I just got my 2405 and have it working on my Mac (G4, 1.25GHz upgrade to 350 sawtooth, 0S10.3.9 , 1.5 Gs RAM) - Had to upgrade to an ATI radeon 9000 card for FCP5.

It looks great but I noticed a number of set-up parameters are greyed out.

I can't adjust the contrast, only brightness - and it feels too bright to me, I would like to drop the contrast settinga bit.)

Also the sharpness setting looks too high for me especially on text, but all the "Image Settings" on the menu are greyed out including sharpness and phase.

I am using the DVI connector.

What's up?
Anyway i can get control of that stuff.

Also I found it a little hard to use the calibration set-up in my "System Preferences" as it semed to give me a washed out bright image, so I ended up adjusting to eye, but its going to take more work just futsing to satisfy my taste.
On my previous Sony trinitron , the calibration set-up worked fine.