Setting up RAID 1 on an existing HDD

My goal here is to set up a RAID 1 (mirroring) on a data (non OS) HDD that already has files on it.

I'm a photographer and have 1000's of images spread across two HDD's that I want to consolidate to one larger HDD on a RAID 1 configuration. My current configuration is this:
250GB SSD for WIN 7 and Photoshop
700GB HDD for programs, files, etc
1TB HDD (243 GB free) for photos
2TB HDD (1TB free) for photos

My plan is to consolidate the 1TB and 2TB to a 4TB HDD and mirror it to another 4TB but I'm not sure of the correct way to go about it.

Can I simply just install the two 4TB and set them up to RAID 1 using WIN 7 (vs motherboard) and then copy my photo file structures onto the new 4TB? If so, can I just drag and drop or should I use a cloning software?

I had read through this forum that it's a little difficult to do this if I was trying to do it with a drive that has the OS on it. But since this is not the case, I was hoping it would be as simple as I mentioned above.

I am also backing everything up to a HP Mediasmart EX490 server every night and a separate 4TB external drive periodically.

Thank You,
Chuck

RAID1 only protects against mechanical problems with one of the drives and any accidental deletes, malware harm, etc. will be immediately cloned to the 2nd drive. If you are aware of these (and since you already have a backup scheme going on), and still want RAID1 (called a mirrored volume in Windows) it is best to create the array when disks are empty. As far as I know, you will have to format them once RAID is set, and I am not aware of any 3rd party tools which can do so without a format.

So, attach both 4TB drives and create a mirrored volume in Disk Management (they will turn to Dynamic disks). Just copy paste as you wish after the format is over.

Also, how you go about if a drive fails - RAID 1 Mirroring with Windows 7 « Buildegg Articles

That's what I thought but just wanted to make sure. Thanks for your help!