Good to have a photoclub, for I had not been paying attention to the Sony website lately: a new version of the firmware for the A700 was published already in September! Version 4 is meant to tackle my main issue with the A700: noise in high sensitivity settings. Or more completely (from Sony Europe):
* The choice to select auto exposure bracketing (single & continuous) with 3 shots in 2 EV steps has been added. [That is nice for HDR pictures! I'd like to start that discipline once.]
* The choice to turn [Off] the High ISO NR feature has been added. [Great! I want to be in control.]
* Improvement of the image quality in high ISO setting. [This is the main improvement for me]
* Improvement of the auto white balance and D-Range Optimizer performance. [One of my reasons for always shooting RAW is that the auto-white was not always to be trusted. I'll keep shooting RAW, though. I don't use the D-range optimiser; also a matter of wanting to control things myself.]
* Improvement of reliability for communication between camera body and vertical grip. [Don't have that thing.]
Of course I immediately made a quick try of higher ISO settings. My impression is that ISO 1600 is as good now as ISO 800 was: quite usable. There is a visible reduction in quality from ISO 1600 to 3200. See first set of compared photos. This (out-of-focus) detail from the top-left corner of a picture shows this effect.
The settings of the noise reduction do make a difference. My impression is that setting the noise reduction to 'high' is a big improvement for larger areas, but may make edges and shadows a bit too 'rough'. Look at the left side of the picture frame in the comparison of two photos below.
Thanks to Dieter for telling me about the firmware update!