I gave my A560 to my brother. He is very happy about except one annoying problem. It looks like there is a dust on the screen, it is about the size of a period in the middle.
He tried to clean it, but no use, including the help from the professional camera cleaner. But it only shows when he uses Contax Zeiss 135mm with adapter. Yes, the lens and the adapter are clean.
I suspect it is a dead pixel, which only shows up when, somehow, the lens causes the disfunction of the dead pixel removal capability. Due yo the distance, I can't take a look in person.
I found some web posts about Sony's dead pixel report. In fact, it seems there are a lot more complaints on dead pixel from Sony camera than other brands, including Nikon, which I believe are supplied from Sony. The reports suggests to redo black neutral calibration, or make it a habit, do it frequently.
Some reports hint that the dead pixel removal routine may actually create more dead pixel, something like the false error propagation in the error correction code when there is false correction.
Anyone with more experience on the dead pixel? Any suggestion?