A photo can be technically perfect - sharp and perfectly lit.

But sometimes a photo can do much more than that: it can capture an emotion, the joy of a moment, which would otherwise have flown away with the moment itself. And sometimes that joy is best captured in a blur of movement, an uncontrolled laugh.

In my day job I help companies to become more sustainable. I love the work I do. But sharing in the joy of a wedding - the first moments a couple have as husband and wife - is something I'm loath to let go of.

The blur of a laugh, the sparkle of a very new wedding band: a moment of joy.

(This particular moment of joy is from David & Hester's wedding in Merton College Chapel, Oxford.)