inertiat wrote:
1) Is the picture just a mirror image? If so, what impact does the difference in aspect ratio have? Does it just stretch things out to the size of the monitor or does it use the monitor's full resolution as well as size?- this applies to the following question also.
It's your choice. You have the option of "mirror" or "extended desktop." Extended means you add space to your desktop and can put other windows and applications on the second monitor. Or put your main window on one monitor and palettes on the other.
2) Can you use the display as an extension to the workspace on the laptop? If so can you set up which side the external display is on? Can you switch between mirror and extension?
Like mirror/extended, this is configured in your Displays preference. There is a proxy that detects all connected monitors and you drag the little icons around to tell the Mac which monitor is on which side. If you have configured multiple monitors on any Mac desktop or laptop in the last 20 years, it still works the same way as you remember. I noticed on Windows XP that external display control panel works similarly to the way the Mac has always worked.
In extended mode, as long as OS X supports the native resolution of a connected monitor, it will display at full resolution with no scaling or stretching. With common monitors, all of them should display at native resolution. If OS X does not support the exact resolution and you choose the closest one, it may stretch. On TVs, you may have to turn Overscan on or off.
It's more complicated with mirroring. If you mirror two displays with different resolutions, OS X must apply the lower resolution to both monitors. The monitor with the higher resolution will have empty black space around the image. This is because you can't make a monitor display higher than its native resolution, and mirroring requires the exact same size image, so it has to take the lowes resolution of all connected monitors and apply to them all.
You can do some quick switches using the Displays icon in the menu bar. From there you can set resolutions, switch extended/mirroring directly, without going into System Preferences.
3) Can you close the Macbook and carry on working on the external display? If so how does the change-over occur - i.e do all your windows stay with the book or do they all move over to the external? And what about mouse and keyboard?
Read this
http://support.apple.com/kb/HT3131
Any time you remove a monitor, OS X will collect all open windows to the remaining monitors. When you close the lid, you are removing the internal monitor from use because there's no point in displaying on a closed lid.
The mouse and keyboard automatically map their coverage area to however many monitors you currently have connected. You can play with this by connecting/disconnecting displays while the computer is running. You'll watch everything change on the fly.
4) On a similar note and with the above questions in mind, can you really connect the Macbook Pro to the new 21.5" iMacs?
Supposedly through the DisplayPort input on the 27" iMac, but I don't own either of those machines.