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Focal Length Formula:
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Focal length is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimeters (mm). It determines the angle of view (how much of the scene will be captured) and the magnification (how large individual elements will be).
The calculator uses the focal length formula:
Where:
Explanation: The formula calculates the required focal length to achieve a specific field of view with a given sensor size.
Details: Focal length is crucial in photography and videography as it determines how 'zoomed in' your photos appear. Shorter focal lengths give a wider field of view, while longer focal lengths give a narrower field of view.
Tips: Enter the sensor size in millimeters and the desired field of view in degrees. Both values must be positive numbers (sensor size > 0, field of view between 0-180°).
Q1: What's the relationship between focal length and field of view?
A: They are inversely related - longer focal lengths give narrower fields of view, while shorter focal lengths give wider fields of view.
Q2: How do I find my camera's sensor size?
A: Sensor sizes are typically listed in camera specifications. Common full-frame sensors are 36mm wide, APS-C around 22-24mm, and Micro Four Thirds about 17mm.
Q3: Does this work for all lens types?
A: This calculation works for simple lenses. Complex lens designs (like fisheye) may have different field of view characteristics.
Q4: Why does sensor size affect focal length?
A: Smaller sensors 'crop' the image, effectively increasing the apparent focal length compared to full-frame sensors.
Q5: Can I use this for telescope calculations?
A: Yes, the same principles apply to telescopes, though you might need to consider additional factors like eyepiece characteristics.