As our optics expertise and manufacturing experience of optical lens and board camera lens, we collect S-mount M12 lens, M7 lens, and M5 phone lens modules with different focal length, view angle (FOV), and parameters in our online store.
A lens produces images in the form of a circle, called the image circle, also known as an optical format. In a camera module, the imaging element has a rectangular sensor area (the image size) that detects the image produced within the image circle. The ratio of the length of the horizontal to vertical sides of a video image is called the aspect ratio, which is normally 4:3 or 16:9 (H:V).
The lens optical format should match with the target image sensor like the leftmost photo in Figure3. If lens optical format and image size don’t match, it also works. But when the lens optical format is larger than the image sensor, the lens FOV will be reduced; and when the lens optical format is smaller than the image size there will be dark areas around the corners and some portion of the sensor area is not useful.
The FOV is also called the angle of view which is the shooting range that can be viewed by the lens given specified image size. It is usually expressed in degrees. Normally the angle of view is measured assuming a lens is focused at infinity. The angle of view can be calculated if the focal length and image size are known.
First of all, it should be noted that when a lens is shipped from the factory, a "lens inspection projector" is generally used to inspect the resolution of the lens. The resolution index embodied in the lens inspection projector is expressed in lp/mm, that is, the number of line pairs that can be resolved per millimeter (line pair), but generally lens manufacturers do not explicitly mark this index in the specifications, but rather replace it with a more intuitive 1MP, 2MP or 3MP mark.
Regardless of how the lens images, the Pixel Size of the sensor affects the physical limit of its ultimate recognition resolution, which is called the Nyquist Frequency, and the smallest Line Pairs that the camera can resolve will be exactly twice the Pixel Size. However, the Line Pair happens to have Moiré-effects at the Nyquist Frequency, which means that the actual scene cannot be projected exactly on the middle of the Pixel, causing the limit to be sometimes resolved and sometimes not. At 0.66 times the Nyquist limit, the amplitude can remain largely unchanged regardless of the phase. Therefore, empirically we will take 0.66 * Nyquist Frequency as the practical resolution limit, which is equivalent to using 3 pixel sizes for one black and white transformation (Line Pair), so the correction formula is as follows:
Pixel Size = 1/[3*(lp/mm)] Unit:mm
To sum up the above, the lens with Line Pair as the standard can be converted to pixel size, the sensor also uses pixel size as the standard, in the standard above the two can achieve consistency. Therefore, the following criteria are met
To achieve the above two points is the best match. The lens or the sensor is too low or too high is not very suitable, it can be used, but may be limited by a certain party, IADIY will choose the most appropriate match for customers to provide the most suitable products to meet customer needs.