I've heard it an heat up after prolonged gaming periods of intensive gaming @EllyH
However I've not come across anything yet saying it heats up from using the camera.
As you say it's a warm day and your hands add heat I would soft reboot the phone by turning it Off and On and then try again.
Please let us know how you get on.
Current Phone ~
Samsung Note 20 Ultra 5G SM-9820 _256Gb SnapDragon 865+
Samsung One Ui 2.5/ Android 10.
For what its worth, my Note 20 (not ultra) also has heating issues when using camera, my wife's Note 9 didn't have any heat ups, we both were clicking pics at the same location. It looks like camera is using a lot of processing power and heating up the phone..
Also have noticed heating issues when using wireless 10w charger at night, phone looks like was hot for the whole night.. 😞
I am also experiencing the issue with my Note 20 Ultra heating up. When I doing a lot of scrolling thru webpages the phone can get very warm. Its a little concerning because I wonder if that is reducing the life of the phone. Heat is the enemy to electronics.
It is the Exynos chip probably...
This is what cpu monitor says with just the app open, not touching the phone: https://i.imgur.com/pxXraQR.png
29 degrees and 23% cpu usage.
This is after giving the screen just 1 quick tap: https://i.imgur.com/nXXyA0h.png
Temp was about the same, since it was just 1 short spike. But as you can see, the cpu usage spiked to 68% just from 1 tap.
Imagine this while scrolling through apps.
Leaving the camera app on, on both my 3 year old note 8 and note 20 ultra, after only 3 minutes the note 8 only lost 1% battery and was stable at 32 degrees. The note 20 however had lost 6% already and was at 40-41 degrees and was still very slowly rising.
I don't think you understood my comment. My battery drain during idle is fine. The temperature during my usage is manageable.
I was just pointing out where the high temperature comes from, 'especially' when using the camera.
The temperature is a real problem using the camera, as the heat, at least on my note 20 gets uncomfortable to touch and it drains the battery a lot quicker than it should.
"The note 20 however had lost 6% already and was at 40-41%" < the last part should be 40-41 degrees not %.
Edit: I should add that after explaining this and showing the screenshots from my previous comment + the battery usage screen. The samsung support made me reset my phone. Since then I haven't heard back from them :))