Convert settings to another model (PowerShot S120 -> G7X Mark II) - convert ISO to f stop?

[NeverEdit]

Hello, on my PowerShot S120 I had my favorite settings for a certain situation saved on C, the settings were:

Manual Mode - 1/200 - f 7.1 - ISO 80

I now have the G7X Mark II but this camera's lowest ISO is 125 (@canon: please bring back ISO 80 in future models), so I tranferred the settings to:

Manual Mode - 1/200 - f 7.1 - ISO 125

I realize that from ISO 80 to ISO 125, there is an increase of brightness by 56% -

here are my questions:

1. so to get the same effect, do I need to increase shutter speed by 56% (like 1/320), or increase f stop by 56% (like f 11), or 26% for each value?

2. Or can I achieve the same effect by exposure compensation?

Question with this is, a) is that possible in manual mode, and b) is this saved with the C settings, regardless of the position of the button on the camera?

3. Or Is there a way to convert ISO to f stops, like xx ISO equals yy f stops?

4. The other difference is of course that the S120 has 1.17" sensor size and the G7X has 1" sensor size, does that affect the above calculation, and if so, how?

Lots of question, I hope I can get some answers... Thank you!

[TTMartin]

Your C settings are saved based on their mode you are in when you save them.

If you want your C setting to be Av, set your camera to Av, apply all the settings you want then save it to a C setting.

If you want your C setting to be Tv, set your camera to Tv, apply all the settings you want then save it to a C setting.

If you want your C setting to be M, set your camera to M, apply all the settings you want then save it to a C setting.

All of the settings that are in effect on the camera when you save your C setting, will be saved in the C setting, including things like focus mode, auto ISO, etc.

Normally you do not want to be in the C setting when you save the C setting, the exception to this is when you want to 'tweak' your C setting. For example, your C setting is set up just the way you like it, except doesn't have Auto ISO, then you can simply be in the C setting, change the camera to Auto ISO and resave that C setting. All the other settings will be the same as you had stored except now that C setting will have Auto ISO. 

[NeverEdit]

Thank you, yes, I want to "tweak" my C settings so I get the same exposure/effect that they had on the S120, and my question is, if I don't have ISO 80 anymore now, how exactly do I tweak them?