Talk:Camera lens

Too many diagrams

The "History and technical development of photographic camera lenses" section has way too many lens diagrams that detract because of poor image choice and placement, are too redundant (3 images with 26 diagrams each?), and even ask leading questions re: "Which is the Sonnar, which is the Planar?" (See WP:NOTREPOSITORY and WP:IMAGES). Moved or removed all of these to try to fix the problem. Fountains of Bryn Mawr (talk) 23:04, 17 December 2010 (UTC)

I tagged the section for WP:OR and {{Essay-like}}. The section starts like a stand alone non-encyclopedic essay on lenses and pretty much stays that way with way to many unsupported statements. It also is a redundant version of many other articles sometimes without even even linking them (Anti-reflective coating, Mangin mirror, Teleside converter, etc), Needs lots of cleanup. Fountains of Bryn Mawr (talk) 23:42, 17 December 2010 (UTC)

The diagram "Which is the Sonnar; which is the Planar?" was included because a statement was made in the text saying that it is difficult to tell the difference between a modern Sonnar and Planar lens. It illustrated that point by showing their similarity. The question was answered in the diagram's text, if you look at it.

A large number of Double Gauss lenses were illustrated because of the extreme variety of that design, also discussed in the text. In fact, all of the Double Gauss lenses named in that section were shown in the diagrams to allow readers to compare them with each other (and the others shown).

What "many unsupported statements" are you referring to? If you point them out, I can include references for them. I had thought the 300 footnotes I had already included were enough. Paul1513 (talk) 20:02, 23 December 2010 (UTC)

The purpose of Wikipedia is to describe "things" clearly to the average reader, not to teach subject matter, ask leading questions, or create a huge laundry list of all types (WP:NOTTEXTBOOK and WP:INDISCRIMINATE). You may want to see if you can rewrite the section to be a summary of lens types easily understood by the laymen (or other editors will probably do it over time). The example of the 78 images of a Double Gauss lens is unclear because the thumbs are not readable and in fact push them selves and the images below them right out of context in a nasty "image stack" (WP:IMAGES). The place for such extensive detail is the Double-Gauss lens article. You may want to look into WP:SUMMARY for tips on how to write/sync up a summary and a full article. You may want to look into Wikibooks as a place to host a textbook type article.

Re: "many unsupported statements", it starts in the first paragraph with the unsupported statement "The first century of the history of the photographic camera lens can be understood as a slow increase of optical knowledge; enough to bring optical aberrations of real lenses to an acceptable level. The second century of the history of the photographic camera lens can be regarded as technical applications of that knowledge; to slowly increase the variety and versatility of real lenses" and goes on from there re:

"The zoom lens is a natural consequence of the telephoto lens (q.v.), the original lens to manipulate focal length"

"The increasingly complex internal movements of zoom lenses also inspired improved prime lens designs."

"The hunger for one lens able to do everything, or at least as much as possible, is probably the other great influence on lens design in the last quarter century."

"The history of the photographic camera lens began with the Wollaston Meniscus" has no meaning and is contradicted in the next paragraph re: Niépce's biconvex lens, and is also contradicted by reference[1][2] that the first photographic camera lenses were the biconvex and the Achromat.

I did a cleanup of the "The catadioptric "mirror" lens" section (something I know a little about) citing many unsupported statements and removing others because they made no sense such as "The Mangin was favored by the Japanese lens makers" - Mangin what? Does this mean solid catadioptric? Fountains of Bryn Mawr (talk) 03:49, 29 December 2010 (UTC)

On the one hand, I love this reference of the history of lens design; on the other hand, it is out of hand. It is well-done and useful, however it goes far beyond explaining what a camera lens is and so is out of scope for this page. Perhaps some of it should be reduced to an overview with the details moved to a Wikibooks page "history of the photographic lens"? —Ben FrantzDale (talk) 14:21, 3 January 2011 (UTC)

I agree. This is an appropriate situation for a fork. Dicklyon (talk) 17:05, 3 January 2011 (UTC)

The "The apparent influence of lens focal length on image perspective" section was not "largely nonsense" and should not have been deleted. It was a natural continuation of the "Aperture and focal length" section. (I did not write either section.)

In photographic composition, the real or apparent perspective of a photograph can be manipulated by the lens in varied ways to frame a scene in a desired way. A) Selecting lens focal lengths versus the image format diagonal for particular angular field of views. B) Positioning the lens at specific object distances for preferred image magnifications and perceived positions in relative space. C) Using different aperture sizes to control what object distance zones are imaged as sharp or blurry (see depth of field and bokeh) and D) by shifting relative lateral, pitch, roll and/or yaw positions between the image capture medium and the lens' image plane for perspective and plane of focus control (see Scheimpflug principle). These compositional techniques have been used by photographers for many decades and, although the section may be difficult to understand, I am surprised that Blouis79 did not recognize them.

For example, the "portrait lens" that Blouis79 dismissed. The 90 to 105mm focal length has been the standard portrait lens on the standard 24×36mm 35mm film format for sixty or seventy years, for exactly the reasons given. It allows a tight head and shoulders composition at a distance that does not invade the sitter's personal space while producing natural looking features – no bulging nose and receding ears as with a wider lens, nor face flattening as with a longer lens. Foreground and background objects also appear natural but can be separated from the sitter with appropriate aperture selection. What the section needed was a rewriting for better clarity, perhaps with illustrative samples and diagrams.

The reflector telescope history recap that I wrote should not have been deleted either. The history of the telescope from the point of view of general photography is very different from the point of view of astronomy. A reflector telescope is fundamental for an astronomer, but a "CAT" is a rare and specialized tool for a photographer, with a lineage completely different than any refractive lens. A few paragraphs reviewing that lineage is not "redundant" for a section titled "History and Technical Development of Photographic Camera Lenses." Perhaps that is why you reacted so negatively to it – you're thinking about astronomical telescopes.

I feel that your criticism about a shortage of intra-Wikipedia links is unjust, because I put over sixty in the History section. If you wish to add more, there is nothing stopping you. What it really needs are intra-article links to replace the quo vide's.

About the "original research" tag. There is no original research in the History section; everything is adapted from the 170 sources given.

About the "essay" tag. I tried to give overall coherence and unity to the History section, which I think is proper. Are you saying that I did it badly or that I should not have tried? Are you saying that I biased toward one optical company? I thought I spread the kudos around to all appropriate entities. (You should read the History section of the Photographic Lens Design article. Zeiss this; Zeiss that; Zeiss everything! Zeiss was only dominant between 1890 and 1940.) If you are saying that my writing style is not the same as yours, and therefore my writing is invalid, I forcefully object.

About your citation request for the sentence: "Dmitri Maksutov's original MTO (Maksutov Tele-Optic) 500mm f/8 (Soviet Union) of 1944 was the first general purpose photographic catadioptric lens." which you changed to "Dmitri Maksutov adapted his 1941 Maksutov telescope design for use as a photographer's camera lens in a Maksutov–Cassegrain configuration in 1944, his MTO (Maksutov Tele-Optic) 500mm f/8, the first general purpose photographic catadioptric lens." There is a citation already.

I see that you changed to 1941 from "circa 1942" when the Maksutov-Cassegrain was invented. Do you have source for that exact year? This is a sincere request, because I couldn't pin down an exact year from the standard photographic references. Kingslake said developed "around 1941" and paper in English published "1944." (Rudolf Kingslake, A History of the Photographic Lens. San Diego, CA: Academic Press, 1989. ISBN 0-12-408640-3. pp 177-179, 253.) Ray said "early 1940's." (Sidney F. Ray, The Photographic Lens. Second revised edition. Oxford, UK: Focal Press/Butterworth-Heinemann, 1992. ISBN 0-2405-1329-0. p 168.) Thanks.

About your citation request for: "Dedicated photographic mirror lenses fell out of favor in the 1980s for various reasons." I think that you're asking for a clarification of the various reasons, right? How about: "Dedicated photographic mirror lenses fell out of favor in the 1980s with the arrival of apochromatic super-telephoto lenses. The CAT's central secondary mirror obstruction caused unique "donut" rendition of blurry specular highlights, producing strange bokeh (q.v.) which was trendy when novel, but fell out of fashion. It also prevented the fitting of an adjustable aperture diaphragm, and limited light transmission by about a stop, with lowered image contrast. The dim light transmission also often prevented the autofocus systems on the newly available 35mm autofocus SLR cameras from working. Refractive apochromatic super-telephoto lenses using extra-low dispersion glasses (q.v.) do not suffer from these problems. Only one CAT was ever produced in a 35mm autofocus (q.v.) mount, the Minolta AF Reflex 500mm f/8 (circa 1990), for Minolta Alpha/Maxxum/Dynax 35mm SLRs." (Keppler, Herbert. "SLR: The CAT did it: Want a tiny 500mm supertele for $100 or maybe $69? Read on." pp 34, 36, 38, 40. Popular Photography & Imaging, Volume 67 Number 8; August 2003. ISSN 1542-0337. pp 36, 38.)

Also your citation request for: "The CAT is the only reasonable solution for 1000+ mm lenses." This is also a clarification request, right? I can expand the sentence to: "The CAT is the only reasonable solution for 1000+ mm lenses, because an ultra-telephoto CAT lens is much easier for a designer to correct for chromatic aberration and a photographer to handle than a refractive ultra-tele." (Stafford, Simon and Rudi Hillebrand & Hans-Joachim Hauschild. The New Nikon Compendium: Cameras, Lenses & Accessories since 1917. 2004 Updated North American Edition. Asheville, NC: Lark Books, 2003. ISBN 1-57990-592-7. p 184.) Sorry for the ambiguity. In any event, the statement is presently hypothetical, because there are no general purpose photographic lenses of more than 800mm focal length available from any major maker in at least seven years. Paul1513 (talk) 19:20, 3 January 2011 (UTC)

Just as a footnote, I believe that at least some of the current content could and should be moved to Photographic lens design but I have been reluctant to do so myself as I have a vested interest here as creator of the article and I would prefer others to take a less partial view.  Velella  ^{Velella Talk}   20:05, 3 January 2011 (UTC)

Agree with the footnote, this should be moved to "Photographic lens design"

I did a content swap on the double Gauss lens section to Double-Gauss lens re: making this article a summary. So the short summary from that article is here and the detailed section is now there. Restored most of the diagrams there to save them from deletion.

Re: the "1944, (Maksutov Tele-Optic) 500mm f/8, the first general purpose photographic catadioptric lens". The citation does not look reliable and what is being cited is unclear although I see other non-wikipedia mirror mentions that this was its introduction. 1944 would be the year Maksutov published the invention of his Maksutov telescope. Did he publish a camera lens design that same year? Did he demonstrate a lens he had built? Or is this a camera lens built at a future date based on Maksutov's 1944 paper? Needs clarification.

Re: the "circa 1942" invention of the Maksutov-Cassegrain -- have a look at Maksutov telescope for some referenced history but, yeah... its hard to nail down when it (or any design) was converted into a cassigrain. Maksutov invented a telescope in 1941, but not necessarily a cassigrain. A Cassigrain is simply one adaptation of the telescope type to bring the image behind the mirror. Maksutov's prototype was supposedly a Gregorian design. What other image planes he used I have not seen a reference to. He hinted at spot-mak cassigrain designs in his papers. I saw a 1946 patent for a non-spot convertible Maksutov cassigrain/Newtonian by Questar's Lawrence Braymer so it looks like lots of designers were jumping all over the design as soon as they heard about it. I have thrown in another edit on the section to beef it up re: "point of view of general photography". Fountains of Bryn Mawr (talk) 03:42, 8 January 2011 (UTC)

About your citation request for the sentences: "The first century of the history of the photographic camera lens can be understood as a slow increase of optical knowledge; enough to bring optical aberrations of real lenses to an acceptable level. The second century of the history of the photographic camera lens can be regarded as technical applications of that knowledge; to slowly increase the variety and versatility of real lenses." These sentences are introduction and are not intended to be immediately sourced. When I realized that the History section was getting very long, I wrote an introductory paragraph to frame the section. Each concept is sourced as they appear. However, if you insist: "Michael R. Peres; editor in chief, Focal Encyclopedia of Photography: Digital Imaging, Theory and Applications, History, and Science. Fourth Edition. Boston, MA: Focal Press/Elsevier, 2007. ISBN 0-240-80740-5. pp 157-158, 719."

About your citation request for the sentence: "The history of the photographic camera lens began with the Wollaston Meniscus." The citation at the end of the paragraph covers the entire paragraph.

You also say that the sentence is false. Of the two Google books sources that you gave, the first one is from 1897 and is out of date. It is generally agreed that the study of the history of photography begins with Helmut Gernsheim in 1945.

The second one does not support your claim. It says: "Wollaston recommended such a meniscus lens for the camera obscura in 1812. It was available as a camera lens from the very beginning of photography." This is consistent with what I wrote and sourced in the next paragraph: "the Meniscus is called the first photographic lens because it was fitted to some of the camera obscuras adapted by Joseph Nicéphore Niépce (France) to his pioneering 'heliography' experiments.…" The Meniscus replaced the biconvex lens during the course of Niépce's experiments because the required level of image quality for a photographic camera could not be met by a biconvex lens. The timeline of the Meniscus, Achromat Doublet and Achromat Landscape is explained (and sourced) in that subsection.

By the way, the earliest (late 18th century) light drawing experiments by Johann Schulze and Thomas Wedgwood did not involve any camera or lens at all. They produced "shadowgraphs" of objects placed atop light sensitized sheets.

About your citation request for the sentence: "The zoom lens is a natural consequence of the telephoto lens (q.v.), the original lens to manipulate focal length." This sentence is explained by the rest of the paragraph. At the end, there is a source for the whole paragraph. This is the second time this has occurred. Are you asking for a "one sentence, one source" standard?

About your citation request for the sentence: "The increasingly complex internal movements of zoom lenses also inspired improved prime lens designs." The optical similarity of zooming and floating elements/internal focus is from: Sidney F. Ray, Applied Photographic Optics. Third edition. Woburn, MA: Focal Press/Elsevier, 2002. ISBN 0-240-51540-4. p 88. By the way, I did not discuss the fairly rare "front cell focusing" in this subsection.

Are you sincere in your question of how a Mangin is related to a "solid catadioptric"? If you want, I can give you a block diagram of the (Perkin Elmer) Vivitar Series 1 600mm f/8 Solid CAT to compare with the Minolta 250mm RF diagram in the article. By the way, the lack of a physical hole in the Minolta's primary mirror is not typical of most Mangins.

Thanks for restoring a (shorter) CAT lens history.

About your citation request for the sentence: "The hunger for one lens able to do everything, or at least as much as possible, is probably the other great influence on lens design in the last quarter century." This sentence is both a bridge to the previous subsection and an introduction to the new subsection and is not intended to be immediately sourced. However, if, after reading the entire subsection, you are still convinced that zooms in general, and superzooms in particular, are not a major lens type in research and sales since circa 1985: Herbert Keppler, "SLR: Which general-purpose zoom should you buy?" pp 22-26. Popular Photography, Volume 64 Number 10; September 2000. It reviews the zoom lens choices available than.

About "original research" again. I am borrowing the photographic expertise of Helmut Gernsheim, the founder of the history of photography, Rudolf Kingslake, a fifty year veteran lens designer/instructor, Sidney F. Ray, a forty year veteran lens design instructor/textbook author, Herbert Keppler, a fifty year veteran journalist on photography, Arthur Cox, author of fifteen editions of Photographic Optics over thirty-five years, and the others I've cited. I am not interpreting them in an original manner.

On the apparently emerging consensus that I gave Wikipedia too much information. I'm getting a sinking feeling that I'm a fanboy who can't understand why everyone doesn't think that all this stuff is way cool. But hey, at least I didn't write about lens caps! (Yes, I have sources for them.) Paul1513 (talk) 19:15, 10 January 2011 (UTC)

Per Wollaston meniscus, its unclear wording that tries to follow what they should have used first instead of what they did use first, which refs point to as biconvex[3]. The section doesn't explain the basics to the reader like "why did they need this meniscus?"

The "Mangin" question was "what do you mean by a catadioptric Mangin?". I never heard of it. I was thinking "A solid CAT could be looked at as a very thick mangin with a silvered spot...hmm", so I looked it up (since the article gave no clue) and found the info on the series of mangin type CATs (which, of course, all the photographers mistake for Schmidts.. but there ya go ;)).

As to the rest of it, you seem to keep missing the point. You cite many many sources and then write a synthesis of those sources to introduce a paragraph or section. This is directly prohibited by Wikipedia policy re:WP:SYNTHESIS re - "Do not combine material from multiple sources to reach or imply a conclusion not explicitly stated by any of the sources. If one reliable source says A, and another reliable source says B, do not join A and B together to imply a conclusion C that is not mentioned by either of the sources." Yes I can look at your sources and reach the same conclusion you have. I can also look at your sources and reach the opposite conclusion. The problem is neither of us should be reaching conclusions at all, Wikipedia articles do not have editorial conclusions. So I am not saying what you wrote is not true, reading it I can come to the conclusion that some of it is "true", but the threshold for inclusion in Wikipedia is verifiability, not truth.

As to "too much information fanboy" I find it way cool to, and I find what you wrote informative, especially after I chase the stuff down to find out "hmmm.. what does this mean?" Its not bad stuff, its just stuff that needs to be cleaned up, what you added was an un-edited "information dump", welcome to Wikipedia - the place where thousands of editors will do that for you ;). Fountains of Bryn Mawr (talk) 22:29, 11 January 2011 (UTC)

I think it's cool, too, but way too much for this article. A separate article on the history of lens design would be a good place for it. Some of the general synthesis stuff can probably be found in Kingslake and sourced thereby. Dicklyon (talk) 01:54, 12 January 2011 (UTC)

• Just 2 cents: I found this article most interesting because of the large number of diagrams. --Janke | Talk 21:26, 12 January 2011 (UTC)

Unnecessary tags?

I agree that this article is way too in-depth and should be split. However, I disagree with the lack of references tag (300 references is certainly not lacking!) and the too technical tag (just casually browsing through the article, I got the gist of it). While I think the article deserves cleaning up, I also think these tags should be removed. AryconVyper (talk) 13:12, 14 February 2011 (UTC)

Number of references do not mean an article is reliably sourced, and this article is a classic example. The introduction makes some un-referenced (and wrong) statements about camera lenses. There are very few references (in fact 13) in the "body" of the article, before the history section. The history section has the vast majority of the references and, as I pointed out above, allot of those are primary sources supporting original research. too technical is discussed above as well but I would note allot of the problem is a mix of badly written non-encyclopedic tone and general photographer/hobbyist folk lore making parts of the article more mumbo-jumbo than "too technical". Fountains of Bryn Mawr (talk) 23:39, 17 February 2011 (UTC)

I too disagree with the lack of references tag (300 references is certainly not lacking!). Your "Systemic problems", even if existing, are not helpful to be tagged, when they are "systemic". Tagremover (talk) 21:50, 8 March 2012 (UTC)

Glass is the most common...

This statement- "Glass is the most common material used to construct lens elements" appears in the text and I really wonder if this is verified. Many eyeglasses use plastic lens as do many inexpensive cameras and decorative lighting instruments. Does someone really know? —Preceding unsigned comment added by 75.11.12.146 (talk) 08:50, 14 April 2011 (UTC)

You make a good point. While I am sure glass is the most common for serious camera lenses (the title of this page), "most common" isn't well-defined. By number of units, I bet plastic lenses are actually more prevalent, given the billions(?) of cell-phone cameras out there in the world. Also, I think aspherical plastic elements are gaining acceptance in expensive optics. Maybe something like "Historically, glass has been the dominant material for building quality optics; recently, plastics have been used increasingly in everything from eyeglasses to cell-phone cameras to elements in high-end optics, particularly due to the ease of molding aspherical plastic elements." That seems to cover it but yet be vague enough to not be incorrect and to not require much citation. —Ben FrantzDale (talk) 12:41, 14 April 2011 (UTC)

Time-reversed signal processing

I am concerned with the following sentence, at the end of the "digital era" section.

In theory, if the physical characteristics of a lens are completely understood and the information in an image are completely known, the object can be mathematically recreated with near perfection, assuming no environmental degradation, because wave phenomena obey time-reversible equations. Presently, time-reversed signal processing techniques are used for sound and radio waves (for sonar and radar systems), but there is no fundamental reason why they cannot be used for visible light wave photographic systems.

The point here is with the wording "information in an image" which is technically incorrect. In order to "recreate the object" you need to know the full light field at the focal (or any) plane. Current image sensors (CCD, CMOS, film, just any image sensor) do sample only the light intensity incident on the surface of the sensor, as opposed to intensity plus phase (which would be needed at each wavelength). Moreover the intensity is integrated over broad regions of the spectrum (typically corresponding to three colors, or even the full visible spectrum for BW film). Since people doesn't consider such information as the full spectral content of light, let alone a complete description of the electromagnetic field, as part of an image, describing these data as "information in an image" is misleading.

Given the current image sensors, without some justification, the statement "there is no fundamental reason why they cannot be used..." sounds a bit like "there is no fundamental reason why we can not grow crops on the moon". Ok, true, but rather uninformative. — Preceding unsigned comment added by 89.154.29.221 (talk) 01:19, 14 July 2011 (UTC)

Its the tail end of a section that is just full of un-encyclopedic statements. The last sentence sounds like more WP:OR and probably falls under WP:CRYSTAL. Can be checked against references, or removed and the deletion referenced in talk so someone can get back to it and firm up if any of it is encyclopedic. Fountains of Bryn Mawr (talk) 03:35, 14 July 2011 (UTC)

Ok, checked against one of the sources cited at the end of that paragraph (Licker vol. 18) and there is no mention of any use of "time reversed" techniques for optical devices (just radio and acoustics). I don't have access to the second source, but its title is "Time-Reversed Acoustics". I would like to point out the claim of that paragraph is far too nonsensical to be supported by a mere article about an unrelated subject published on a magazine. I go on to delete that paragraph. — Preceding unsigned comment added by 89.154.29.221 (talk) 04:51, 14 July 2011 (UTC)

q.v.

What does this q.v. stand for? Does anyone else find 40 occurrences of q.v. distracting? Dzenanz (talk) 01:01, 11 September 2011 (UTC)

It means "quod vide", or "which see"; that is, "look it up". I think even one occurrence is distracting and inappropriate in a general-English encyclopedia (but then I also object to i.e. and e.g., which are sources of great confusion among readers and writers these days, too). We're not short on space, so there's no need to two-letter Latin abbrevs. Fix it. Dicklyon (talk) 01:33, 11 September 2011 (UTC)

Done. Dzenanz (talk) 03:16, 11 September 2011 (UTC)

In many cases, a wikilink would be the sensible alternative, in case the readers wants to "q.v." Dicklyon (talk) 04:49, 11 September 2011 (UTC)

Virtual image abuse?

In the "Theory of operation" section, the two references to the "virtual image of the aperture" seem inadvisable in such close association with descriptions and illustrations of pinhole imaging. Confusion about what virtual and real images are is a deplorable trend. Even recent editions of the formerly excellent Focal Encyclopedia have a brief "Virtual image" article stating that the image focused on a screen or film is a virtual image, which is of course exactly wrong, and that howling error, faithfully copied, has for several years now been corrupting visitors—yes, even innocent little schoolchildren—naively seeking information at the George Eastman House site, seemingly also a highly reliable source. Let's try not to add to the problem. I assume the point that someone was trying to make in this article is about measuring the effective aperture of a diaphragm in a lens system, but the context for making that point was either ill-chosen to begin with or has subsequently evolved to be unsuitable and misleading. 66.249.174.102 (talk) 06:57, 27 March 2015 (UTC)

Do we need a section on filters and hoods?

At present the article has a section on lens mounts. However, there's no similar section for filters and lens hoods that you attach to the front of a lens. --Marc Kupper|talk 23:18, 10 March 2016 (UTC)

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Convex lens

The phrase "convex lens" is used several times in the article without definition or explanation. I think this is the sort of thing that someone accessing this article would be looking for. A short explanation and diagram would be appropriate additions, together with a link to the article "Lens". I'm not an expert & am reluctant to edit. Ishboyfay (talk) 17:29, 1 April 2021 (UTC)

telescopic

a telescopic lens is similar 121.200.42.86 (talk) 08:27, 25 July 2022 (UTC)