On a Wednesday night two weeks ago, Zouk in Clarke Quay is packed to the gills.

A capacity crowd of 2,500 people has turned up for Liquid Nights, a showcase by Hong Kong-based music label Liquid State. They are there for DJ megastars, Dutchman Rehab and Norwegian Alan Walker, who are spinning back-to-back sets.

There to capture the party mood is Zouk's usual go-to photographer Afiq Omar, the 31-year-old founder of Colossal Photos, the premier nightlife photography collective in Singapore.

Figures are not available for the number of people who ply their trade after hours. The more traditional night-shift roles include factory workers, paramedics, police officers and hospitality staff.

After trailing Mr Afiq on the job for a night, The Sunday Times discovers the different demands that stem from working at night and a different side of Singapore that these people see.

He started out seven years ago as a gig economy worker - freelancing for nightspots such as Zouk, when it was still in Jiak Kim Street, and the now defunct Kyo in Cecil Street.

As nightlife photography is a niche job, it is commonly farmed out to non-specialist freelancers.

Ministry of Manpower statistics show that the self-employed made up 8 per cent of the workforce, or 182,100, people last year.

But Mr Afiq turned his gig job into a viable full-time business in 2013, with an office in Arab Street. The company now has 30 employees, of whom nine are full-timers.

Aged 21 to 35, they are spread across the company's three arms: nightlife, weddings, and corporate and commercial photos.

Because of the work of people like Mr Afiq and his team, nightlife photographers - armed with cameras at every club night, big or small - are now an inextricable part of the nightlife scene here.

Colossal Photos' nightlife team typically shoots an average of 25 to 30 events a week across 18 venues, with each shoot lasting two to three hours. Photos are edited by a team of editors, watermarked and delivered to clients within two days.

Nightlife operator Joshua Pillai, 37, who has been in the scene for the past decade, notes: "In the early days, there were only freelance photographers and their shooting style was very straightforward."

The co-founder of retro-themed clubs Nineteen80 and Pinball Wizard adds: "But people like Afiq and his photographers changed the game - they understand that it's not just about taking group photos.

"They are equally adept at capturing the real emotions of the people on the dance floor and the energy of the room and the DJ playing."

Mr Pillai, who is also the former music director of nightclub Ce La Vi, now uses Colossal Photos exclusively for events at his establishments.

Like what many other clubs do, the photographs are uploaded on the club's social media pages the next day or a few days after to increase buzz, and, ideally, patronage.

"People tag themselves in the pictures and share them on their own social media channels, because everyone wants to see and be seen," says Mr Pillai.

"We do it to remind our guests of what a good time they had and to keep them coming back, but it's also to attract a new audience and show them 'hey, this is what you missed out on,'" he says.

Mr Afiq, who is getting married next weekend, says he never expected that taking photographs in a club would become a viable profession.

For him, being in the club is "about being a spectator in that realm, you have a bird's eye view of everything".

He adds: "It's the lights, people, colours, atmosphere and energy - those are the things I'm drawn to. And through my photographs, I can tell any story I want."