巴罗放大计算器
使用此巴罗放大计算器快速获得准确的计算结果。
Effective Focal Length
2,000.00 mm
Effective Focal Length vs Native Focal Length
公式
## Barlow Lens Effect A Barlow lens is a diverging lens placed before the focal plane that increases the effective focal length. ### Formulas **f_eff = f * B** **N_eff = N * B** where B is the Barlow magnification factor (commonly 2x or 3x). This narrows the FOV and increases the image scale, useful for planetary and lunar imaging.
计算示例
1000 mm f/10 scope with a 2x Barlow.
- 01f_eff = 1000 * 2 = 2000 mm
- 02N_eff = 10 * 2 = f/20
常见问题
Does a Barlow reduce image brightness?
Yes. The longer focal ratio means less light per unit area on the sensor, making it slower for extended objects.
When should I use a Barlow?
For high-resolution imaging of planets, the Moon, and double stars, where you need a larger image scale.
Can I stack Barlows?
Technically yes (a 2x and 3x give 6x), but image quality usually suffers. It is better to use a single higher-power Barlow.