It is learned, actually 70% or more off what you see is learned or a better word for it imagined.
The brain is incapable in processing all the information off what your eyes see so the brain make logical assumptions for what's normal so it's almost certain we all see something differently.

Does this answer your question?
I think not but it sounded interesting to write it down. ^^

Thank you Thoramy.

I know it was indeed a tongue cheeck comment but I found it an interesting question so therefore the test.

It seems most of the members don't have a problem.

Your welcome, it was indeed an interesting test.
I know for myself that shades of green are slightly different between my eyes.

Yes and no, this from the site with the tests.

Color blindness can also be caused by accidents and other head trauma where permanent damage to the eyes occurs. This can happen as a baby (Shaken Baby Syndrome), or also later in life. UV Rays also present a risk of becoming color blind; they are in fact the leading cause of normal eye blindness in the world.

The 3rd way to get color blindness is through other hereditary diseases such as Diabetes.

But those are internet users but Thomary specially asked for photographers

Why did Pentax and most other brands hold their 135format mount for the digital aps-c sensor?

Since everything is smaller they could easily make the register distance smaller so that faster lenses are easier to make and the camera is smaller.
Since the lenses specially make for APS-C cameras won't work on 135 format anyway why didn't they make the jump?
If you still want to use 135format lenses you should easily be able to extend the mount to the correct register distance.

From all the brands only Minolta made a special mount for APS I believe.
They call it the V-mount and the Vectis S series cameras used it.

Does someone know a good reason or have insight into this?

If somebody sends you a PM (Personal Messages or something like that) they can still edit it before you read it.

Since you can't delete a PM you could send one and change your mind so the only thing you can do is delete the contents.
The receiver then gets an empty PM.

Welkom terug Lidy, was wondering what happened to you but it's good to have you back.

Thomary asked this question: "How many visually impared photographers do you know?"
So I thought lets find out.

Here are two tests.
colour arrangement test
ishihara colour test

Note: since you're doing the test on a monitor results might not be true.

ps. with other I mean other colour problems.

Yes under presets in the left window under the little preview image in the develop tab.
You can also very fast make your own presets if you want.

Yes sorry, it's so hard to keep up with the versions of Sigma lenses.

Nope, HSM or SDM is only support with the new DSLR cameras.
You need to have the non HSM version do you want to have autofocus.