What is the defocus of SLR camera? What is the specific performance of the photos taken? Will Canon 7-2f4 run out of focus without image stabilization?

defocusing means that the autofocus function of the lens is inaccurate, which simply means that the clear part of your photo may be unclear. For example, when you take a portrait and focus on your eyes, the machine also shows that the focus is complete, but the focus of the actual photo is not on your eyes, maybe on your nose, which makes your eyes blurred. Out-of-focus is generally related to the focusing accuracy of the fuselage and the factory adjustment of the lens, which is often different from person to person.

From the above explanation, it can be seen that defocusing and blurring caused by the shaking of the camera body in photography are two different things. For example, in a certain light environment, the shutter speed given by photometry is 1/1s. At this time, the photo will inevitably be blurred because it can't be held firmly, but if there is anti-shake, it is possible to shoot clearly.

This also explains your second question. Whether the lens is out of focus has nothing to do with whether the lens has anti-shake function.

the anti-shake lens can ensure that you can take a clearer picture under a lower shutter, but it depends on luck whether you are out of focus or not.