Which factor does not usually require adjustment when switching body habitus in radiography?

When switching body habitus in radiography, the source-to-image distance (SID) usually does not require adjustment. This is because the SID is primarily determined by the setup of the imaging equipment and the specific radiographic procedure being performed, rather than by the physical characteristics of the patient.

In practice, while other factors like kilovoltage peak (kVp), milliamperage (mA), and exposure time are often adjusted to compensate for differences in body habitus and radiation absorption, the SID remains consistent to ensure the proper magnification and image quality are maintained. Adjusting kVp can help penetrate denser tissues in larger patients, while mA and exposure time might be modified to ensure adequate image density and clarity based on the thickness of the area being imaged. Therefore, SID is a stable factor that does not typically change when adapting to different body shapes or sizes.