Difference between revisions of Optics related math
→The thin lens equation: add a picture |
→From 20/20 prescription: got a bit sloppy with signs |
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| Line 58: | Line 58: | ||
But rather than actually placing such a lens in front of your full prescription, | But rather than actually placing such a lens in front of your full prescription, | ||
simply | simply add that value (being careful with signs). | ||
ie if your screen is 50cm away, that corresponds to a power of <math>\frac{1}{0.5} = 2D</math>. | ie if your screen is 50cm away, that corresponds to a power of <math>\frac{1}{0.5} = 2D</math>. | ||
So that's the value you'd | So that's the value you'd add to your full prescription (resulting in a less-negative lens). | ||
===From blur horizon of naked eye=== | ===From blur horizon of naked eye=== | ||