[One (M7) General] ddearce:
How is your weather where you are? is hot? how much?.

The problem appears after you reach 34.5C° (95-94F), you can check the temp of your phone dialing *#*#4636*#*# and then choose battery.

This problem is called "amp noise", and is electrical interference to the sensor, the sensor has a bad shielding.

If they just keep replacing the same sensor (same model, same shielding) the problem WILL come back after some use and degradation of the shielding.

You can correct (sort of) this noise using exposure-controller apps, like Camera FV-5.

To reduce the heat from the phone, and have more time to make a shot or record a video, you can set power save mode on, and limit the CPU.

All of this can HELP but not fix the camera, even replacing the sensors will NOT fix this issue until HTC improves the shielding of the sensor.

This can be helped via FW also, but its a longshot, maybe with 4.4? some people reported to having the problem almost fixed with that.

If in my country was winter right now, I will never gonna find out this, 'cause here we have 8 months of cold, below 16C°, and the phone under 34C° performs great.

High ISO in a phone is a bad idea, little room and so much hot and noise.

The Galaxy S4 have only 800 ISO max, and that's for a reason.

Maybe the problem is the motherboard, or the design itself, and it's too expensive to totally fix it, who knows, but i know for sure, that ISO +800 in a phone is gonna be tricky, and that is why this problem is happening again to people who got the sensor replaced, from all over the world, and in differents time-frames.

Amp noise happens to every camera, even the most expensives, the longer you got the camera on

Wanna do a test? just go to a low lighted room, and turn on your camera and set the ISO at its highest (1600 i think?), and just focus something, but make sure that the corners of your camera are in a dark spot and wait, but do not let the camera go in sleep mode, we want to have ful exposition, and test how fast the sensor will heat up.

Most of the cameras, after 15 minutes or so, wil show some blue-purple amp noise in the corners, that is normal.

If your phone, after 5 minutes or less starts to show purple-blueish spots on the corners, then it's not properly shielded/heat protected, and that duration will go down with time.

PD: If you live in a cold country its obvious that the test will be affected.

Sorry for my english, its not my prim language.

PD2: The explanation of why the screen will turn all purple/red when you cover the lens or enter a dark room is simple, is 'cause the phone, when detects no light at all, it will set the ISO to the max, in order to get some light, that makes the sensor heat up really fast, and if hets up, and had a bad shielding then the noise happens.

The 4.3 "fix" just make this mechanism work backwards, now when the phone detects a lot of dark, or complety dark, it sets iso to 100, to prevent overheating.

And thats why also some users experiment some "flashing" like a disco in some low light conditions after the 4.3 fix, 'cause the phone says:

-OH SHT! THERE IS NO LIGHT NO LIGHT! I MUST TURN ISO 100, MUST FIX THIS HEAT!

but then detects light

-OH WAIT! THERES SOME LIGHT HERE! LETS RAISE UP THE ISO!

but then you just move the phone a little to the left and...

-OH NO! DARK AGAIN, LOWER THE ISO NAO!!

Result: flashing screen disco madness xD