X-ray photography magnification is numerically equal to

X-ray photography magnification is numerically equal to the ratio of focal distance to focal limb distance. The ratio of the size (or length) of the photo image to the actual size (or length) of the subject is the magnification.

In macro photography, there is a term that must be understood, and that is magnification. Because macro photography is actually like magnification photography, the magnification directly affects the effect of macro photography. Because the magnification is defined by the ratio of the image obtained on the surface of the negative (or photosensitive element) to the size of the real object, the magnification is expressed as the ratio. Therefore, the magnification is also called "image ratio".

It is often heard that the lens can take macro effects of 1: 1 and 1:2, and these ratios refer to the maximum magnification of the lens. The value on the left represents the size of the image on the negative, while the value on the right represents the size of the actual subject. When the lens can reach the magnification of 1: 1, the lens can completely project the real size of the subject onto the substrate (or photosensitive element).