Going this route might make the most sense if you already own a DSLR or DSLM (mirrorless) and want to use your lenses from that. Assuming you already have those lenses, this will be the cheapest option of the three discussed in this guide.
There aren't very many lens adapters that let you put a lens from an interchangeable-lens camera on a C or CS-mount body, so you may not be able to find one that fits your lens mount.
One thing to consider when using lenses intended for APS-C or full-frame cameras on a sensor as small as the one on the Pi HQ camera is the crop factor. As discussed previously, the Raspberry Pi HQ Camera has a crop factor of 5.5. This means that if you were to use a 50mm prime lens, the effective focal length would be 275mm, turning a lens that would be a neutral lens on a full-frame camera into a telephoto.
Another thing to consider is weight; having a lens that weighs 10X what the rest of the camera weighs can be a bit unwieldy at times. For heavier lenses, you need to make sure the weight of the lens is going to the 1/4" 20 tripod adapter on the base of the camera and not the PCB itself.
Make sure that either your lens or the lens adapter has an aperture adjustment ring. The one I purchased did not, and I only own one F-mount lens with a manual aperture ring.