I think there is a speck of dirt but this is not vissible. I have tried to clean with fine brush and blowing into lens. I am reluctant to use high pressure air as may cause more damage. How do I dismantle the lens to clean the cover flaps mechanism? Are special tools required?
You can use a compressed air to blow any debris you will not damage anything. Pull back the lens shutters manually & blow air in behind them. If still stuck contact me & will tell you how to disassemble lens cover so you can thoroughly clean.