Talk:Aspheric lens

message: Please don't move this page to "Aspherical lens" (which now redirects to this article). The universal term for these in the optics industry is (AFAIK)  "aspheric lens" (or "asphere"). I just did a quick survey of a half dozen major optics vendors. Every single one uses the latter term.--Srleffler 12:54, 6 December 2005 (UTC)
replies: text: Stubs are by definition short. Anything longer than about a screenful of text is not a stub.--Srleffler (talk) 15:32, 13 January 2008 (UTC)
thread_title: Untitled

message: CorvetteZ51 (talk) 12:53, 27 February 2008 (UTC)
replies: text: Powerful words from someone who can't spell.  I'm going to back out your change until you tell us what's behind it. Dicklyon (talk) 16:01, 27 February 2008 (UTC)
replies: text: That may have been too harsh. His edit looks like it was done in good faith to me. Looking at the article, I can see that someone who primarily knows about ophthalmic optics might find it lacking. The section "Non-optical advantages of aspheric eyeglass lenses" is particularly bad, but I don't know enough about it to rewrite it. If CorvetteZ51 does know something about it, he may have a lot to add.--Srleffler (talk) 18:59, 27 February 2008 (UTC)
replies: text: I thought it was harsh of him to call the article complete BS and then add unsupported claims to the lead, with a misspelling of a word that one knowledgeable in this field should be very familiar with.  So I figured it was good to challenge him to fix it. Dicklyon (talk) 02:38, 28 February 2008 (UTC)

text: OK, most of the article is not BS. Eyeglasses only, aspherics offer a reduction in thicknesss of 20% or so, at the expense of increased off-axis astigmatism and different geometric distortion, as compared to a spherical base (front) curve.CorvetteZ51 (talk) 15:34, 28 February 2008 (UTC)
replies: text: Do you know of a reference (print or online) that supports that? I don't doubt your claim, but it's helpful to Wikipedia to be able to back up the information that appears in the articles.--Srleffler (talk) 16:18, 28 February 2008 (UTC)

text: Apology accepted, as Stephen Colbert would say.  So find us a good source and write that up. Dicklyon (talk) 16:16, 28 February 2008 (UTC)

text: my comments come from, reading hundreds of posts on Optiboard forum. I will try to cite something, but it is difficult, as there is much conflicting info, and lots of advertising copy. Apologies to everybody,BTW. None of my comments apply to photography lenses. CorvetteZ51 (talk) 15:56, 29 February 2008 (UTC)
replies: text: That's what I was afraid of.  We can't have you putting in stuff that learned from reading forums.  That's just hearsay, not backed up by anything reliable. Dicklyon (talk) 18:07, 29 February 2008 (UTC)

text: D., you will find this interesting. http://www.opticampus.com/cecourse.php?url=lens_design/&OPTICAMP=f1e4252df70c63961503c46d0c8d8b60#asphericity
go down about 90% of the page, to 'Aspheric Lens Design'. Uf you have something more reliable, please indicate. CorvetteZ51 (talk) 11:55, 1 March 2008 (UTC)
replies: text: Thanks, looks like an OK source. Dicklyon (talk) 16:04, 1 March 2008 (UTC)
thread_title:  the current article is complete BS 

message: What is this paragraph trying to say? The wording is very confusing. --Srleffler (talk) 19:16, 8 November 2008 (UTC)
thread_title:  Confusing paragraph 

message: These notes did not conclude with why the Hubble is obsolete.  They continue to describe a flat array of sensors, each fitted with composite optical tubes that resist internal reflections but are durable in extreme conditions, where precision of the flatness of the sensor plate that contains the array was determined by a count of Newton rings.  They go on to say that image details are limited only by available computing power, based on the software program running (256)^2 attributes per pixel in an array of 1920X1080 pixels at 30 fps.  This optical system does not use any reflecting lenses, and the array being flat limits it's use solely to astronomical surveillance. StationNT5Bmedia (talk) 15:57, 10 November 2008 (UTC)
replies: text: This topic migrates from aspheric to afocal, but unlike current material on digiscoping, the descriptions are not reflecting, less refracting, and more of a warp of electromagnetic flux that funnels into successively smaller diameters of re-collimated waveforms, ultimately reaching an array with enough energy to trigger components that begin the initial electronic processing used to interpret point-to-point facsimiles of objects several light years wide upon sensor arrays that detect infra-red, ultra-violet, and visible light spectrums.  StationNT5Bmedia (talk) 20:36, 10 November 2008 (UTC)

text: I can't tell whether the text you have written here is an incoherent explanation of some other work, or original research, or complete nonsense. Fortunately, it seems to be completely off-topic for this article, so no further analysis of it seems necessary.--Srleffler (talk) 04:17, 11 November 2008 (UTC)
thread_title: the obsolete Hubble

message: The diagram needs to have definitions for all the quantities e.g. R is the radius of curvature, etc.  —Preceding unsigned comment added by 128.250.51.155 (talk) 21:24, 7 February 2010 (UTC)
replies: text: Yes, this is where math often fails in working with optics.  Because the variables are measurements indexed in units defined by previous work, we're using values that rarely match calibrations used to categorize power, curvature, and other properties.  The textbooks leave little comfort concerning the definition of quantities.  Very few texts give a chart of definitions:  they only include the inference from context building an equation.  Most useful would be a legend of the math symbols, units, tolerances, and other properties.  From the standpoint of engineering, a legend would seem more practicle & less theoretical.  StationNT5Bmedia (talk) 15:34, 10 February 2010 (UTC)
thread_title:  Define all quantities 

message: I am pretty sure this formula is wrong. z cannot be as defined as it does not reduce to a sphere for any value of k (with the As zero). I think z(r) is meant to be the Saggital Distance, often called SAG, not as it is at the moment "the z-component of the displacement of the surface from the vertex, at distance r from the axis". Billlion (talk) 14:44, 15 January 2011 (UTC)
replies: text: That is what sag is, and the article says that z(r) is the sag. I'm pretty sure the formula is right.--Srleffler (talk) 15:50, 15 January 2011 (UTC)
replies: text: Yes thanks, I am convinced now. I wrote out a quick derivation here  as I still haven't found it elsewhere. I wonder if anyone knows of a paper explaining why this series is a good one for optimising aspherical lenses? Billlion (talk) 14:57, 16 January 2011 (UTC)
replies: text:  I was confused by the term Sagittal Depth  "Sagittal Depth. Sagittal depth is the distance from the vertex of the contact lens surface to a chord drawn across the surface at a known diameter." Billlion (talk) 15:03, 16 January 2011 (UTC)
thread_title: Wrong formula?

message: An aspheric lens in ophthalmic optics don't always have rotationally symmetric surfaces. For the correction of astigmatism an aspheric ophthalmic lens has a single aspheric surface with rotational symmetry, and a toroidal surface which is not rotational symmetric. Some lenses even have a non-rotationally symetric aspheric surface (eg. a biaspheric ophthalmic lens for the correction of astigmatism) The term "whose surfaces have a profile that is rotationally symmetric" should be removed. Its liam (talk) 12:26, 23 March 2011 (UTC)
thread_title:  rotational symmetry  

message: I am trying to figure out who manufactures ultra short throw lenses, and I'm trying to find some sort of history or discussion of how they are developed. I work with these on a regular basis and I am interested to know where the technology originates.
Since the lenses are permanent components of projectors, the projector manufacturers have no need or desire to tell where they get their lens assemblies from.
There are now several extremophile lens systems out there where the projected image is bent at nearly an 80-degree angle towards the bottom of the screen, from a wall mounted projector directly above the screen without any arm holding it out in space a meter or more away. I am really interested to know what the shape profile is of these lenses and how the lenses are being manufactured, and it would probably make a useful addition to this article as well.
DMahalko (talk) 10:24, 27 June 2011 (UTC)
replies: text: Sounds like something that might well be proprietary: the projector manufacturers may well design their own lenses and have them custom-made.--Srleffler (talk) 00:37, 28 June 2011 (UTC)
thread_title:  Ultra short throw projector lenses? 

message: Shouldn't the h label in the diagram on the right side not be a r to fit with the formula? (Forgive me my ignorance, these are one of my first words on Wikipedia and I didn't find another place to put my comment)  — Preceding unsigned comment added by Halirutan (talk • contribs) 02:28, 6 December 2012 (UTC)
replies: text: Yes, you're correct, and this was exactly the right place to put your comment. I think the notation in the formula is better, since the surface profile is really a function of radius, not height. We should probably edit the image or replace it with a better one.--Srleffler (talk) 03:58, 6 December 2012 (UTC)
replies: text: The Diagram has been modified by the original auther, so as part of tidying up the Reqdiagram page, I am removing the Diagram Requested tag. Egmason (talk) 10:44, 1 June 2014 (UTC)
thread_title:  The label h is not correct 

message: These two pages contradict each other on the optical quality of the Visby lenses:  
http://en.m.wikipedia.org/wiki/Aspheric_lens:  The Visby lenses...exhibit a wide variety of image qualities....
http://en.m.wikipedia.org/wiki/Visby_lenses:  (The lenses) are so well produced that even computer optimisation has not been able to improve their performance.
Pollifax (talk) 03:25, 24 April 2015 (UTC)
replies: text: This article was right. The Visby lens article contained some statements that were not supported by the cited sources. The Schmidt reference cited there describes a study of seven of the lenses, only two of which showed signs of having been optimized for good image quality, and one of the two "good" lenses had an apparent manufacturing error—a misalignment between the optical centers of the two surfaces. The blanket statement that "the lenses are so well produced..." is clearly contradicted by this source, so I have removed it. I highly doubt that that statement would be true of even the best of the lenses, impressive as its imaging quality may be. --Srleffler (talk) 05:52, 24 April 2015 (UTC)
thread_title:  Contradiction with another page 

message: I added a section for discussing camera lenses and moved the information on the abbreviation there. I removed the list of camera lenses. I don't see a list of every aspheric camera lens ever made to be a useful addition to the article. I also question whether Wikipedia ought to have articles on individual specific models of camera lens.--Srleffler (talk) 21:09, 22 November 2015 (UTC)
thread_title:  List of camera lenses 

message: Substituted at 08:27, 29 April 2016 (UTC)
thread_title: Assessment comment

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