Is this amount of internal dust enough to have an effect on photos? It's visible clearly through the aperture from both sides of the lens. : r/AskPhotography
A Guide to Cleaning Lenses and Camera Sensors
How to Clean Your Lenses – Lens Cleaning Tutorial - LEICA REVIEW
VisibleDust Lens Clean (30 ml) | bol.com
Amazon.com: Visible Dust VDust Plus Formula Sensor Cleaning Solution, 8ml : Electronics