Reddit reviews OwnMy Crystal Ball Photography Healing Meditation Ball Glass Sphere Display with Stand (100mm/3.94")
We found 1 Reddit comments about OwnMy Crystal Ball Photography Healing Meditation Ball Glass Sphere Display with Stand (100mm/3.94"). Here are the top ones, ranked by their Reddit score.
Diameter of Crystal Ball: 100mm / 3.94"; flawless quality, no bubbles/scratches/blemishesIdea for photography: effects like a fish eye lens, got some great shots from itIdea for display: this classic clear crystal ball will add a touch of elegance to any room, perfect place in your office,living room or bedroomIdeal prop for a costume or Jareth cosplay, great contact juggling ballIncluding wooden stand, come in protective packaging; nice gift for who are taking off with photography.
Here you go. The Coma, Chromatic Aberration, Astigmatism, and Spherical Aberration are going to suck, but it truly is a 50mm ƒ0.5 lens (Going by the lens makers equation. In practice, you aren't quite going to get ƒ0.5.)
ƒ0.5 is the absolute maximum aperture possible for a glass lens, and the linked item is the only lens design that can produce such an aperture. But it's possible to build bigger aperture lenses if we use materials other than glass.
The absolute best optical lens possible would be made from crystalized silicon carbide (AKA Moissanite; fake diamond my ass.) A sphere of that stuff would have a ƒ-Ratio of ƒ0.15. That means, we might be able to create a ƒ0.5 lens from that stuff which has a chance of being corrected for aberrations (and distortion)
Moissanite is available in cylinders large enough to grind into lenses. The raw material cost is about $1000 or so for a suitable piece, and I have no idea what the grinding costs or practical considerations would be.
I'm super interested in the subject, but there's not a lot of info out there, and I don't really have the cash to throw at experiments on the matter.