Can I create a closed LAN with my MacBook Wifi acting as an access point?

Sony cameras can tether and transmit photos over Wifi to an FTP server. I was able to create a closed LAN with the Sony camera connected to a wifi router connected to my Macbook ( [https://www.daviddegner.com/blog/the-best-wireless-tether-for-sony-alpha-cameras/](https://www.daviddegner.com/blog/the-best-wireless-tether-for-sony-alpha-cameras/) ). But, can I take out the wifi router and have the camera connect directly to my macbook's wifi without introducing a WAN? The FTP transmission works with "Internet Sharing" turned on sharing the "iPhone USB" connection over Wifi. But conceptually I don't need the iPhone's WAN because the camera connects through the Macbook's wifi directly to an FTP server running on the Macbook. Can I create a network service that fakes a connection to a WAN so that I don't need my iPhone involved?