What aperture do you use?

.6) to capture a shallow depth of field, so the background behind the subject is nicely blurred, making them stand out more.

Is F8 the best aperture?

F8 Is an OK default aperture, which gives you enough depth of field to make everything clearly visible.this is ideal aperture Use when you use a manual focus camera (area focus, film or digital Leica/rangefinder or any other manual lens).

Where is my lens sharpest?

For a lens with a maximum aperture of f/3.5, the sweet spot for the lens is somewhere between f/8 and f/11. Likewise, if your lens has a maximum aperture of f/1.4, the sweet spot for the lens is between f/2.8 and f/4. This simple rule of thumb applies to most lenses you will have.