Paul C. Buff, Inc. Technical Forum

Is there a way to extend the flashtube past the ringmount so that there is a more even spread of the light inside a softbox/BD, etc?

I've noticed that the flashtube sits so deep in the ringmount that the light gets redirected forward. This makes a brighter hotspot on the diffuser, thus the need for an internal baffle.
If there was some kind of spacer (like that offered by Quantum for their flashtubes when used with the wider reflector) to extend the flashtube past the ringmount, the light would have a more even spread of light to the sides and back of the softbox like that of the older Profotos (not D1's). It would be nice if the spacer was glass-covered to protect the tube from fingerprints and damage from mounting the softboxes. I've had one tube explode on me because I accidentally touched it when mounting a softbox.

We do not have a way to extend the flash tube away from the body of the light. With our light design, the tube already breaks the plane of the rear of our beauty dish. With our softbox, the light does a fine job of reaching the rear most areas of the interior. There will be a hotspot in the middle of the fabric, regardless of tube position, since a) some rays will travel straight through the fabric, and that is where that will happen, and b) the tube is closest to the center of the fabric than it is to the edges. Extending it toward the fabric will only exacerbate this.

Having an inner diffuser will scatter the light, thus reducing or eliminating the direct rays.

Actually, I've found that moving the flashtube (of my Einsteins) forward into a softbox using a flat speed ring insert does significantly lessen the central hotspot:



The remaining hotspot can be further ameliorated by using the octa's inner baffle. I attribute the improved evenness of illumination not to the repositioning of the flashtube as much as to elimination of the forward bias caused by the conventional polished, dished AB insert. In the above comparison image, a Kacey AB adapter was used which is perfectly flat.

Dave F.

Thanks for the reply tetrode.

I've always known this to be the case and your pictures are proof. It seems that some people are too established in their ways to listen to the suggestions from users out in the field. Yes the flat ring from Kacey is definitely a better design to allow more even light spread. I just wish there was some protective glass around the flashtube like Norman flashtubes that will serve both as protection and advance the tube past the ringmount. Either way would be better than what is available now.

Do you have the equivalent photos with the inner diffuser installed? Since that is how most of us tend to use it, seeing how significant the difference is in the actual usage configuration would be very interesting.