When Italian production company Pesci Combattenti was tasked with launching a fresh current affairs programme for leading channel RAI1 last summer, CEO and art director Riccardo Mastropietro immediately started thinking about which lenses would work best with their trusted Canon Cinema EOS Cameras to bring the stories to life. Sette Storie (Seven Stories) would place a unique demand on its cameras and crew, as the teaser interviews would be conducted while journalist Monica Maggioni and her interviewees walked through city streets.

The weekly broadcast, inspired by the French programme Conversation Secrète, explores the pressing issues of the day. Studio interviews are preceded by the host and interviewee meeting for the first time on the street, shot with hidden cameras, to create a feeling of eavesdropping on a private conversation.

"There were a number of difficulties to overcome, such as how to shoot, in a single take of around an hour, a walking interview almost one kilometre long," says Riccardo. "It was necessary to have high quality, cinematic lenses with an extensive focal range, but at the same time something that was easy to pass on in a relay race among the camera operators."

Riccardo and his team specialise in factual docuseries and documentaries. They say that filming huge names around Italy – from former Italian Prime Minister Giuseppe Conte on the streets of Rome to pop star Mika by Florence's iconic Ponte Vecchio – has been a true challenge but a "great adventure".

Turning to Canon's Compact Cine Servo range, the crew teamed their Canon EOS C300 Mark II cameras with CN-E70-200mm T4.4 L IS lenses and Canon Extender EF 2xs (now succeeded by the Canon Extender EF 2x III) to achieve a high-quality aesthetic with great versatility and speed of use in the field.

For each episode, Riccardo and his team were tasked with capturing an hour's worth of footage – as interviewee and journalist chatted while walking through bustling Italian streets – which would then be edited into a 20-minute introduction to the beginning of the studio-based programme.

"It was to be shot in a sort of spying or paparazzi mode," explains Riccardo. "The cameras were hidden from the interviewee during the walk. Although, of course, they knew we were filming, we had to stay very far back from them so as not to be discovered." At times this meant the camera operators were 100-200 metres away from their subjects, although when shooting in narrower streets, such as in central Rome, this came down to about 50 metres.

Adding a Canon Extender EF 2x offered the expansive focal length needed to film at a distance, extending the 70-200mm range to 140-400mm, while still keeping the set-up compact enough to be nimble in the field. "That was a flexible lens, light enough so we could run fast on the streets easily, with stabilisation providing a spectacular result in terms of image quality," Riccardo says. "With this programme, there was zero possibility of redoing the interview shots. We achieved the match we needed with the Canon EOS C300 Mark II and the Canon CN-E70-200mm T4.4 L IS lens."

The team had just an hour to film a natural conversation between Monica and her celebrity guests, while contending with all of the unpredictability of busy city streets. "It was a very challenging production because, as we were outside, there were a lot of things you couldn't control," says Riccardo. "Things change from how you'd planned them just 10 minutes earlier. There are people shouting, there are cars, there is a van blocking you. You must be quick to change your mind, change your idea, and find another spot to shoot from."

Typically, the team had one of their Canon EOS C300 Mark IIcameras on a tripod and the other three handheld, so they relied on image stabilisation to capture sharp footage. Alongside this, they also shot BTS-style shots zooming in and focusing on the pair in conversation. "To set the story, we used a lot of zoom shots and focus adjustment that would usually be cut in the edit, but which were the language of this format," says Riccardo. "We used a lot of this in order to make the audience feel that this filming was real. This was the aim of the format, for the audience to feel that they were really hidden, that they were really spying on these two people walking on the street."

When filming high profile guests for Italy's leading broadcaster, reliable equipment that delivered outstanding picture quality was essential. Riccardo found the 4K-optimised image and colour technology in the Canon CN-E70-200mm T4.4 L IS lens matched beautifully with the Canon EOS C300 Mark II's Super 35mm CMOS sensor.

"One of the main features of the EOS C300 Mark II with CN-E lens was the high performance of the camera's sensor," he explains. "We shot some interviews with very low light or sometimes at night, filming in 4K in order to magnify digitally during the editing process, rather than using the Canon Extender EF 2x. No matter the lighting conditions, the camera is really sensitive, in both HD or 4K. We had great images with light equipment."

This sensitivity came into its own when filming one of the series' most important interviews. "We were called just 12 hours before, because it was with our former Prime Minister Giuseppe Conte," says Riccardo. "Where he would be moving had to be really secret – nobody could know. The crew didn't know who they were filming until they got to the site of the shoot. And we shot that at night, for extra security, close to the Colosseum. We did a great job with little lighting because, I can tell you, the street from the Colosseum to Della Cina Roma is really dark."

After the high-octane shoots, there was always a wonderful reward for the team. "The best part of this project was the face of the VIP at the end of the shoot because they weren't able to see the cameras during the whole interview," says Riccardo. "They were really surprised at how far away and hidden we were. I'll never forget filming like this because it was really hard, but it was a format full of adrenaline. It has been a great adventure."