The Blackmagic Production Camera 4K supports 6G-SDI, outputting uncompressed 10-bit 4:2:2 video, so it can be used to connect to any SDI monitor as well as 4K switchers such as ATEM Production Studio 4K.
SDI is inherently backwards compatible, so even though the camera has a 6G-SDI output, it should work fine with any HD-SDI input device.
If you have the SDI Output set to HD, and have selected to record in 25 or 29.97 fps with the SDI overlays to Off, the SDI output will be set to 1080i50 and 1080i59.94 respectively.