Share your experience!
I don't like new camera app layout in Marshamllow. Maybe it's better but I made too much mistakes when I'm using touch focus and camera slides to other mode accidentally.
So, my question is: Can I install older camera app (from Lollipop) without problems?
Also (but this is subjective opinion) I feel that new camera takes a little worst pictures than before. I'm I wrong?
No, you can not revert to the previous version of the camera app. not unless you find an apk of it and sideload it,. though I rather suggest you take a look at other camera apps in google play (ex. Camera Super Pixel)
the image quality is really subjective, most people you see here complains of bad quality , and people who have good quality are on their social medias uploading the pictures.
http://www.sonymobile.com/global-en/xperia/photography/low-light/
http://blogs.sonymobile.com/tag/photography-tips/
http://www.sonymobile.com/global-en/xperia/photography/
http://support.sonymobile.com/global-en/xperiaz3/dm/take-great-photos/
You can use third party apps that are similar to what Sony's UI 1.0 used to be. As for qualtiy, use different camera settings.