This image was captured at 3am during a night in early May. I was intrigued by the way that the Shard was framed by the underside of London Bridge and the stairs and walkway leading down to the embankment.

I used my Canon 5D Mk 4 with EF 17 - 40 mm wide angle lens, ISO 100, F9. F9 is my preferred aperture for this sort of image, providing adequate depth of field whilst being the ‘sweet spot’ for optimal image definition for most of my lenses. ISO 100 was chosen for minimal graininess (‘noise’).

The lighting conditions were challenging with a very wide dynamic range, the white lights on the stairs and walkway in particular being exceptionally bright. With the camera firmly mounted on the tripod and composition determined and manually focussed it was time to begin the exposures. The lighting underneath the bridge was changing colour at set intervals, so having decided that blue would work best, I needed to commence the long exposure sequences as soon as the lights turned blue. With the camera in Aperture Priority mode I captured the first image at the metered exposure, then changing to Bulb mode (necessary for exposures longer than 30 seconds) I took the second shot at double the metered exposure. I then changed to Manual Mode, with Highlight Alert enabled (in which any overexposed highlights blink in the camera’s displayed image) and took a shot at half the metered exposure, and then four more, halving the previous exposure each time until, finally, I had a very dark image in which none of the highlights were blinking. I now knew that I had covered the entire dynamic range of the scene.

After downloading into Lightroom I decided that I would not need to use the overexposed image as there was enough shadow detail. The remaining five images were opened as a stack in Lightroom and combined as an HDR file before being transferred to Photoshop for final editing in Camera RAW, luminosity masking etc.

Judges comments: 'This is not just another image of the Shard at night, there is real mastery in evidence here. (I appreciated this remark - even if it is untrue!) There is so much to appreciate about this image, I particularly like the way the main subject has been imaginatively framed by the bridge, and the stairs and walkway - all coming together in a considered and successful composition. The challenging lighting conditions have been expertly handled.'

Wymondham Photographic Society meets on Tuesdays at the Dell Bowls Club. For more information visit www.wymondham-ps.org.uk.