Ok guys,
state the surface powers required to produce the following lenses with +5.75D front curves.
a) -0.50DS
b) +0.50DS
c) +1.75DS
d) -1.25DS
i'm not sure if it's as straight forward as calculating the difference, eg. a) +5.75 - -0.50 = +6.25.
Any help is seriously appreciated!
To determine the surface powers required to produce lenses with +5.75D front curves, you need to consider a concept known as the lens equation. The lens equation states that the power of a lens is the sum of the powers of its surfaces. In mathematical terms:
Lens power = Surface power 1 + Surface power 2
Now, let's calculate the surface powers required for each lens:
a) For -0.50DS lens, the lens power is +5.75D. Since we have the front curve power (+5.75D), and we need to find the surface power of the second surface, we can rearrange the lens equation as follows:
Lens power = Surface power 1 + Surface power 2
+5.75D = Surface power 1 + Surface power 2
We know that Surface power 1 is -0.50DS, so substituting it into the equation:
+5.75D = -0.50DS + Surface power 2
Rearranging the equation, we get:
Surface power 2 = +5.75D - (-0.50DS)
Surface power 2 = +5.75D + 0.50D
Surface power 2 = +6.25D
Therefore, the surface power required for lens (a) is +6.25D.
You can similarly follow this process to determine the surface powers for lenses (b), (c), and (d):
b) +0.50DS lens:
Surface power 2 = +5.75D - (+0.50DS)
Surface power 2 = +5.75D - 0.50D
Surface power 2 = +5.25D
c) +1.75DS lens:
Surface power 2 = +5.75D - (+1.75DS)
Surface power 2 = +5.75D - 1.75D
Surface power 2 = +4.00D
d) -1.25DS lens:
Surface power 2 = +5.75D - (-1.25DS)
Surface power 2 = +5.75D + 1.25D
Surface power 2 = +7.00D
So, the surface powers required for lenses (a), (b), (c), and (d) are +6.25D, +5.25D, +4.00D, and +7.00D, respectively.