This time I have relevant information 🙂 I am now almost sure of the trigger although I don't know how to prevent it.
As you know my primary suspect have been the phone calls. But what I have accidentally found is that there is AN ACCUMULATIVE EFFECT!!! One phone call between camera activation cause a hardly visible lag. But if there are more and more calls the lag gets bigger!
Today I have called more than a dozen of times since my last camera app activation (yesterday).
And guess what? 14 seconds lag!!!!! Which is almost a record.
After this huge clue, I've dialed several times a dummy number (voice mail and general information. Free calls 🙂). I've spent some seconds in each call (10-15 seconds).
After 7 or 8 calls in a row (dial-15 seconds conversation-hang , dial again...), I've click on the camera app and got 6-7 seconds lag!!!
If only I make 1 call, then it is hardly 1-2 seconds lag which could be considered normal or simply hide it.
My iphone is a 6s, 9.3.2. I've disabled FaceTime just in case but still fails. Also I've repeated this procedure (7-8 calls between camera activation) with mobile data disabled and again I got 5-6 seconds lag.
So whatever the reason is, real phone calls (not only ringing, but a conversation) cause some effect to camera app, which turns out to be accumulative.
This could explain that some people hardly notice it, since not too many people calls frequently...
Any other messy iPhone camera lagger could confirm this behaviour? Some people in this thread have already predicted that a clean iphone would have this problem just for calling...
If we confirm this, then it would be easier to show the problem and confirm if disabling other services could help. Solution could be closer!!