'So the people in China at this time never saw these Western goods. They knew nothing of them. After 1980, Deng Xiaopeng opened up China. The Chinese people now had money but they were buying digital and plastic cameras.

'Out of 100 people who buy cameras, at least 10 per cent know the plastic and digital cameras are a kind of tool, not a masterpiece of design. But they've never seen what else is out there.

'Now they have money, and they see that during that time there were masterpieces being made - so they come to Hong Kong to find them.'

Chan opened his first camera store in Champagne Court in 1970, the only one in the building at the time. He soon opened another store.

Fast forward to today and the ground floor of the Kimberley Road building is filled with shops selling cameras: old, new, small, large, from big-name brands to the rare and esoteric. It's a camera collector's utopia, especially for mainlanders looking to buy vintage cameras they have heard or read about but have never seen.

'About five years after the end of World War Two, the technology of mechanical things started to rise. It wasn't just cameras; it was watches, cars, optics,' Chan said. 'They were masterpieces but not many people could afford to buy these goods after the war, especially Chinese.'

Chan said digital cameras were often the first choice for most people but some were returning to manual cameras to learn about shutter speeds, apertures and focus.

'We were scared that no one would buy film cameras but then the Japanese brands released camera bodies that allow a film lens to fit.'

Most of his mainland customers are from Guangdong, Shanghai and Beijing, Chan said. They are mainly men and professionals such as doctors and accountants, aged 30 to 50.

'Mainland customers tend to ask for certain models. They collect the information online then they come to my shop to look for these European brands. Most of them are looking for lenses because the older lenses can be mounted onto digital camera bodies.'

Chan said mainlanders were primarily interested in pre-1980 models from European brands such as Zeiss, Voigtlander and Leica. And Chan has thousands of cameras to show them - he travelled to the United States and Europe in the 1980s and 1990s, stocking up at camera shows.

Chan said although he has lost business to websites such as eBay, interest from the mainland keeps his doors open - 50 per cent of his customers are from China, with the rest mainly from Hong Kong, Taiwan and Singapore. 'They are willing to pay a premium - the prices are increasing by 10 to 20 per cent.'

Prices for camera bodies or lenses range from a few hundred to thousands of dollars and mainland customers spend anywhere from a few thousand dollars to HK$10,000, Chan said. 'I let them try the lenses first to see the difference between these vintage ones and their new digital models. If they are happy, it makes me happy to help them find what they are looking for.

'Even from 1988, I did business with China News Agency with trade-in cameras because there was no foreign exchange. So I would trade cameras for collectors and people found out about my store.'

A brass lens for a large-format camera the size of a rugby ball and weighing at least 3kg sits on Chan's desk. 'An Indian broker brought it here to me and I bought it... someone from Beijing, Shanghai or Guangdong will buy it from me.

'Most of the camera shops don't stock this type of stuff. It's very hard to get. Other stores get stock, then sell it straight away, but that's not what I do. If I get two, I will only sell one and I will keep the other. I have a special place where I keep my collection.' With no immediate plans to retire, it looks like Chan's pre-loved camera business won't fade any time soon. 'It's hard for me to retire because I see so many friends here. People that I met 20 years ago still visit and bring their children and grandchildren.'