Softbox/Diffuser types

Question

Prompted by stacking diffusers to further soften the light? I'm aware of the 'bigger is softer' rule for soft boxes & already own a couple of very simple reverse-mounted speedlight umbrellas with white diffuser fronts; vertical 60x90cm, similar to this...

Cheap & cheerful, they seem to do the job.

I'm thinking of going up to 120cm octagonals, but just wondered about two aspects before I do.
I can get the simplest octagon umbrella with white diffuser for £15, add a honeycomb for another 15, or go all out and for 100 I can get deep parabolic.
After that, I'm seeing prices up to 300 for what looks very similar. I assume up there I'm paying for construction/longevity/interchangeable mounts etc, so remove that from the equation.

What is added by a) the honeycomb & b) the extra depth?

I'm assuming each adds "more diffusion", evens out the light better, presumably at the cost of needing more power from the flashes.
I'm tempted towards the honeycombs - probably swayed by the fact I see them in use all the time (I work in the tv/film industry, but nowhere near the camera) but I'm not even sure I'd have the room for the deeper umbrellas or what it would gain me.

Answer 1

What is added by a) the honeycomb

A grid modifier limits the spread of the light.

Imagine holding a fist full of drinking straws and shining a flashlight through them -- you'd get a beam that spreads very little. The shorter the straws, the more wider the beam can spread. A grid works the same way.

& b) the extra depth?

A parabolic reflector with a light source at its focus gives you parallel rays. A shallower parabolic reflector of the same diameter would have a focus that's farther from the surface. So what you really get from "the extra depth" is a reflector where it's practical to attach the light from the back, as one would with a studio light. To use a shallow parabolic reflector you would mount the light to the shaft in front of the reflector. Note that if you put the light in front of or behind the parabola's focus, the rays won't be parallel, so the light will spread or converge.

Answer 2

The honeycomb makes the light actually harder, larger for the targeted subject, and smaller the further from the target (hope it's clear). On the source side, the angles of the coming light are filtered to a smaller range (hence you can see the honeycomb as a lowpass filter). When you consider an extended subject or a subject in movement, the equivalent of adding the honeycomb is to put the source much further, but without losing as much the power of the source as putting it far.

It is much used because of the light quality, not hard, not too soft.

Deeper means really something when it's a silver reflection, and when there is not diffuser. Deep is not relevant, it's actually the shape (parabolic or something else) AND the position of the light bulb. You might want to check Briese and Broncolor para videos where the light bulb position is changed, and consequently the light quality.

Bigger doesn't actually mean softer (go back on my answer), it means 'slower' shadow transition, but you can have harder light with bigger umbrella.

All those parameters matter.

Good luck.

Answer 3

If I understand correctly, the honeycombs / grid should limit the spill of the light.

I'd like to know what the extra depth would do too.