Convex lens: radius of curvature (R)
We should all know what a radius of a sphere is, so it should be easy to remember that:
The "radius of curvature" of a convex lens is the distance between the centre of curvature (C) and the curvature of that sphere.
There are two radius of curvatures for a convex lens, as below:
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-log-table-1.4df6ee6.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-log-table-2.d516bb3.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-1.b0b0513.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-2.f89189d.jpg)