A lot of android phones have a manufacturer provided camera app which has special abilities - for example, it uses private API's to adjust focus, do zero shutter delay capturing, select which camera to use on 'quad camera' phones, do 'auto expose on faces in the scene', do various HDR in signal processing hardware that regular apps don't have access to, etc.
Any app which just uses the android camera API doesn't have access to this stuff - and usually ends up with very poor quality images as a result. On my phone, apps that use the android API can't adjust focus at all, which makes even things like a barcode scanning app useless. Things that say "please take a photo of your ID card in this box" are unusable!
Which device is this? Focus control has been a pretty basic API element since v1. Unless the device is reporting that it has a fixed lens erroneously, that is super weird.
Having said that, the Camera subsystem is most certainly subpar on Android. It is crash prone, only recovering after a full system reset, which makes developing anything novel a giant pain in the ass. It also is full of random bullshit even if you're using Google's anointed, in-house devices. I remember an update suddenly randomly yielding frame rate capability values multiplied by 1000, chaos monkey style. Code ends up being littered with "If this bullshit device on this bullshit version, then...". It's a gigantic waste of time.
And then as Google started trying to differentiate their own devices with exclusive imaging features, things really started going off the rails.
So in such cases, why not just use a camera activity or at least expose a configurable choice for which experience the android user prefers? It is unfortunate that the camera API clearly needs more work though.
Any app which just uses the android camera API doesn't have access to this stuff - and usually ends up with very poor quality images as a result. On my phone, apps that use the android API can't adjust focus at all, which makes even things like a barcode scanning app useless. Things that say "please take a photo of your ID card in this box" are unusable!