[gisolury]

Would I see the black dot on photo inside the lens when I turn to small aperture (e.g. F22). Or should that apply to dust on sensor only, just a reduction of light pass through? Thanks

[GARETH88]

Perhaps some dusts paste on the sensor surface.
If there are dust in the lens you can easily be aware

[wllui]

dust in the front will have less effect than in the rear.

how often you would use aperture at F/22 ? I rarely use smaller than F11