मुफ्त फोकस दूरी कैलकुलेटर
लेंस या दर्पण की फोकस दूरी निकालें। वस्तु और प्रतिबिंब दूरी से फोकस दूरी जानें।
फ़ोकस दूरी
10.00 cm
Focal Length vs Object Distance
सूत्र
Focal Length
The focal length defines the converging or diverging power of a lens or mirror.
Formula
1/f = 1/d_o + 1/d_i
Lens power in diopters is D = 1/f (with f in meters). Positive focal length = converging lens; negative = diverging.
हल किया गया उदाहरण
An object at 30 cm produces an image at 15 cm.
- 011/f = 1/do + 1/di
- 021/f = 1/30 + 1/15
- 031/f = 0.0333 + 0.0667 = 0.1
- 04f = 10 cm
- 05Power = 100/10 = 10 diopters
अक्सर पूछे जाने वाले प्रश्न
What are diopters?
The unit of lens power, equal to 1/f where f is in meters. Eyeglass prescriptions use diopters. Positive = farsighted correction; negative = nearsighted.
How does focal length relate to camera zoom?
Longer focal length gives higher magnification and a narrower field of view (telephoto). Shorter focal length gives a wider field of view (wide-angle).
What determines the focal length of a lens?
The curvature of the lens surfaces and the refractive index of the glass. The lensmaker's equation relates these to focal length.
सीखें