Cinemagraph Timelapse Mashup in Photoshop

Just realized today that I could "stabilize" a timelapse in Photoshop by adding a layer on top of the video groud and apply a layer mask.

How to make a timelapse in Photoshop is illustrated in a lot of articles online - but I have never seen this technique. It gives you some interesting creative options - like keeping the the foreground bright while the sky goes dark.

It gives the timelapse a cinemagraph look which is quite cool I think.