Video Gamma explained | 4K

Why your screen needs Gamma 2.2

Instagram: chris_dobey

[ArisMelachroinos]

1:45
You say that when the actual light is 50%, we see 25%.
However, looking at your diagram, it looks like when the actual light is 50%, we see 75%...

[testpattern]

Gamma became a concern in the early days of video (1940's) because of the non-linear characteristics of CRT displays. That is called the EOTF (electro-optical transfer function). To compensate, the OETF (opto-electronic transfer function) is applied to the camera output. Add the two transfer functions together and it's linear as your graph shows.

CRT's are now obsolete. You could use linear transfer functions (EOTF and OETF) and achieve the same effect optically, but gamma 2.2 is written into the specs as a holdover from CRT technology.

[karacric]

Your graph is correct, but you read it wrong. Like @ArisMelachroinos said, up to and including actual brightness to 50%, we see INCREASED brightness up to 75% (according to your diagram). THAT's what allows us to see low brightness content. Once things start going much brighter, our eyes start compensating for it and increase perceived brightness by smaller and smaller increments.

[JuraIbis]

Finally a good explanation! Where have you been all my life!

[terrrorizer]

What about hdr content ? Cant seem to change the gamma on my tv wich is set to 1 " 0 being 2.2" so 1 would be 2.4 ? Im trying to calibrate and im having a hard time understanding .

[sisco]

so gamma 2.2 is the best collaboration

[orlevene]

wow! now i can get a sense of how to use it, thanks 😊

[Tottorul]

If the camera captures the light aa it actually is. Then why is the brightness of the straight line percieved as washes out if it represents the brightness it captured?

[AnnoyD]

I'm picking up what you're putting down but you really gotta work on your graph making. Actually would have been easier to understand if there wasn't any visual aid.

[mimo-dy]

Gamma 2.2 or any other values is not perfect because we watching content not in perfect lighting ambient. I Am 100% sure gamma 2.2 is not a good choice for dark room. Many devices such as phones does not have gamma option. Sucks.

[Hades_stz]

How can I convert Linear gamma to ST2084??