"Focus the lens" refers to the process of adjusting the optical elements of a camera or other optical instrument to achieve clarity and sharpness in the image being captured. Some synonyms of this term include "adjust the focus," "sharpen the focus," "fine-tune the focus," "refocus," and "aim the lens." Other phrases such as "set the focus," "lock the focus," or "achieve focus" can also be used. Depending on the context, these synonyms can be used interchangeably to convey the same idea of aligning the optics for optimal image quality, whether it's for photography, microscopy, or other scientific applications.