You’ll have seen Shot on iPhone posters before. It’s one of Apple’s regular campaigns, designed to show off how good a camera there is on its phones.

The latest pictures were all taken on one night, Bonfire Night last year, since you ask. Images were shot around the world, from Johannesburg to Shanghai. Since they were taken at night, the emphasis was on the low-light capabilities of the latest iPhone. The thematic focus was the transformative power of dusk, darkness and dawn.

Since low light has traditionally been where posh cameras have thrived and lowly smartphones have struggled, it’s a good place to start. The iPhone 7 and iPhone 7 Plus both have cameras with optical image stabilisation and wide-open f/1.8 apertures, both of which help in low light.

Among the photos that made the cut for the campaign, two were from British photographers. Ruairidh McGlynn is a mobile photographer based in Scotland and Arif Jawad a chemistry student who lives in London.

Ruairidh’s shot was taken in Iceland, in a natural ice cave which offered too good a shot to miss, even though light was sparse. “I was immediately surprised by the handset’s ability to compensate for the lack of light,” he said. “From the moment you preview your frame on screen it is evident that the iPhone camera allows you to capture sharp, crisp images with great colours and tones in low light.”

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It’s a striking image, notable not just for the sharpness of detail on the ice ceiling, but also the brightness of the icicles and the simple silhouetted figure in the cave mouth. That’s before we get started on the elegance of the composition, which Ruairidh takes seriously.

“Whilst taking images on the glacier was difficult and could be very slow, I found that the simplest compositions were often the most time-consuming to capture. For example, we encountered a gas station on the road. Its glowing structure provided a stark contrast to the darkness of the surrounding landscape and sky. It was a really simple composition but as the harsh Icelandic wind and rain battered down it took some time and patience to get that image right by waiting for a break in the severe conditions.”

In a follow-up interview this morning, I asked him if the inability to shoot in RAW in the native camera app would see Ruairidh switch to apps that accommodated it, such as Manual and VSCO. “The greater control in post-production that RAW capture allows is certainly an attractive feature, VSCO integrates this feature into their app really well. I enjoy using the native camera app too much to make the permanent switch, but RAW capture is certainly a feature that I'll start to use more often and alongside the native app.”

I also asked him about low-light capabilities on the iPhone. “The results have exceeded my expectations, I have found that in low light situations during both dusk and dawn that I can continue capturing images well beyond what was previously possible, pushing the camera much further than before. Even into the depths of the night the iPhone 7 didn't disappoint, yielding some great results.”

So did he have any iPhone tips for regular users taking shots a night? He did. First: “For the very best results focus on a single definitive source of light or a homogenous source over a large area also works really well.” He also noted that “reflected or diffused light sources can also help create unique and interesting images.”

The iPhone 7 Plus recently introduced its photographic highlight, the Portrait Mode that artfully blurs the background to bring your subject into sharper relief. Ruairidh suggested: “Try using the portrait mode up close on a bright source of light, I found that worked really well on glowing greenhouses.”

(Arif Jawad (Arif Jawad)

Arif Jawad’s image was taken at a performance at Brixton Jam. “The light was zero to none and it was quite difficult to get the shots that I wanted. It is absolutely amazing to see how quickly the iPhone 7 focuses on certain points even under extremely low lights.”

Arif recognised that low-light shooting is challenging, since, “Noise is introduced, which makes the picture extremely grainy. You definitely need to find light sources to expose shots properly.”

He also had his own tips: “Make sure you have put your focus point on your subject. For portraits, make sure the face is sharp. Keeping the light source in the frame helps the phone to set up exposure faster, helping you to capture that moment sharply at the right time.”

I also talked to Arif about the value of shooting in RAW and apps like Manual and VSCO.

“Shooting on RAW yields the most amount of detail in a picture, no doubt. However, with extremely slight editing, I've been able to manage to take shots that, when compared to DSLR shots, are almost indistinguishable, even by a keen eye. The interface of the Camera app is also the easiest and the fastest to use out of the three applications, which helps me to capture the perfect moment at the right time without any delays and I'd definitely give up a slight bit of quality to gain that advantage.”

Smartphone cameras offer tremendous convenience, whether that’s because you can upload the images you shoot faster than you can with a traditional camera or extra features, such as launching the camera app with your voice (though Siri does not take the shot for you, you still need to hit the button for that).

And there are often extra features regular cameras lack, such as the facility to capture a still shot while shooting video, as you can on the iPhone by tapping the white circle next to the record button. And the iPhone’s Portrait Mode excels in part because it shows a real-time preview of how the background will be blurred as you shoot.

The ultimate comparison for an iPhone is with a DSLR camera. How does the iPhone stand up? Ruairidh said, “The iPhone is very compact, easy to store, the lens is well protected and the user interface is intuitive and quick to use. Those qualities lend themselves well to the candid landscape shots and conditions I enjoy capturing.”

Arif’s take was this: “On days where I forget to bring my DSLR camera with me, I have the confidence to say that I can take similar high-quality shots with the iPhone as I would have if I had my DSLR with me. Things such as adjusting focus points and exposure compensation have become so effortless thanks to the touchscreen.

“With the introduction of the portrait mode on iPhone 7, the potential is that much higher than it was before. As the years go by, iPhone will perform similarly to, if not better than the DSLRs when it comes to taking photographs.”

Personally, I still find it hard to believe that the DSLR will be replaced. However effective features like Portrait Mode are, they are achieved by software and algorithms where DSLR users rely on good glass and the physics of light. Both have limitations, but I’d rather trust the glass.

Mind you, Portrait Mode is a huge step forward in smartphone photography and generates uniquely effective results effortlessly.