The Nexus 6P / Nexus 5X users can now get their hands on the new Pixel Camera app, seen on Google Pixel and Pixel XL smartphones. The XDA folks have ported the app to work on 64-bit devices running Android 7.0 Nougat. However, you will not get all the features from new Pixel smartphones. The great thing is that it does not install on top of your stock camera app and can be removed at any time.
All you need to try out the new app is a 64-bit smartphone running Android 7.0. You can get the Google Pixel camera app on your Nexus 6P/Nexus 5X here. The official Google Camera app from the Pixel/Pixel XL system dump is modified to work on ARM64 Nexus devices running 7.0+. This includes the Nexus 5X and Nexus 6X, but excludes the Nexus 5 or Nexus 6.
The Google Camera 4.2 [Pixel camera app] comes with several tweaks and changes. Here are some pros and cons:
1. The grid view button has been moved from the Settings menu to the viewfinder. Users can choose between three different types of grids – 3 x 3, 4 x 4, and Golden Ratio. 
The new ‘grid view’ button is placed between among the timer, HDR, and flash settings, in the top right corner of the screen. It is also available in video mode.
2. The UI tweaks include a repainted [mostly white] Settings menu, and a transition animation when switching between the front and rear cameras.
3. AE/AF lock: which can be triggered by long-pressing anywhere in the viewfinder. It allows you to maintain the same focus point while re-framing your image or refocus without changing the current exposure settings.
4. Manual exposure slider: It allows you to adjust the exposure while shooting videos.
5. The updated Camera app does not allow you to record 4K videos or 1080p videos at 60fps with EIS ON. EIS is still limited to 1080p videos at 30fps.
6. The burst mode doesn’t seem to work. Holding the shutter button down does nothing.
7. All animations feature a Pixel phone.