Was wondering what the difference between the 840k and 900nc when imaging besides that the 900nc has more frame rates (90 frames/s)??
I also heard the 900nc is 50% more sensitive than the 840k? is that true?
maybe for webcamming, but for astro, i would rate the 900nc as 5-10% better, but 20% dearer.
there is a yuy2 codec which does not compress the data as much, but that codec can actually be loaded into the 840k.
the 840k has a nicer backend ie numbers for the sliders ie 10%, 20%, the 900nc does not.
Raw macros ie to get uncompressed avi's out of a toucam at 5fps work for the 840k, but not the 900nc, unless you have installed the drivers for a 840k before hand. This is currently being fixed by Martin Burri et al, but will be a while.
Look both are superb bits of astro gear and to be honest, save yourself $40 and go the 840k whilst you can. The 900nc is a fine replacement for the 840k, but not a huge jump in technology to warrant only buying 900nc.
If they were the same price, then the 900nc would be preferable!