Diffuser Design

The design of these diffusers and how they actually diffuse light have not been scientifically proven and only based on my experience of using them. There were some certain things I wanted to address while designing them:

Diffusion

This was obviously the main reason for designing these, and the most common way of diffusing light is by spreading it out over a large surface area. In my design I created a diffusion face which is some 4-5x bigger than the flash face itself. While designing the size of the face I considered the size of the subject, and where the MP-E65 lens is concerned the subject will be very small, so going too large on a face design seemed illogical to me.

There is one important thing to note about my particular design for diffusion and that is that I did not want to over diffuse. A lot of people go a little over the top when it comes to diffusion which in some cases may be fine but, from my experience I've noticed that images that are over diffused provide a very flat image which has little contrast and are less pleasing to look at.

The diffusion face design itself has a graduated thickness, with the thickest part being in the middle(ish) of the face which is where the strongest part of the flash light is projected. Most other diffusers have a constant thickness across its face which gives you a false sense of diffusion because you are not only reducing the hot-spot in the middle but you are also reducing light around the edge, which in turn means you have to use much more flash power (see diagram below).

Because the diffusion faces are 3D printed there are some limitations on how thin you can go with the material, however they are thin enough to allow enough light through so that the focusing lights are usable, at least at the low to mid magnifications.

Make them usable at high magnifications

The MP-E65 lens is capable of very high magnifications (5:1) straight out of the box so there was no point creating a diffuser that would only illuminate subjects at 1:1. The problem with trying to light a very small subject is that not only is light very limited, it usually also only gets directed onto the subject from above or sides, rather than in-front of it. in an ideal world, what you really need is a light coming straight out of the lens which is not really possible so, with this in mind I designed the angle and shape of the diffuser so that at least the edge of the diffuser is as close to the lens as possible but not too close to produce glare.

Robustness

When working in the field you are always having to get into the most awkward of places to get the best shot, which can also mean pushing through branches etc so, robustness is essential unless you want to rebuild your diffuser! My final DIY diffuser made from acetate sheet and a piece of paper for the diffuser was fairly robust but quite flimsy, however with this new 3D printed design they are built to last most normal macro adventures!