With his tousled shoulder-length dark curls and his laid-back manner, Mark Simmons could easily pass for a rock star.

Indeed, he is a well-known figure in Bristol's music scene – but not for his instrumental or vocal skills.

Mark is a virtuoso of the camera. Over the past 25 years, he has been photographing scenes and people around Bristol. He is renowned for his social documentary style of photography and his iconic images of renowned local bands such as Massive Attack.

Today, sees the launch of an exhibition of his work at the Grant Bradley Gallery in Bedminster called Bristol In Black And White. It consists of an selection of photographs from his recently published book of the same name.

"There's always something to photograph in Bristol," says Mark, who lives in Montpelier. "Sometimes it's just people being themselves in a real way – maybe a couple having an argument. There can be a real power in that moment of honesty, and that's what I try to capture."

We're talking at Mark's studio in a former fire station in Bedminster. On the walls around us are examples of his work, which include studio portraits of individuals and families and also studio images of Bristol music stars such as Roni Size and the aforementioned Massive Attack.

Mark, 45, is a well-known figure in the Bristol art and music scenes. What few people are likely to know about him, however, is that he originally came to the city to study chemistry at the University of Bristol.

"You know how it is," he says, "your parents get you to do O-levels and A-levels and then they want you to go on to university.

"I was quite good at chemistry, so I decided to do a degree in it."

Mark might have ended up spending his days in a white lab coat looking at the contents of test tubes if it hadn't been for his uncle.

He recalls: "My uncle Bill gave me a Rollei 35mm camera when I was 18. He was a keen amateur photographer with his own darkroom. As a result of watching him, I realised that photography was something you could do seriously.

"Then when I was at Bristol University, someone taught me how to develop and print photographs.

"Photography became my hobby, and then my career."

Although Mark decided against pursuing a career in chemistry, it seems that a remarkable alchemy occurs when he gets behind the lens of a camera. Ordinary scenes and people in Bristol are transformed into something special.

A street of terraced houses in St Werburgh's in which some boys are playing football on a misty day takes on an almost Victorian quality in a photograph by Mark. There's something humorous and unexpected about a picture of two workers from the Barton Hill Settlement Cafe in which one of them is holding a magazine called Me to her face. In another photograph, an old lady in a headscarf gazes into the lens holding a wedding photograph of a smiling young couple.

"That's Minnie," says Mark. "I photographed her outside the Watershed in Bristol. I used to see her there quite often, and one day I asked if I could take her photograph.

"She agreed, and then pulled out a small photograph that she also wanted in the picture. It was of her with her husband on their wedding day."

The photograph is a striking example of the way Mark's photographs capture the essence of his subjects while at the same time bringing to them an unexpected beauty.

How does he do it? Mark shrugs his shoulders: "I'm not sure. I think I'm a pretty approachable and non-judgemental, and I suppose it helps if people feel relaxed when you're taking their photograph.

"I work quite instinctively. I was never taught photography, so I've had to learn by experience and learn my own rules. I try to be aware of how people are reacting to what I'm doing."

Maybe Mark's subjects also sense that there's something honourable about him and that he wouldn't take a photograph that made them feel uncomfortable.

He is certainly not a name dropper.

As we talk about his pictures, it is clear that he has known people like Massive Attack's Grant Marshall (Daddy G) and Robert del Naja (3D) for many years. It also becomes apparent that he has known the graffiti artist Banksy for some time, too. Yet he diplomatically refuses to say much about any of them and I suspect that this isn't just because they're now internationally regarded for their work.

Mark's talents as a photographer are not confined to the settings he chooses for his 35mm Nikon FE2 camera.

He also brings out the best in his subjects by treating them with respect – whether they are famous faces or an old lady with a tattered wedding photo.

Bristol In Black And White – A photographic exhibition by Mark Simmons, takes place until January 9 at The Grant Bradley Gallery, 1 St Peter's Court, Bedminster Parade, Bristol, BS3 4AQ. Open Monday to Saturday from 10am to 4pm. Tel: 0117 963 7673 or go to www.grantbradleygallery.co.uk

Mark Simmons' book Bristol In Black And White is published by Tangent. Price £15, paperbac