04-23-2015, 06:44 PM
JoJu,
"Precision GMo" aka moulded aspheres are certainly possible, but they staunchly limit the number of glasses which can be chosen to about 6 or so, out of ~100 different options otherwise. They are also insuitlble for large departures from the base curvature. Perhaps in the middle there are some meniscus lenses which are easily bent and are made out of Gmo aspheres, but a double-sided asphere which is made via a more normal grind and polish technique is expensive because it is easy to ruin one surface in the process of making the other.
QED MRF machines (https://www.qedmrf.com/polishing-fix/mrf-technology) have the best surface finishing available today but OptiPro's CNC polishers <a>(http://www.optipro.com/pdf/OptiPro_Finis...pdf)</a> aren't too far behind ( a factor of 3 or so, but the difference is just a couple of nm rms) and are capable of bigger departures (MRF is too, but it would take literally days).
An MRF machine is about $2m USD for a small one e.g the Q22-XE I work with and 1L of the fluid used in polishing ranges from about $3000 to $50000 depending on the grade of slurry you use. A liter will last a month or so in the machine before it "dies" and must be disposed of. Other than the slurry the machine just requires DI water, careful operators, and pressurized air/electricity to run so running costs aren't too too high. The OptiPro machines use more standard cerium oxide solutions as opposed to an MR fluid (https://en.wikipedia.org/wiki/Magnetorheological_fluid) so their slurries are cheaper - I forget the price at the moment but it is fairly small. They have vastly higher waste production though, since the fluid isn't recycled as effectively where an MRF machine only loses an ounce or less of fluid every time it is shut down or started up.
Gmo aspheres are also possible, but the engineers like Zeiss really do not like to place many material restrictions on themselves, so I doubt it.
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Brightcolors,
Zeiss doesn't have inflated prices. They have inflated engineering, sort of like BMW. This raises the price, and once the lens moves from "must cost $500" to "must cost $800" they move it up closer to $1200 to price it into a better market for their image.
The elements for the 11-24, aspheres aside, are less than $200 finished product for a normal photographic surface quality. If you move into precision, research, or high energy laser grade surface quality the cost moves up exponentially. The primary and field mirror in a Schmidt telescope I am building were each about $1500 for a 6" diameter flat and spherical mirror respectively because of the fine surface finish.
"Precision GMo" aka moulded aspheres are certainly possible, but they staunchly limit the number of glasses which can be chosen to about 6 or so, out of ~100 different options otherwise. They are also insuitlble for large departures from the base curvature. Perhaps in the middle there are some meniscus lenses which are easily bent and are made out of Gmo aspheres, but a double-sided asphere which is made via a more normal grind and polish technique is expensive because it is easy to ruin one surface in the process of making the other.
QED MRF machines (https://www.qedmrf.com/polishing-fix/mrf-technology) have the best surface finishing available today but OptiPro's CNC polishers <a>(http://www.optipro.com/pdf/OptiPro_Finis...pdf)</a> aren't too far behind ( a factor of 3 or so, but the difference is just a couple of nm rms) and are capable of bigger departures (MRF is too, but it would take literally days).
An MRF machine is about $2m USD for a small one e.g the Q22-XE I work with and 1L of the fluid used in polishing ranges from about $3000 to $50000 depending on the grade of slurry you use. A liter will last a month or so in the machine before it "dies" and must be disposed of. Other than the slurry the machine just requires DI water, careful operators, and pressurized air/electricity to run so running costs aren't too too high. The OptiPro machines use more standard cerium oxide solutions as opposed to an MR fluid (https://en.wikipedia.org/wiki/Magnetorheological_fluid) so their slurries are cheaper - I forget the price at the moment but it is fairly small. They have vastly higher waste production though, since the fluid isn't recycled as effectively where an MRF machine only loses an ounce or less of fluid every time it is shut down or started up.
Gmo aspheres are also possible, but the engineers like Zeiss really do not like to place many material restrictions on themselves, so I doubt it.
----
Brightcolors,
Zeiss doesn't have inflated prices. They have inflated engineering, sort of like BMW. This raises the price, and once the lens moves from "must cost $500" to "must cost $800" they move it up closer to $1200 to price it into a better market for their image.
The elements for the 11-24, aspheres aside, are less than $200 finished product for a normal photographic surface quality. If you move into precision, research, or high energy laser grade surface quality the cost moves up exponentially. The primary and field mirror in a Schmidt telescope I am building were each about $1500 for a 6" diameter flat and spherical mirror respectively because of the fine surface finish.