Chosen Solution
When the lance is pointed at a light area a black spot is visible. it shows up on most of true pictures taken.
This is probably due to a piece of dust on the IR filter inside. There’s an excellent video on youtube (https://www.youtube.com/watch?v=0nmwt0fr…) by Graham Houghton which shows how to remove it. I did this three times on a TZ-10 with 100% success and 0% damages. Since the dust is not on the sensor, but 2 mm away on the filter, a closed iris and a light detail free picture (like cloudless sky) is the best way to watch these spots. Another hint: The spot will not move with various focal lengths (zoom), but you’ll see it moving when the cam switches from optical to electronical zoom (if enabled).
