dust problem?

[alexfrank]

i'm having a problem with what i think is dust on my sensor. I am new to the digital slr world and have been very happy with the sony alpha i purchased. However within the past say 10 days i have noticed what i think to be dust in the bottom right corner, first off i hope it is dust and not a dead pixel, i know not how to tell the difference, however, the dust is always perfectly in focus no matter what I am focusing on, it is shaped like a quarter circle and is totally black, i have cleaned the lense, and the mirror tediously and have not had any success, i have also used the cleaning processes that my camera comes with the ability to do. I am certain it is not on the lens, and am fairly certain it is not on the mirror inside my camera. My question is how can i tell what it is, and how do i fix it? thank you.

below ive attatched a greatly enlarged picture, thank you again.

Alex Frank

[coldrain]

That is very stuck dust on the sensor (normally dust does not show that clearly). Only dirt on the sensor will show up on pics like this, not dirt on the lens or mirror since those will always be very out of focus.

This is so infocus though, that it is almost as if this dirt is on the sensor itself, not the protective glass covering the actual sensor!

Try cleaning it with special "wet" cleaning kits for the sensor.