Bob Andersson wrote:
Hi sdowden,
It sounds as though your camera is producing worse results than other users expect at ISO 400. I think a couple of 100% crops would be useful as that may allow those that also have the same model to reach a conclusion about whether your camera is faulty.
I'd also suggest sharing your camera defaults (NR, sharpness etc) and also your post-processing defaults (software used and, again, NR, sharpness etc). Extra work, I know, but I think the community would like to help but it's difficult without more information.

Bob.
P.S. Without getting too far off-topic can you share why it's a good idea to over-expose at ISO 400 when, presumably, the same exposure time at a lower ISO would reduce the risk of blown highlights and, I assume, also potentially reduce the high ISO noise in the shadow areas? I'm just a happy snapper at heart so I genuinely don't understand why, as a matter of habit, one should over-expose at any ISO.

Firstly here is an example
cropped
http://dowdenphotography.com/002.jpg
A4 Size
http://dowdenphotography.com/003.jpg
* both images are at 360DPI for printing.
This is the master exported as a JPEG
http://dowdenphotography.com/004.jpg
I've used just about every setting you can think of, but these were taken like most of my photos these days on abode RGB style, 0 changes, NR on, manual exp. (anyone who shoots in anything else at uni gets in trouble), for post processing I use Aperture then export into photoshop where my girlfriend helps me out with the major editing in some cases.
Sometimes I will use sharpen & NR plug ins in aperture or photoshop when needed.
Its been a issues since I first bumped the ISO up to 400 more than a year ago.
BTW thanks all for the help, fixing it would help me out more than any of you know.