Do Parabolic Softboxes Really Focus Light? Parabolic vs. non parabolic (and what you need to know about true parabolic) light modifers

In this video Chicago, based photographer John Gress takes an interesting look at how different sizes and different shapes softboxes focus the light and how the light falloff affects the subject and the background of the shot.

Back in June 2020, Gress published a video looking at different types and sizes of softboxes and how they affect the light in different distances. He also explains how he uses different types of softboxes for different functions (you can see the bonus video below).

Out of that video came some questions regarding how different shape softboxes (deeper/wider) modify the beam of light and do more parabolic diffusers really focus the light so much more.

The tests

As Gress works with Elinchrom lights he tested 6 different Elinchrom modifiers starting at 100cm/39″ all the way to a giant 190cm/74″. However, size is not the main issue here. The key question Gress was trying to answer was, are deeper softboxes more directional/focused.

Here are the different softboxes Gress tested in this video:

  1. Elinchrom Rotalux Deep Octabox 100cm/39″
  2. Elinchrom Litemotiv 120cm/49″ Parabolic Softbox
  3. Elinchrom Deep Umbrella (White, 120cm/49″)
  4. Elinchrom Translucent Diffuser for Deep Umbrella (120cm/49″)
  5. Elinchrom Rotalux 135cm/53″ Octabox
  6. Elinchrom Indirect Litemotiv Octabox 190cm/74″

You can see the results in the table below with exposure values for different distances

Real-world usage & the importance of True Parabolic diffusers

Surprisingly enough testing the same modifies in a mock real-world setup seems that all these numerical values make relatively little (if any) visible effect in terms of focusing the light (keep in mind this video is not focused – no pun intended – on the quality of light, just on the question of how focused the light is when comparing different sizes/different shapes of modifiers).

With that in mind, we do want to mention something important here. Not too long ago photographer Karl Tylor posted a video – below (and an article) talking about using parabolic light modifiers for fashion and beauty. What he emphasizes in that video is that not every light modifier that has the word “parabolic” in it acts in the same way and focuses the light in the same way.

Karl Tylor on the benifits of true parabolic modifers

First, it needs to be in the right (true) parabolic shape to really reflect the light correctly, and maybe even more importantly, true parabolic light modifiers come with a center focusing rod and light that typically faces back into the modifier and not at the subject for proper focusing.

These types of lights like the Broncolor Para 133 reflector for example that Tylor uses (which has some cheaper alternatives from other companies like some of the solutions Parabolix or StorbePro although we didn’t test those so we can’t testify for their focusing/quality capabilities) are designed to make the light source considerably more focused.

What is important to remember here is that to be able to really focus the light you will need a combination of a true parabolic modifier and a focusing rod that goes with it to really get you a significantly more focused look and so the different modifiers that Gress tested might give a different quality of light but not necessarily significantly more focused light relatively speaking.

Bonus video: different modifiers Gress uses in his work

As always you can find more helpful photography tips on our Photography tips section and many more light specific videos on our special lighting and modifiers subsection on LensVid.

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