Why won't Apple enable Portrait Lighting for older iPhone photos?

Portrait mode photos taken on the iPhone 7 Plus could be edited with the iPhone X and iPhone 8 Plus, if only Apple felt inclined to enable the hidden feature. The new Portrait Lighting effects – which replicate the impact of different types of creative lighting on an image – were launched as a feature of the new 2017 iPhones, but left images taken with older models out in the cold.

That prompted developer Steve Troughton-Smith to go hunting to see if he could change that, or if there was any practical reason Apple was not allowing it. Currently, you can take Portrait mode photos on the iPhone 8 Plus or iPhone X, and edit them with the new Portrait Lighting effects in the gallery app on those phones in iOS 11.

However, even with the iOS 11 upgrade, you don't get the same Portrait Lighting effect options on the iPhone 7 Plus. That's despite Troughton-Smith discovering that in fact the depth data in the photos is the same. He found that by making a tweak to the metadata in the saved iPhone 7 Plus image, then using AirDrop to send it to an iPhone 8 Plus or iPhone X, he could unlock the Portrait Lighting options too.

It has prompted questions as to why Apple might have elected to leave the feature out when it upgraded the iPhone 7 Plus to iOS 11. One of the key messages the Cupertino firm had about Portrait Lighting when it was announced earlier this year was that the beta effects are processor intensive. Rather than just applying filters, Apple says, it's using an AI that was trained on professional lighting methods to modify each shot.

As a result, it's possible that the functionality was left out of the iPhone 7 Plus upgrade because it would've been frustratingly slow to process. However, that doesn't explain why photos taken on the iPhone 7 Plus, and which have all the depth metadata those captured with the iPhone 8 Plus and iPhone X do, can't be transferred to the newer, more powerful devices and edited there.

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The good news is that, should Apple feel inclined, it could readily change that. With little in the way of technical difference between images from the different phones, it would simply be a matter of updating how the gallery app on the iPhone X and iPhone 8 Plus responds to the metadata on iPhone 7 Plus shots. Of course, whether it actually decides to do that, or opts to maintain an artificial barrier between the two generations, remains to be seen.