We bought the iPhone 8 Plus a couple months ago in hopes to improve our street photography and add some 4K video to Perpetual Radio, especially with the recent launch of PRN_tech. The iPhone 8 Plus seemed like the ideal choice with it's dual camera system which helps with optical zoom through a longer lens system over the standard wide angle lens found on the 8 and older phones.
We noticed something strange when shooting with that 2x zoom though, in low-light conditions the telephoto lens doesn't activate, and uses digital zoom from the wide angle lens.
The iPhone 8 Plus' telephoto lens has a f/2.8 f-stop over the wide angle's f/1.8 which means it has slightly less low-light performance than the standard camera. This is likely the reason why the default camera app will default to the wide angle lens when taking 2x images in less-than-ideal camera situations.
Our main concern with this is lack of public awareness. As tech journalists and enthusiasts of the latest gadgets, we were unaware the camera system had serious limitations and had been using the 2x zoom often without thinking much about it. Digital zoom isn't great, as it crops the image which ends up killing the overall quality and resolution of the photos. If someone didn't know their optical zoom wasn't working, they'd be taking sub-par images and video without knowing it.
We did some further testing for our episode of PRN_tech on the iPhone 8 and 8 Plus camera systems which you can watch below.