Paul C. Buff, Inc. Technical Forum

I ordered one recently and slapped it on my B400. from a head on shot i am seeing a ring of light about 18" out from the center with fall off in each direction across the fabric. This is also resulting in a ring of light with a dead spot in the middle at a distance of 15'. I'm using the speedring mount and have everything firmly mounted.

Should the fabric have a different tension across its surface when opened? should i adjust the "upper" section of the PLM to try and focus it differently? It doesnt feel to be anywhere near as difficult to open as either of my 51" White PLMs do if thats a way to compare...

You may find you will need to focus the light at different distances. This is done by loosening the knob inside the PLM and letting the umbrella dome slide up or down the position shaft. You can then retighten the knob, letting it friction hold on the shaft.

The 86" PLM will not have as much opening resistance as your 51".

The flashtube must be approximately parallel to the face for the PLM fabric to focus properly. For close in lighting (less than 8-10'), place the flashtube about 2" in front of the front perimeter. 18" destroys the whole beam. Otherwise you will get the dead spot in the pattern center.