Imgburn makes the image on-the-fly. You don't need to make a iso to burn.
Imgburn -> mode -> build. Select the drive with the media. As an option select advanced input to create folders, rename files etc.
Prefer UDF 1.02 to maximum compatibility with data disks without the 4GB per file limit of ISO9660/JOLIET.
BD video disks must be build with UDF 2.5.