Re: True Tone Yay or Nay?
Yes it does affect battery life. It's worth the penalty though.
I abhor night shift. Never liked it. However, true tone is great because once you understand how it works and why it's necessary it's hard to do without it! Think about looking at a piece of paper. It's diffuse and its tint is dependent upon the ambient lighting. A static white point is fine in an office or studio but our phones aren't stationary. The screen will always appear as a piece of bright white paper while illuminated by the ambient lighting. If you have incandescent lighting or CFL/LED lights with warm white (approx 2700k) color temperature, the display's white levels will indeed look warmer. So will the paper. Outdoors, the color temperature is very cooler and the display again will reflect this. This is why a normal display that looks white at home will look much different in the office or outdoors.
There is a battery hit because sensors are constantly polling the ambient light sensor and the controller has to dynamically shift the display's color temperature. If you want the absolute best battery life turn it off as well as auto brightness. The extra 10 minutes (at most) you gain of on screen time at the end of the day (IHMO) is NOT worth the trade off!
Also, when the screen shifts brightness and color, the increments are much smaller so it's not nearly as harsh as other phones.
Finally, if you want to adjust the color with either true tone on or off you can. Here's how:
Click on settings.
Find General and click on it.
From there, find Accessibility and click on it.
Find Display Accommodations and click on it.
Find Color Filters and click on it.
You should see an image with colored pencils.
Click the toggle to the right of Color Filters.
Look for Color Tint and click it so it has a check mark.
Two sliders below labeled INTENSITY and HUE can be adjusted to your liking.
You can play with this literally for hours even holding a piece of paper next to your phone to get it as close as you can, etc. Or just adjust it until it doesn't seem so yellow, etc. I've played with it for a while but find that leaving it off just seems to be the best. Everyone's panel is different and is individually calibrated at the factory to have the best results. But there can and will be sample variance and some users are more sensitive than others to this.