Painterly portraits capture private moments behind steamed windows

Nick Turpin is an acclaimed London-based street photographer. This is an edited excerpt from his book "On The Night Bus" published by Hoxton Mini Press

London (CNN)The pictures in this book were made over three winters between 5.30pm and 7.30pm as commuters traveled home by bus from their jobs in The City of London to the suburbs.

I photographed into the top deck of the bus from a raised platform using a long lens and very slow shutter speeds. It was generally unpleasantly cold and wet.
Standing outside in the dark shooting into the lit and humid interior of the bus allowed me to remain largely invisible to my subjects, they were in their own worlds, sleeping, reading, texting or just staring.
I became aware that their commute was an odd period of anonymous "no mans land" between work and home, a transition from the person known by their colleagues to the person known by their families and friends.
I consider the candid public photograph to be an important social and historical document. There is much debate about the degree to which the photograph can be a document of reality but I believe there is, at the very least, a strong relationship between the photograph and the scene recorded.
While in recent years lens-based artists have used the camera and the computer to record their imagined fabrications, I still think that freezing reality for us to hold and inspect over time undoubtedly remains the camera's best and most rewarding trick.
I have sometimes found myself sitting on the bus staring back through the window at the spot in the dark where I usually stand with my camera.
"On The Night Bus" is published by Hoxton Mini Press