= BFL)
distance on the optical axis between last active optical surface and the sensor when the object is at infinity.
The value is only valid in paraxial optics, ie for objects close to the optical axis.
Further off the optical axis, the focal distance of distant objects is affected by the spherical aberration.
(back focal distance = Back Focal Length = BFL)
Note:
Not to be confused with the effective focal length EFL!
Barrel Distortion (C) Wikipedia
The difference between the usual color and monochrome – ( ” black and white ” – ) cameras is an additional layer of small color filters , mostly arranged in the so-called ” Bayer pattern ” (patented by Bryce E. Bayer, 1976, employee of Eastman Kodak ) .
See Why can color cameras use lower resolution lenses than monochrome cameras?
Best Form Lenses are specifically designed optical components that aim to minimize spherical aberration while still utilizing spherical surfaces for their construction, rather than aspherical shapes. Here are the key points:
Spherical Surfaces: They maintain spherical geometry, which simplifies manufacturing while still providing effective optical performance.
Performance: These lenses are optimized for collimating and focusing light beams, making them ideal for various applications where precision is crucial.
Aberration Reduction: The design focuses on reducing optical distortions, particularly spherical aberrations, to enhance image quality.
For further details and calculations related to Best Form Lenses:
A picture taken with a monochrome camera usually has 256 levels of gray.
If the image just has two gray levels, it’s called “binary” image.
An old style fax usually shows a binary image