The WIA Automation Library provides end-to-end image acquisition capabilities to automation-enabled application development environments and programming languages such as Microsoft Visual Basic 6. But after 2 pages i gave up. Because it wasn't really understandable for me. But looks like i have to try it again.. But if I understand this correctly, the application streams nonstop? And I can take a Picture of this "stream"?
Use your DSLR as a high quality webcam and record time-lapse with it at the same time
c# - Controlling a Camera with WIA - Stack Overflow
Photoshop Acquiring digital images from cameras You can copy images to your computer by connecting your camera or a media card reader to your computer. If your camera or the card reader appears as a drive on your computer, copy images directly to your hard disk or into Adobe Bridge. For more information on using Windows Image Acquisition or Image Capture, see your computer documentation. When you use WIA, Photoshop works with Windows and your digital camera or scanner software to import images directly into Photoshop. Select a destination in which to save your image files on your computer.