Noisy bias frames...?

[Hallingskies]

This is a master bias frame made from 50 exposures, sigma stacked, from my SX-694.  With the dead column and diagonal banding, it seems a lot less smooth than the bias frames from my Atik 460.   It doesn't seem to give a problem in the final image but I just wondered if the SX is firing on all cylinders...? 

Any opinions, anyone?

[wxsatuser]

I would have thought that diagonal pattern is not right.

The column not a problem as such.

[Hallingskies]

Thanks for the reply.  I wondered if the diagonals were a usb issue but it seems the same on several different laptops.

[Martin Meredith]

I always see a diagonal pattern in my master bias frames (also from a SX camera, the Lodestar X2 mono ). This is heavily stretched of course (min val ~ 1.6% of 16-bit range, max val ~ 1.7%). This is a mean stack of 23 frames but I see the same with longer stacks. I've been regarding it as normal...

Martin