Q: Im a photographer, ACD and rMBP ?

If you use the correct adapter

<http://store.apple.com/us/product/MB571Z/A/mini-displayport-to-dual-link-dvi-ada pter>

the display will run at full resolution.  Don't use mirroring (Arrangement tab of Displays system preference).

This is what I use and much cheaper ($29.00) with a late 2012 Macbook Pro (non-retina) and 23" ACD, that's unless you need dual monitors.  Not sure how or if would work with the 30" ACD

http://store.apple.com/us/product/MB570Z/B/mini-displayport-to-dvi-adaptor

The $29 adapter is single-link DVI, so is limited to 1920 x 1200.  The 30" display is 2560 x 1600, so needs the more expensive dual-link adapter.  (Dual-link is for a single display.  It has nothing to do with dual displays.)

Malcolm J. Rayfield wrote:

 

The $29 adapter is single-link DVI, so is limited to 1920 x 1200.  The 30" display is 2560 x 1600, so needs the more expensive dual-link adapter.  (Dual-link is for a single display.  It has nothing to do with dual displays.)

I hear ya.....so the dual-link meaning is Display and USB.  At first I didn't realize the single DVI would only do 1920 X 1200 but that is exactly what the specification say.  Thanks for the heads-up.