Why is the camera lens round and the photos rectangular?

Who says that the aperture must be circular? In fact, some photographers will create some special shapes, such as star-shaped masks, and cover them in front of the lens, which will produce a star-shaped light cloud background; circular ones must A circular light cloud emerges. Because the circle is the most accepted shape, the aperture should be made as round as possible. Photos are made into a rectangular shape because humans use their eyes to see horizontally. Therefore, when analyzing images in the brain, the horizontal field of view is wider and the upper and lower fields of view are narrower. Therefore, it is more natural and comfortable to view rectangular photos placed horizontally. Moreover, the rectangular shape is also convenient for paper cutting; the round shape, like the square shape, does not look natural, so it is not advisable. 2010-05-24 10:12:46 Supplement: What you mean is that the lens is round. How to square the circle is actually very simple. As long as the circular image projection of the lens is larger than the area of ??the rectangle, it can cover the entire rectangular area. Can. Of course, the circular projected image of the lens will disappear outside the rectangular position, but what does it matter? Of course, your target will not be these places. The lens glass must be polished in a circular shape, because the plane is composed of 2D, and the lens curved surface will affect the refraction of light. That is, the top and bottom, left and right are all composed of a curvature, so it must be polished in a circular shape. ; Glass must also be round. This can be seen in the manufacturing of eyeglass lenses. The raw material of the lenses is round. After the customer selects the frame, the lenses are polished to fit the shape.

although the lens is circle

but the cmos/ccd is rectangular the circle is bigger than the rectangular so the picture is circle.

Reference: myself

The aperture is based on projection, as if the pistol is completely clicked, and there is a lens inside to take the light downward, as if scanning

And the photo is from the negative ~ If you want the photo to be round

Let’s try using a round mirror to shine light downward

The round photo may look weird~ You also need to learn the basic knowledge of microscopes

Write the word "F" Put the paper on the microscope

See the difference in the direction of the paper?.