Dan Provost of Studio Neat (makers of the excellent Glif) ran some tests to analyze the low-light performance of the iPhone X's telephoto lens:
Last year, when the iPhone 7 Plus was released, Glenn Fleishman wrote a terrific piece for Macworld about how the dual lens camera system works. In short, when you zoom-in to 2X, the camera does not always switch to the telephoto lens. In some cases (typically in low light scenarios), you will be presented with a cropped image from the wide angle lens instead. This was sacrilege to camera nerds, but Apple would argue that if the cropped image looks better in those low light situations, then that is the correct approach.
Results are impressive:
As you can see, the iPhone X required very little light before it decided to use the telephoto lens. The iPhone 7 Plus required quite a bit more. I used the app Light Meter to measure the light at each interval, which I denote in the video. The app measures the lux, which is a measure of illuminance equal to one lumen per square meter. (I measured from both devices and averaged the results, as the readings were slightly different. I wouldn’t expect an app to function as well as a true light meter, but this probably gets us in the ball park).
Make sure to check out the video to see the lens switching in action. The difference between the iPhone 7 Plus and the X is substantial when it comes to the amount of light required for the system to pick the telephoto lens.
Apple released a new ad in its ‘practically magic’ series featuring the iPhone 7 Plus Camera app's Portrait mode called ‘Take Mine.’ Set in Greece, the video starts with a young woman arriving to visit her grandmother. They sit in a cafe where the young woman takes a photo of her grandmother using Portrait mode, which simulates a shallow depth of field.
The grandmother gasps when she sees the photograph exclaiming ‘What a great photo!’ which gets the attention of others nearby. That leads to the young woman being asked to take portraits of people all over her grandmother’s village. The action cuts between the woman taking photos and the portraits she takes, ending with the tagline ‘Portrait mode on the iPhone 7 Plus.’
The iPhone 7 Plus features a dual camera system that enables a special Portrait mode in the Camera app. Apple has collected tips for using Portrait mode from professional photographers, like this tip from photographer Pei Ketron:
”Portrait mode on the new iPhone 7 Plus creates beautifully realistic background bokeh that rivals DSLRs.” When taking photos of pets and animals she advises, "give your pup some space. Portrait mode uses the telephoto lens, so a distance of about eight feet away is recommended. Have treats ready. You'll get the best results when your subject isn't moving.”
Under the right conditions, Portrait mode can take some wonderful photographs as these demonstrate. The rest of the photographs and tips posted by Apple are available in the Apple Newsroom.