After a week of travelling to Rome and Canterbury with a group of well over fifty Archbishops, Bishops and a Cardinal I thought that I’d share one of my favourite pictures from the job. The summit and pilgrimage was organised by IARCCUM (International Anglican–Roman Catholic Commission for Unity and Mission) where the Bishops in their pairs were commissioned by Pope Francis and Archbishop Justin Welby to work together to forge greater understanding and cooperation between the two churches in their respective diocese.

This picture of Cardinal Stephen Chow, Bishop of Hong Kong was taken during a candlelit pilgrimage tour of Canterbury Cathedral a few short hours after we all arrived in Canterbury. Getting photographs lit by candle right is never easy but when it comes off it is always rather effective.

Once upon a time we all used prime lenses with fast maximum apertures but these days I tend to go for f4 zooms because they are relatively lightweight and because the cameras can shoot all the way up to 12,800+ ISO if you are very careful. Fortunately on this bit of the week-long commission I had a couple of fast primes on my cameras with a 35mm f1.8 on one and an 85mm f2 on the other and I’m quite glad that I did because this frame shot at 1/60th of a second and at f2 was possible at only 3,200 ISO.

While I was shooting the candlelit vigil someone asked me how much light I had to work with and I jokingly said “one candela” which then lead to the question about what a candela is as a unit of measurement. I couldn’t remember exactly so I consulted the internet and it turns out that my explanation was pretty accurate – or at least accurate for something I remember learning about in the 1980s!

A couple of days later the Cardinal was back in the Cathedral but this time giving a sermon as a Catholic in the Anglican Cathedral making a start on fulfilling the Commission from The Pope and The Archbishop.

Techie note for people like me: The candela is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10¹² Hz, K_cd, to be 683 when expressed in the unit lm W⁻¹, which is equal to cd sr W⁻¹ or cd sr kg–1 m–2 s3, where the kilogram, metre and second are defined in terms of h, c and ∆ν.