Hi @BamJam,
The field app on a iPhone or small phone factor device only support portrait mode. On larger tablets landscape is also supported. This will not change in near future as is a limitation of the underlying AppStudio framework and the design of the applications currently.
However, when using the camera in Survey123, it is still possible to capture landscape image. Provided that orientation lock is not enabled on the device, when the phone is turned to landscape, the image will be captured in landscape, and added back to the form preview and stored as a landscape image. The control in the camera will still remain in portrait though.
Regards,
Phil.