Your connected camera would need to mount as a drive volume before Photo Mechanic will be able access the images files on the memory card. Our Nikon cameras do not mount as a drive volume on any recent Mac OS. A card reader will let you access the image files on your memory cards. You can use Ingest or the Copy Photos utility to save the images to a local or networked drive.
If you drag the card volume icon from the Desktop to Photo Mechanic's Dock icon, then Photo Mechanic will open a contact sheet tab for each folder of images on the memory card. The Command-t shortcut will select all of the Tagged images in the contact sheet to quickly access the best images in the folder.
Best regards,
--Bob