A periscope lens uses a prism to flip the light 90 degrees and send it down a tube to a sensor located at the bottom of the tube. The tetraprism flips the light 90 degrees, sends it sideways, and then flips it 90 degrees again back to the original axis.

It's a neat trick, has better light efficiency than a periscope, and keeps them from needing a camera bar instead of a bump (like the Pixel).

That said,... a periscope usually allows for zoom across some range, while the tetraprism basically gives you an extended telephoto fixed lens of 120mm eq..

At any rate , the two techniques are in fact different.

Missed the Spatial Video recordings, the after-the-fact Portrait mode, and the 24MP HEIF default option, all nice things for photographers.

Also mixed on the side button change, but being able to trigger Shortcuts with the thing is going to make a lot of people happy.

Also missed on the improvements to the GPUs with hardware ray-tracing, which some of the gamer-types are going to enjoy.