A major limitation of photography is that the depth of field decreases as the magnification increases. This means that the closer we get to a subject the smaller the depth of field and the smaller the amount of the subject that is in focus. The image below shows the limitation of depth of field in this case the inside of the barrel of a gun to show rifling.

In the 1960s and 1970s a technique called Light Scanning Photomacrography was used to create images but the technique was slow and fiddly and required a very narrow slit of light to be carefully focussed onto the subject as the subject was moved by a linear actuator through the beam of light. Now with computer programmes a whole series of photographs can be taken individually each with a small part of focus and these can be assembled into a completely in focus image. This together with stitching of images takes the camera beyond the conventional optical effects seen with a single photograph. So in the future when looking at a single photograph we may be looking at 5, 10, 30 or even 100s of photographs combined to make the final image.