็ป„ๅˆ้€้•œ็„ฆ่ท่ฎก็ฎ—ๅ™จ

1/F = 1/fโ‚ + 1/fโ‚‚

ๅฏ†ๆŽฅๅŒ้€้•œ็š„็ญ‰ๆ•ˆ็„ฆ่ทใ€‚

๐Ÿ“Œ ่ฎก็ฎ—่ฏดๆ˜Ž
  • 1/F = 1/fโ‚ + 1/fโ‚‚ใ€‚
  • 0.1 ไธŽ 0.2 ็ป„ๅˆ โ†’ 0.0667 mใ€‚