The Google Camera app is a pretty decent app to use to take photos on your Nexus device. It's not as great as what you get out of LG, Samsung and others, but the best part about the Google Camera app is that it works on every Android device and can be updated through the Google Play Store. With the release of the Android N Developer Preview 2 just yesterday, we gained a new camera in the release, but better than that, the new camera app is available in the Play Store and will work on any device running Android 6.0 Marshmallow or higher (basically either Marshmallow or N).
There's not a ton of differences here in the app, but the major UI differences come in buttons. The button to switch between the front-facing camera and rear-facing camera has been redesigned slightly. Additionally the shutter button is now a bit different. The inner part of the shutter button is a bit more transparent, and gone is the blue circle. Another change is that when you are shooting in 4:3 ratio, the black bar that houses the shutter button, gallery shortcut and the camera switch, has now changed from a dark gray to straight black. Not a huge difference, and many people probably wouldn't even notice.
The other differences here are mainly in the video section. So now to shoot slow motion, the option is in the pull out menu, instead of in the video UI. The other change, is that you can now take photos while recording video again. This was a feature that was part of the app before but was taken out. Nice to see that feature put back into the camera app for Android N.
Keep in mind that this is a Developer Preview, so a lot of these minor changes we see may not make it into the final release. But where these changes are actually part of the app and is on the Google Play Store, these will likely stick around. The changes are actually pretty nice, but don't change how you use the camera really. Other than the changes to video.