Can someone give me a good explanation of the Seiko 10 mm fitting button when fitting single vision lenses and the need for the OC. Is this JUST a Seiko thing or is there any other hi-index lenses that incorporate this ???
Can someone give me a good explanation of the Seiko 10 mm fitting button when fitting single vision lenses and the need for the OC. Is this JUST a Seiko thing or is there any other hi-index lenses that incorporate this ???
To the best of my knowledge, Seiko is the only manufacturer that advertises a "spherical button." I think this is marketed as a fitting and dispensing feature.
Keep in mind that the asphericity increases gradually from the center of an aspheric surface. Consequently, the central region of most aspheric lens designs is virtually indistinguishable from a sphere out to a reasonable distance, anyway. Forcing the central region to be perfectly spherical, if this is indeed what Seiko does, would probably necessitate some optical compromises in the periphery, or at least within a transition region between the spherical "button" and the periphery of the lens.
Darryl J. Meister, ABOM
I should add that I've never actually analyzed the optics of Seiko's design, so I'll have to leave it to a representative of Seiko to speak to the merits of this approach.
Darryl J. Meister, ABOM
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