At the age of 19, Katznelson began working in commercial photography in Copenhagen, undertaking roles including lighting and camera assistance. He briefly studied political science at Aarhus University before pursuing filmmaking, shooting short films with director Kaspar Munk. He subsequently moved to the United Kingdom to study cinematography at the National Film and Television School, graduating in 2000.
Following his graduation, Katznelson worked across television drama and feature films. His early credits include This Little Life (2003), Shoot the Messenger (2006), Driving Lessons (2006) and Miss Austen Regrets (2007). His cinematography on Shoot the Messenger, directed by Ngozi Onwurah, received the BAFTA Award for Best Photography and Lighting – Fiction in 2007.
Katznelson’s television work includes the first series of Downton Abbey (2010), for which he received an Emmy Award for Outstanding Cinematography for a Miniseries or Movie, alongside recognition from the Royal Television Society. His subsequent credits include The Night Watch (2011), Game of Thrones (2011), Burton and Taylor (2013), 11.22.63 (2016) and Electric Dreams (2017).
His feature film work includes A Boy Called Dad (2009), Faintheart (2008), In Fear (2013), The Anomaly (2014) and 23 Walks (2020). He has also worked on international television productions, including Avenue 5 (2020), It’s a Sin (2021), The Midwich Cuckoos (2022) and The Tattooist of Auschwitz (2024).
In 2021, Katznelson worked as director of photography on The Rescue, the documentary directed by Elizabeth Chai Vasarhelyi and Jimmy Chin about the Tham Luang cave rescue in Thailand. His other documentary credits include Village at the End of the World (2012), on which he also served as co-director, and One to One: John & Yoko (2024), directed by Kevin Macdonald.
His more recent work includes the television series MobLand and the feature documentary One to One: John & Yoko. His career encompasses scripted drama, feature films and documentary filmmaking across British, Danish and international productions.
David lives in London and is also a member of the Danish Association of Cinematographers (DFF).