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The one thing I can't find is a description of the actual glass optics used. How many elements? What are their individual specs? Etc. I do some optics design,
by analog31 4y ago
The one thing I can't find is a description of the actual glass optics used. How many elements? What are their individual specs? Etc.
I do some optics design, albeit not photographic lenses. But a f/2.5 lens is not considered to be an easy design problem.
- johnandrews911 4y agoI have to second this, id like to get some more details, this really isnt a trivial task, im curious about the specifics
- namibj 4y agoI assume it's just very narrow FOV and not achromatic.
- dotancohen 4y agoFrom the fine article: > The only parts of the lens that can’t be 3D printed are the > glass optics, and for this Steele used Surplus Shed to > acquire achromatic (two-part) lenses.
- ben_w 4y agoI can’t help but feel that’s no longer "3D print… a… lens". Everything else? Sure, nice job, but not exactly surprising.
- dotancohen 4y agoIn photography, a "lens" generally refers to the mechanical component that houses the optical lens. In 3D printing, "print" generally refers to "most of the device, except those components that one versed in the field would recognized as being composed of materials not suitable for printing". Though I do agree with you, many people who do 3D printing would not find the title misleading.
- kabouseng 4y agoNope, a lens holder is the mechanical component. Most people and people in industry would refer to either the optical element(s) or the complete assembled optic as the lens.
- dotancohen 4y agoI am referring to the complete assembled optic.
- Kye 4y ago>> "In photography, a "lens" generally refers to the mechanical component that houses the optical lens." Where did you hear this? I probably see people use "glass" to refer to lenses as often as I see "lens."
- dotancohen 4y agoTry Google Images: https://www.google.com/search?q=photography+lens https://www.google.com/search?q=photography+lens You'll see not a single glass lens by itself, but rather every image will be of an assembly containing optical lens intended for mounting to a camera. Also, enter any photography store and ask to see the lenses. You'll not be presented with discrete glass, but rather with assemblies containing glass intended for mounting to a camera. Perhaps in the eyeglass industry the term "lens" refers to the glass itself as a discrete component, but not in photography.
- dekhn 4y agoThe issue is that while you can print 3d lenses (fun read: https://formlabs.com/blog/creating-camera-lenses-with-stereolithography/ https://formlabs.com/blog/creating-camera-lenses-with-stereo...), it's just not practical unless you're super into the project (similar for telescope makers who grind their own lenses). The long and short of it is that high quality glass is an industrial process that has hundreds of years of refinement to give you excellent image quality at very low prices. That said, I have cnc'd a piece of acrylic, polished it, then used it to make a silicone mold and used that to make an epoxy lens.
- azalemeth 4y agoThe sample images show significant vignetting and spherical aberration. The focal plane is curved and clearly not flat over the field of view of the image. There is indeed not obvious chromatic aberration, but I suspect that it is because other issues are significant – there is no mention of the lens's MTF/OTF or any significant tests. One of the other commenters has highlighted that the lenses in question are part of this telescope kit – https://www.surplusshed.com/pages/item/T1686.html https://www.surplusshed.com/pages/item/T1686.html – which is indeed consistent with a reasonably good on-axis or paraxial design but with poor off-axis performance (like most telescopes). I presume these are two apochromatic doublets [1] but it's a bit hard to see. [1] https://en.wikipedia.org/wiki/Apochromat https://en.wikipedia.org/wiki/Apochromat
- eternityforest 4y agoI wonder how well software could fix that? Could one of the hack firmwares be modified to correct the lens in camera? Seems like software correction would open a lot of possibilities for DIY lenses.
- Demiurge 4y agoIt’s information completely lost, it can be guessed with DALL-E but I don’t think that’s helpful in lense assessment. The spherical lense creates a sphere of field of focus. The best way to correct for this is to have a spherical sensor. Canon and Sony have indeed been working on curved sensor manufacturing, but it seems like a moonshot.
- jaywalk 4y agoI know next to nothing about how sensors are manufactured, but we do have the technology to build flexible displays. So what are the major challenges in building "flexible" (for lack of a better word, obviously they would be fixed in place) sensors?
- dekhn 4y agoI don't think this is correct. The camera is applying a PSF (point spread function) to the image. If you have a known target image you can find the inverse of the PSF and apply that as a correction (deconvolution).
- hwsmythe 4y agoIt's a 65mm diameter achromat. You can see the details in the article at pixelsandprisms.com
- burlesona 4y ago> The only parts of the lens that can’t be 3D printed are the glass optics, and for this Steele used Surplus Shed to acquire achromatic (two-part) lenses. He says that eBay is another option, but to make this particular lens builders will need one with a diameter of about 65mm. Link points to here: https://www.surplusshed.com https://www.surplusshed.com, perhaps he bought a telescope lens?