Paul C. Buff, Inc. Technical Forum

Hello PCB,

I’m considering purchasing a PLM soft silver and have some questions. My main use will be for portraits. A noted photo author favors the standard soft box over umbrellas because he says a soft box focuses the light better (more efficient) and allows for the use of fabric grids while an umbrella “wastes” light by being less focused and spreads it all over. What are your thoughts? Which would be better for portraits?

There is a lot of truth to that and some true-enough-in-practice points. A soft box with or without grids will choke light down, and redirect it as compared to a bare bulb. Using the term focus is stretching the definition, IMO, but the idea is there.

To compare this to "an umbrella" is a bit broad. Comparing to a shoot through or white bounce umbrella, this would be quite true, as you cannot focus a diffuse reflection, like white. Comparing to a silver umbrella, properly used, the umbrella very well could be more focused and efficient.

Certainly, an Extreme Silver or Soft Silver PLM will be more focused than a softbox, as it is specifically designed to (really) focus light. This would allow for soft shadow transitions and wrapping light, while maintaining specularity and light intensity.

Add a diffusion fabric, you are looking to about the same spread as a softbox, or white umbrella.

Two more questions please.
1. I have AB800s and am looking for a quick and easy way to mount the PLM. The speedring mount option seems a little complex and time consuming -thumb screws, washers and wing nuts can get lost. If I order the Soft Silver PLM™ with On-Axis Speedring Mount (Convertible to 7mm Umbrella Mount), how would I configure it to use as a regular umbrella mount? Just slip the PLM’s 7mm umbrella shaft pole extension through the umbrella hole in the AB800 and tighten with the umbrella screw? How would this be different from ordering the Soft Silver PLM™ with 8mm Umbrella Style Mount? I guess I’m confused about the 7mm vs 8mm options.

2. If shooting portraits of older folks,would the white fabric PLM be better than the soft silver at minimizing facial wrinkles, lines, etc? I figure with the white PLM, I’d be able to use the PLM™ Black Front Spill Kill Fabric for the Japanese Lantern effect and move it very close to the subject for a very soft, wrinkle-killing effect.

Your expertise will be of great help to me.

There are a couple of options. First, there is nothing that requires the speedring, washers and wingbolt to be removed from the position shaft. Only that the position shaft be removed from the PLM. Second. You can semi permanently attach the 7mm rod and position shaft, but you will need to replace the top set screw with a longer screw to hold everything. The set screw included is not really designed for that task, and if tightened improperly will disassemble the PLM. If you do not want to assemble and disassemble, then go with the 8mm shaft variant. It will affect light no differently than the 7mm shaft.




This will be a by product of the size of PLM you use and how close you use it, and the direction in which it is aimed. Yes, you can get a shoot through very close, however, Paul was clever in the design of the PLM so that when properly attached, the 8mm shaft PLM does not protrude from the back very far, unlike many of the copy cat parabolics. The speedring version can be used with no rear protrusion. This was done to allow close proximity to the subject. The two larger PLMs should allow you to get sufficiently close. Also, texture comes from shadows, and shadows come from directional light (larger light sources offering more directions of light). Moving the light closer to the lens axis will help diminish the shadows (but also the dimension of the image).