Paul C. Buff, Inc. Technical Forum

I am just getting started with two soft silver PLM umbrellas with 8mm umbrella style mounts and 7UR reflectors, mounted on Einsteins, and would like to know how to position them.

I am using them in a following setup to take portraits, indoors at home:

A. 64 inch PLM with a white diffusion fabric as a FILL behind the camera position at about f/4
B. 51 inch PLM as the KEY light, towards the right of the camera at 30-45 degree angle a foot above the target, at about f/11

I get it that depending on where the shaft is in relation to the Einstein varies the spread of the light. But is there a spot where focus is the sharpest (i.e how far should the shaft protrude from the back of Einstein for smallest bright spot)? I tried putting B in front of a white background, lowered f stops until I could see the light variations, but I could not tell where the shaft should be for the sharpest focus. True it does not have to be positioned perfectly there, but it would serve as a starting point to make adjustments.

In a situation like above, would not using the diffusion fabric in B give a better light fall off over the target?

To get a light fall off on the portrait, is it a good practice to rotate the PLM toward the camera so that the side of the PLM away from the camera is where the light on the object is shining from ?

Any input will be much appreciated.
Thank you.

The Open face of the 7UR should just meet the open face of the PLM or just inside.

The soft silver will not show a large difference with minor variations from this position, but this is a starting point.

Soft Silver PLMs have a wide tolerance to lamp position, so focusing isn't critical. Super Silver PLMs are critical in this area, and should generally be used with the flashtube parallel to the open front of the spokes.

The focal point changes slightly with distance to subject. If ambient light is low enough and modeling lamps are on, I usually adjust by moving the PLM in and out and using the position that projects the best beam. If 10' or less, this usually occurs with the face of the PLM 2 or 3 inches back from the flashtube/modeling lamp.

Thank you so much for taking the time to respond, Paul. This is very helpful.

Thanks. Seems I was not positioned correctly.