Your camera aspect ratio is 1.5:1, if typical FF dSLR (36mm x 24mm or 22.5mm x 15mm). Regardless of what your camera has, the print output sizes after capture have always been to fit the 'canned' paper formats, or a custom crop size (ignoring entirely capture size or output to standardized sizes.
1.25:1 (5 x 4", 10 x8", 20 x 16")
1.27:1 (14 x 11")
1.4:1 (7x5")
1.5:1 (6 x 4", 12 x 8")
And then there are all the film format camera sizes which almost all deviate from the 'standardized' print sizes, too (such as)
1.22:1 (RZ67, 68.4mm x 56mm)
1:1 (Hassy, 56mm x 56mm)
1.29:1 (Bronica 645 55mm x 42.5mm)
Along comes digital printers and then they foist new photo sizes
1.29 (11 x 8.5")
1.44:1 (13 x 9")
And then the new monitor aspect ratios
1.77:1 (16:9(
1.6:1 (16:10)
So all a digital photographer can do is to shoot RAW to capture the full dimensions of the sensor, then use RAW conversion program to output different aspect ratio JPG files which FIT THE PRINT to be ordered