What magnification is the equivalent of 5 diopters?

• A. 50×
• B. 5×
• C. 500×
• D. 0.5×

Answer: (A)

Magnification and diopters measure two different things: how large an image appears versus how strongly a lens bends light. For a simple magnifier used at the near point, angular magnification roughly follows the near-point rule: M ≈ distance to near point / focal length. With the near point about 25 cm (0.25 m) and f = 1/D (in meters), that becomes M ≈ 0.25 / f = 0.25 × D. So with a 5 diopter lens, the approximate magnification is M ≈ 0.25 × 5 = 1.25×, not 50×.

The 50× figure would require a very different setup or an additional magnification system beyond a single simple lens (for example, combining lenses or using a device designed to deliver high overall magnification). In standard lens physics, 5 diopters does not equate to 50× magnification.