[HTC One Mini 2] xxxmadraxxx:
Back again!

OK. I've done a bit more investigation on this, so here are my findings:

1: It really doesn't look like a RAM issue. After using all three cameras [Default, HTC Camera & Open Camera] interchangeably for about 20-30 mins, the phone is reporting average memory use of 594MB [72%] with all three camera apps way down the list of memory hogs:

* Open Camera --11MB average. 54MB max.

* Default Camera --4,9MB average. 153MB max.

* HTC Camera --775KB [KB not MB!] average. 42MB max.

So Open Camera is using the most RAM on average [HTC Camera barely using any], but the Default Camera is using the most RAM at peak.

Onto performance. This is from a fresh reboot, with no other apps opened:

* Open Camera --launches in about 10secs the first time and GUI becomes responsive within about another 3-5. Focus and picture taking seems to require about a second. So, slow but just about acceptable performance. Oddly, on subsequent launches [even after being manually quitted] it launches almost instantly and performs almost as snappily [pun intended] as it does on my HTC One M&.

* Default Camera --Sometimes launches instantly. Sometimes I get a grey screen for about 20-30 secs. However GUI seems very unresponsive. When moving the camera, or changing orientation, I often get a frozen image on the screen for several seconds, or screen goes black and camera crashes. When it crashes, it wipes out my custom desktop image and I have to set it again.

* HTC Camera --Launches almost instantly at least as far as an image appearing on screen goes. However the focus ring does not appear, nor shutter become active for about another 10 secs . Once GUI has all appeared, it seems suitably responsive, although focussing and shutter firing is slightly slower than Open Camera. Still acceptable though.

Now. Here's the interesting bit. If i want to review an image I've just taken, by clicking on the thumbnail:

* Open Camera --takes about 20 seconds to launch to the image preview screen [the one with the "edit, share, info, etc" buttons], which is very unresponsive, with any button clicked there, taking several seconds to do anything]. And, once, the image preview screen crashed [taking custom desktop pic with it again!]. It also takes a similarly long time to return to the camera from the preview screen.

* Default Camera --Assuming I can get the GUI to settle down enough to actually take a photo AND it doesn't crash [which is a rare occurrence!].... doesn't seem to offer any way from within the app to review the last taken image.

* HTC Camera --Takes slightly less time than Open Camera from clicking on thumbnail to open image preview screen and, once opened, image preview screen appears more responsive than it did when accessed via Open Camera. However, when returning back to the camera screen, I now have 2 rows of camera controls along the bottom of the screen, which I can only restore to normal by changing to another camera mode and then back again.

So, all in all, on this particular Mini2, I'm not having much joy with the camera at all:

* Open Camera --seems the most reliable, but can be a bit slow to launch and quit. And previewing images really brings things to a snail's pace.

* Default Camera --is frankly unusable. Slow to launch. GUI freezes continually. Crashes all the time and has several times forced a reboot, it's frozen up so bad.

* HTC Camera --a bit slow to launch and become responsive, but quite 'snappy' [I did it again!] in use. Badly let down though by the visual glitches to the GUI caused when previewing images and returning. Very low memory footprint [according to system settings].