Subject Distance Calculator

Calculate how far your subject was from your camera. Perfect for bird and wildlife photographers using telephoto lenses.

📸 How to Use This Calculator
Show Guide
  1. Select Your Camera Body
    Choose your camera from the dropdown list. This automatically fills in the correct sensor height (in mm) and photo vertical pixel count for your camera model.
  2. Measure Your Subject
    Enter the real-world height of your subject (e.g., if photographing a bird that's 16 cm tall, enter "16" and select "cm").
    For the subject height in pixels: Crop your photo to show just the visible top and bottom edge of the subject, then note the pixel height. Most photo editing software shows pixel dimensions.
  3. Enter Lens Details
    Input your focal length in millimeters (e.g., 300mm). If you used a teleconverter, enter the multiplier (1.4× or 2.0×). Otherwise, leave it at 0.
  4. Calculate Distance
    Click "Calculate Distance" to see how far your subject was from your camera in both meters and feet. The result also shows the effective focal length and magnification used.
Formula: s = f × (1 + 1/m) where m = (subject_px / image_px) × sensor_height / real_height
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