with me has just taken a nose dive..........:lol: Al

Yeah ... quite disappointing really ..... you think a guy knows everything and then ........

My thoughts would be that you *don't* want the shiny side facing the flash because it would reflect the light back at the flash rather than towards the subject! Of course I could be wrong .....

[axle01]

Yeah ... quite disappointing really ..... you think a guy knows everything and then ........

My thoughts would be that you *don't* want the shiny side facing the flash because it would reflect the light back at the flash rather than towards the subject! Of course I could be wrong .....
Mate seriously you have a 50/50 chance of getting it right.

I have made it so I can mount it either way so trial and error.

Al

[ameerat42]

We eagerly await your results. - I speak on behalf of Bob as well :nod:

I'd be interested in your test method. You'd have to make the conditions
vary only in the orientation of the diffuser sheet.

[nardes]

I suspect that if you place the frosty side towards the flash head, then any light reflected back to the flash head would be somewhat randomly scattered due to the varying angles of the reflecting surface of the diffuser material.

If you put the shiny side to the flash head, then I reckon any light reflected back would tend to have a more consistently fixed pattern, as the reflecting surface is more even. I'm not sure what % will be lost in reflection vs what passes through the diffuser.

What is interesting is that when I look at my Canon EX 600 Speedlite, the outer (subject-facing) flash head is smooth in the centre and ribbed towards the edges, with a sort of Fresnel Ring pattern, maybe to focus the beam towards the edges rather than let it randomly scatter.

Cheers

Dennis

[axle01]

Thanks Dennis and AM I’ll do some tests and advise of the results,,,,,,stay tuned.

Al

[axle01]

Well that was a anticlimax I made the mount to hold the 400 x 400 Perspex, mounted it on the flash tripod, set up the flash unit, peeled off the paper backing and bu*ger me it’s frosted both sides.

Al

[bobt]

Well that was a anticlimax I made the mount to hold the 400 x 400 Perspex, mounted it on the flash tripod, set up the flash unit, peeled off the paper backing and bu*ger me it’s frosted both sides.

Al

That is so funny ..... thanks for making my Sunday. :lol:

[ameerat42]

So the question now becomes just: Which side should face the flash? :p:p:p

[bobt]

So the question now becomes just: Which side should face the flash? :p:p:p

That's easy .... the other side. :nod:

[axle01]

I don’t bat for the other side but I’m not giving up I’ll try both sides.

Al