A bride-to-be discovers a reality-bending mistake in Apple's computational photography

Thanks to technological advancements, photography has come a long way from flash bulbs and film. Every time the iPhone shutter button is clicked, billions of operations occur in an instant that results in a photo.

A U.K. comedian and actor named Tessa Coates was trying on wedding dresses when a shocking photo of her was taken, according to her Instagram post shared by PetaPixel. The photo shows Coates in a dress in front of two mirrors, but each of the three versions of her had a different pose.

One mirror showed her with her arms down, the other mirror showed her hands joined at her waist, and her real self was standing with her left arm at her side. To anyone who doesn't know better, this could prove to be quite a shocking image.

What's actually occurred here is a mistake in Apple's computational photography pipeline. The camera wouldn't realize it was taking a photo of a mirror, so it treated the three versions of Coates as different people.

Coates was moving when the photo was taken, so when the shutter was pressed, many differing images were captured in that instant as the camera swept over the scene, since it was a panoramic photo capture. Apple's algorithm stitches the photos together, choosing the best versions for saturation, contrast, detail, and lack of blur.

The final composite image should be the best, most realistic interpretation of that moment. However, since there was a mirror present, the algorithm determined that different moments shown in each mirror were the best for that reflection. That's what resulted in three different Tessas.

This result can be recreated on any recent iPhone and many kinds of smartphone due to the limitations of computational photography dealing with mirrors. Younger generations have figured this phenomenon out and used it to generate silly images for social media.

Update December 2, 11:05 Updated with details about the photo being shot in Panoramic mode, which is why the bride-to-be had time to change position between the shots found in the mirror.