Double edge transfer Beauty Dish

Note the neck below the chin, this is with the Elinchrom translucent deflector about 5" from the A Head bulb on the Kacey 22" BD. 22" inches from bulb to subject. I'm wondering if the smoothness of the mannequin is amplifying an effect that won't show in a real world shot.

I spent today measurbating to the max. Compared the 100cm Elinchrom DO with all permutations of diffusers and deflectors, same with the 70cm Elinchrom square with grid and the Kacey 22" BD.

DO and Kacey shot at 39"
Kacey then shot at 22"
70cm shot at 27" and 40"

HOSTED PHOTO
please log in to view hosted photos in full size.

I believe the problem is with the solid/opaque deflector. By having a solid deflector, when you slice the light down the middle, it becomes 2 separate light sources instead of just one. You don't see the pattern on a white wall because the wall is 2 dimensional and flat. But if you were to stick an object in front of that white wall... then you should start to see varying patterns of the dual-shadow (with a solid deflector), depending on the angle of the BD hitting the object.

It would be kind of like a full solar eclipse. Here's a simple diagram:
(image linked from http://www.mreclipse.c​om/Special/SEprimer.ht​ml)

Here is close crop from my real life shoot with kacey dish and speedlites:

PacAce wrote in post #11560317
...There was even a moment when I was suspecting that the shape of the flash tube had something to do with it. In other words, would you get the same shadows if you used a hotshoe flash instead of a strobe?

You certainly would! I just tried it. Same DIY BD as used in my previous post but this time I mounted it on a Cheetahstand Speed Pro bracket with a Nikon SB800 on board.

With the flash head positioned just inside the BD, this is what you get:

jwcdds wrote in post #11560521
I believe the problem is with the solid/opaque deflector. By having a solid deflector, when you slice the light down the middle, it becomes 2 separate light sources instead of just one. You don't see the pattern on a white wall because the wall is 2 dimensional and flat. But if you were to stick an object in front of that white wall... then you should start to see varying patterns of the dual-shadow (with a solid deflector), depending on the angle of the BD hitting the object.

It would be kind of like a full solar eclipse. Here's a simple diagram:
(image linked from http://www.mreclipse.c​om/Special/SEprimer.ht​m)

http://www.mreclipse.c​om/Special/image/SEDia​gram1c.JPG

The moon is your solid deflector and the sun is your massive BD + bulb.

With a translucent shield, the light from the center overpowers the reflector portion... thus hides the dual-shadow effect.

Yes!!!! Julian, you're a genius!!! That's exactly the phenomenon that's causing the double shadows. I just verified it by using an 8" reflector and a silver deflector, and then using a notebook to block of portions of the light from the reflector, making one of the two shadows disappear. Mystery solved, as far as I'm concerned.

Now, what's the official name of this phenomenon?

It's called penumbra.

http://en.wikipedia.or​g/wiki/Umbra

navydoc wrote in post #11561471
It's called penumbra.

http://en.wikipedia.or​g/wiki/Umbra

Thanks for the the very informative link, Gene. Based on that link, I think the phenomenon is called antumbra.

PacAce wrote in post #11555247
Yes, it should be interesting to see moving the deflector closer in would do.

And if you can't get the double shadows to get any better, there is the option of using a translucent deflector you could try to see if that works out better for you.

See below, left is supplied deflector at 2.5", the right is translucent at 2.5".

HOSTED PHOTO
please log in to view hosted photos in full size.

jwcdds wrote in post #11560521
I believe the problem is with the solid/opaque deflector. By having a solid deflector, when you slice the light down the middle, it becomes 2 separate light sources instead of just one. You don't see the pattern on a white wall because the wall is 2 dimensional and flat. But if you were to stick an object in front of that white wall... then you should start to see varying patterns of the dual-shadow (with a solid deflector), depending on the angle of the BD hitting the object.

It would be kind of like a full solar eclipse. Here's a simple diagram:
(image linked from http://www.mreclipse.c​om/Special/SEprimer.ht​ml)

The moon is your solid deflector and the sun is your massive BD + bulb.

With a translucent shield, the light from the center overpowers the reflector portion... thus hides the dual-shadow effect.

Thanks for the post Julian. This is what I initially suspected.

I'm curious what others experience using Mola, Speedotron, etc.

windpig wrote in post #11563256
Thanks for the post Julian. This is what I initially suspected.

I'm curious what others experience using Mola, Speedotron, etc.

I use the Mola Demi with the aluminum perforated diffuser stacked with an Opal glass diffuser. This means that there is some light coming from the central deflector, but it is less bright than the perimeter of the dish. I do get a hint of the double shadow under the chin, but it's diffused somewhat by the light coming through the center deflector.

ok, thought i'd play the game, here's some with the Mola setti

first at 20" 45 degree angle to glasses

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

just to make sure i did it right now the speedotron dish center blocked
20" at 45 degrees

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

FJ LOVE wrote in post #11565639
ok, thought i'd play the game, here's some with the Mola setti

first at 20" 45 degree angle to glasses

Hosted photo: posted by FJ LOVE in
./showthread.php?p=115​65639&i=i42040974
forum: Flash and Studio Lighting

now at 31" 45 degrees

Hosted photo: posted by FJ LOVE in
./showthread.php?p=115​65639&i=i245543554
forum: Flash and Studio Lighting

What deflector are you using on the setti?

I think he's using the same as what I do on the Demi, a perforated aluminum deflector stacked with an Opal glass diffuser. It looks like this...

Sheldon N wrote in post #11566495
I think he's using the same as what I do on the Demi, a perforated aluminum deflector stacked with an Opal glass diffuser. It looks like this...

and looks like this when shot on-axis (note some illumination coming from the center)...

Thanks

The deflectors and hardware start to add up $. I'm hoping the specs on the mounting holes are available from Mola.