I have been experimenting with bounce flash to provide diffuse illumination rather than passing the light through various materials to diffuse it. This is the latest version of the setup I've been experimenting with. The bowl is lined with a layer of somewhat crumpled aluminium foil with a layer of printer paper on top of the foil layer.
1923 Illustration 1 by
gardenersassistant, on Flickr
1923 Illustration 2 by
gardenersassistant, on Flickr
1923 Illustration 3 by
gardenersassistant, on Flickr
For comparison purposes, here is the latest version of my multi-layer diffuser. This has two layers of "plastic paper" on each of the flash head boxes, then an overall layer of plastic paper and finally a layer of silk. The inner layer in the boxes is around 2cm from the flash head and the four layers are separated by gaps of 2cm or so.
1912 1 by
gardenersassistant, on Flickr
The reflector bowl setup delivers around 1 and 2/3 stops stronger illumination than the multi-layer setup. From tests so far it seems to produce light that is at least as diffused as the multi-layer setup, and possibly better.
As with the multi-layer setup, the focus lights on the Yongnuo YN24EX flash heads are functional, but presumably deliver around 1 and 2/3 stop more light than with the multi-layer setup.
The light-emitting area of the two setups is similar, at around 500 square cm, so the size of the light source appears to be roughly the same size from the point of view of the subject (bigger being better for the quality of the illumination).
The reflector bowl setup covers magnifications from 8:1 to less than 1:1 with no adjustment of the setup. (The illustration below is of an earlier version which did not have the paper lining.)
1921 15 Working distances with Laowa 100 2X and two 2X TCs by
gardenersassistant, on Flickr
The bowl gets in the way about the same amount as the multi-layer diffuser, which surprisingly proved to be not much for the around 2,000 test shots I have done with this particular setup in four test sessions.
There are some examples of images created with this setup in
this post.