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p.1 #5 · p.1 #5 · When does Zeiss see it fit to use anomalous partial dispersion glass? | |
Rodluvan wrote:
...the slight difference in lens design and FL introduce fundamentally more aberrations in the 2/35 that forces them to compensate using such glass?
I would say "different" rather than "more." As you note, aside from the 2nd element in the 35/2 replacing the 2nd and 3rd elements in the 28/2, the basic layout appears to be much the same. The rest of the elements have visibly different curvatures, however, and we don't know what kinds of glass they're made of. Likely, the stronger refraction of the wider lens meant that spherical aberrations, distortion, or field curvature were a larger concern than with chromatic aberration in the 35/2. The MTF curves suggest that the 28/2 has more field curvature as it is, and it has a mild moustache distortion whereas the 35/2 is relatively linear.
At any rate, Zeiss decided that the APD element was optimal in the 35 and not in the 28. I'd hardly say that the 28/2 is less lavish, as it costs more than the 35/2--which may be entirely due to the mechanical complexity of mounting the second and third elements properly, whereas the 35/2 only mounts one element in their stead.
Cheers,
Jon
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