08-05-2017, 07:36 AM
@Wim - Regarding the "graduated aperture" - is that even possible ?
Diffraction does only occur at the edge of materials that have a different refraction index, doesn't it ?
I have a hard time to believe that the APD element has a variable refraction index.
THAT BEING SAID - when looking at the bokeh highlights - the effect is only extreme (and I mean really extreme) at f/2.8. It is already massively reduced 1/3 stops down. That could indicate that the APD element does indeed consist of two different segments - with the outer ring having a very different refraction index.
Diffraction does only occur at the edge of materials that have a different refraction index, doesn't it ?
I have a hard time to believe that the APD element has a variable refraction index.
THAT BEING SAID - when looking at the bokeh highlights - the effect is only extreme (and I mean really extreme) at f/2.8. It is already massively reduced 1/3 stops down. That could indicate that the APD element does indeed consist of two different segments - with the outer ring having a very different refraction index.