I wanted to maximise the soft light from my flash gun but had to be able to easily move the light source around with me, so a brolly or softbox was not viable. I therefore decided on a large diffuser, that also utilises bounced light from any walls or ceilings. This telescopic diffuser compacts down to fit in a camera bag with it's own protective case to avoid being crushed when on the move.

The diffuser fits my Yongnuo 565EX flash, but I believe that it will fit some other models too. Having said that, the design can easily be modified to fit other flash models by slicing the adaptor part below the rim and lofting a template of your flash face to it.

My first attempt at this used a "tight fit" to hold the pieces in place when extended, so it simply and quickly slid into the extended position. However getting the right tightness which lasted permanently was elsusive and after a short while it kept collapsing unintentionaly. This version has a locking mechanism for each layer, but this means it takes a little longer to unpack and get ready to go than I would like, so any suggestions for improvement would be welcome.