02-11-2015, 03:30 PM
The 24L is limited by primarily sagittal oblique spherical. Coma grows by x^2 as you move away from the center so the performance will quickly "disappear" at wide apertures. Coma is typically targeted for correction, often eliminated with an asphere, but sagittal oblique spherical is very difficult to correct.
Samyang's lens is limited primarily by strong spherical aberration and astigmatism. The spherical grows by y^3 as you increase the aperture size so it hampers the performance of their lenses wide-open in the center but they quickly improve. The astigmatism varies by y as you increase aperture and x^2 as you move away from the center so it is harder to correct by stopping down.
Samyang's lens is limited primarily by strong spherical aberration and astigmatism. The spherical grows by y^3 as you increase the aperture size so it hampers the performance of their lenses wide-open in the center but they quickly improve. The astigmatism varies by y as you increase aperture and x^2 as you move away from the center so it is harder to correct by stopping down.