Every MT-24EX user should check out Rob Ault's brilliant adjustable diffusers before making one of his/her own.
These are the items that he uses in his rig:
1. Kaiser Bounce Flash Shoe x 2
2. Gary Fong Lightsphere II Inverted Dome(Translucent) x 2
3. Velcro Sticky-Back Hook & Loop Fastener
4. Blu-Tack Re-usable Adhesive
5. White Styrene Sheet
Rob Ault's macro rig.
Top view. Rob has two versions. The ones you see above are with the part of the Gary Fong domes cut off. The ones you see below are uncut i.e complete domes.
A piece of styrene sheet hot glued to Gary Fong Inverted dome.
Side view. The Gary Fong dome is attached to the MT-24 adapter using blu-tack. Rob has since replaced the blue-tack on top of the flash head with hook and loop velcro so he can raise or lower the Gary Fong to adjust the level of diffusion he wants.
You can also see from the image above that he uses Kaiser bounce flash shoe to raise the MT-24EX flash head higher.
Here is a gif animation showing you the amount of diffusion he can get by just adjusting the diffuser by raising/lowering it. Again, back to macro lighting 101: it's not just about how big your diffuser is, but also how close it is to your subject! The subject was a red berry by the way.
There were 7 gif files in this animation. You can see in the first one that it has the strongest specular highlight and smallest catch light size of all. As you lower the diffuser further, you can see clearly that the specular highlight becomes less and less harsh, while the size of the twin catch light becomes bigger and bigger. The last one (number 7), of course, has the mildest specular highlight and biggest catch light size.
Ladybird. The lighting is simply fabulous!
A damselfly covered in morning dew
Another damselfly shot
For more info, check out Rob's blog posts on MT-24EX diffusers:
New MT-24EX Diffusers - Part 1
New MT-24EX Diffusers - Part 2
New MT-24EX Diffusers - Part 3
New MT-24EX Diffusers - Part 4
MT-24EX Diffusers - Update
For more ideas on macro rigs and flash diffusers, check out my post on "More Macro Rigs"