Lens Sign Notation

[DieselPetrolGrl]

Someone
Please correct me:

Lens/Mirrors Sign Notations:

Negative focal length for:
Diverging lenses aka concave lenses
Behave like convex mirrors do

Positive focal length for:
Converging lenses aka convex lenses
Behave like concave mirrors do

For mypopia : use diverging
For farsigtedness use converging

Do we haveto know lens makers eq? Anyone know a sample that it would apply to? ( ~ thanks! ~)

I feel like my whole mental layout of this topic is wrong somewhere ? can anyone find a flaw/ error? Thank you for your time !

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[Reinhard]

Someone
Do we haveto know lens makers eq?

The EK physics book says that they will give you the lensmakers equation on the passage. Whether that's true or not, I am not memorizing that. I am yet to come across any problem that requires that equation.

 

[DieselPetrolGrl]

thanks
still hazy on the notations ..but i am developing a bit of a intuition so i guess thats a bit of a step forwards