Talk:Zoom lens

Invention

Who invented the zoom lens? How does it work (specific technical details)? Michael Hardy 19:30, 30 Oct 2003 (UTC)

The fact that combining various lenses would result in a change of the aggregate focal length has been known since at least the 19th century. The difficulty is more in the actual implementation (optical and mechanical) than in the concept proper.

Aperture

I'm not conviced by the end of the article, after all the first Zoom for 35mm photography had an aperture of f/2.8. As far as I know it was very sharp and very expansive. You will find a better range than 36-82 mm today but not more aperture. BTW they are some ready-made idea that I believe wrong like "progress in optical design", there's is not a huge technical progress : what you pay when you buy a lens was for a large part computation time I read somewhere that Zeiss used 200 persons for computation before WWII you can imagine that computers have radically changed the costs of lens design. Ericd 09:35, 12 Oct 2004 (UTC)

I don't know much about that particular lens, but the references I read said that early zooms, particularly those that maintained constant aperture across the zoom range (as I believe that one did, and many modern consumer-grade ones don't try to do) suffered rather badly from aberrations, particularly field distortion. They were certainly much inferior of fixed lenses of the same era. -- DrBob 16:12, 12 Oct 2004 (UTC)

What you've read is not really inexact but simplistic IMO. Everybody agree that aberration issues will be more complex to fix on a zoom than a fixed lens. I don't think they were any theorical breakthrought in optics since the 50's. On the other hand I'm quite certain they were some progress in optical glasswork. Can we consider that old zooms were bad while modern zoom are good ? I don't think so. We will stick to 35mm photography to illustrate my POV the first Zoom is the Killfit Zoomar of 1959 it has an aperture of f/2.8 and a range of 36-82mm f/2.8 is a serious aperture for a zoom even today. The range is bit limited by today standards but those who tried it considers that it was a sharp lens. But this lens was very expansive. Why was it so expansive ? Because it's design required a huge time of computation on the top hardware of that time. In the same way I have a Minolta Rokkor 100-200mm f/5.6 that was the first zoom produced by Minolta it was introduced in the 60's it has limited aperture and range but is pin sharp it was also expansive but much cheaper than the Zoomar. Why ? As it has limited range and aperture it required less computation that the Zoomar it was also designed later when computers were more powerful. Things began to change in the 70's when Zoom become popular on the amateur market. Price was an important variable in the competition and reducing computation was a mean to cut down the price at the expanse of quality. Quality of consumer-grade zooms has improved because since the 70's because today any PC has enough CPU power to compute an excellent Zoom at low cost.

Ericd 18:05, 12 Oct 2004 (UTC)

To believe that early zoom lens designs of the sixties had and optical quality comparable to today's is ridiculous. This ignores the progress on optical design of the past few decades. Early zoom designs typically consisted of three lens groups (convergent,divergent,convergent); the 2d group was fixed, and the 1st and 3rd groups were mobile. Furthermore, the 1st and 3rd group were rigidly linked, so that a complex and difficult to manufacture non-linear cam-based group distance regulation mechanism wasn't needed. The downside of the rigid linking was that such a design can limit optical aberrations only over a very limited focal length range.

The development of sophisticated complex non-linearly driven four-group based designs (focusing, variator, compensator, relay master) is a fairly recent phenomenon that has been enabled by the development of new optical design techniques, computation algorithms, manufacturing — e.g. lower cost aspherical lenses, numerical control machines to manufacture precise non-linear driving cams — and material science — e.g. glasses with anomalous dispersion characteristics.

It seems appropriate to add some info here on how the variable and constant aperture lenses work and how they differ from each other. Does anyone have good info sources on this matter? Google mostly gives smoke and mirrors and also certain usability advantages of constant aperture, but not the specifics of how the optical schema differs.

The Voigtländer Zoomar is given a modern assessment here: https://www.ephotozine.com/article/voigtlander-zoomar-36-82mm-f-2-8-vintage-lens-review-32885/verdict and, frankly, while it's desirable as a collector's item and a piece of history, its optical performance is disappointing. 87.75.117.183 (talk) 18:11, 1 January 2021 (UTC)

Telephoto / Zoom

There is duplication between this article and telephoto lens. I think the two articles should be combined. I think a zoom lens should be a subcategory of telephoto lens, as the distinction is basically a zoom lens is a telephoto lens with a varying focal length. The issues as to what a focal length is, what an angle of view is, and how these things are related are common to both. Furthermore, the artistic aspects of using a telephoto and zoom to me seem to be the same. Bottom line, there is information in the zoom article that relates to telephoto and vice versa. --Lenehey 22:33, August 22, 2005 (UTC)

No, it's not. A telephoto lens is a long lens; a zoom lens is one with a variable focal length. Any confusion is due to the common use of phrases like "zoom in on that", and does not reflect inherent overlap in the article subjects. A 10-22mm zoom is hardly a telephoto, now is it? ('Course, the articles could both point out that the common confusion.) grendel|khan 04:04, August 23, 2005 (UTC)

I agree with Grendelkhan. Not all zoom lenses are telephotos, and not all telephotos are zooms. This is adequately explained in this article, but could be expanded in telephoto lens. -- DrBob 18:10, 23 August 2005 (UTC)

Copy of my answer on Talk:Telephoto lens :

NO ! It's a common confusion. A telephoto is not a zoom. And the artistic aspects of using a telephoto and zoom aren't the same especialy if we extend the topic to the use of zoom in movies and video. There's a (very incomplete BTW) article about photographic lenses another, another about wide-angle lenses, another about normal lenses, another about zoom lenses and I think it should stay like this. Ericd 21:40, 23 August 2005 (UTC)

Error in animated graphic?

The animated graphic, Simplified zoom lens in operation, seems like it contains an error. It appears that both the incoming light rays and the projected light rays move as the optics move. It seems like the incoming light rays should stay fixed and the projected light rays should move. Am I missing something? —Preceding unsigned comment added by John0720 (talk • contribs)

Interesting observation. The blue rays (the ones that change) are parallel to each other, and to the lens axis, throughout the animation. Thus they are all consistent with the same source, an on-axis point source at infinity. (You could say that there are infinitely many rays from the source to the lens, and the animation is just choosing a different set of three to plot at each step of the animation.) The question is, why is it picking different rays to plot? My best guess is that as the lens moves to its "wide" setting (interior element moves to the right), on-axis incident rays arriving at the edge of the front element would be obstructed by baffling and wouldn't contribute to the image. Note that the full area of the rear elements is used throughout the animation, even as less and less of the front element is used. -- Coneslayer 19:11, 6 July 2006 (UTC)

Different zoom technology

The Panasonic Lumix TZ1 has a compacted zoom lens technology. Though it is the size of a compact digital camera, it can still zoom up to 10x or 12.5x. They won the TIPA award for smallest camera with the largest zoom in 2006. 128.6.175.77 21:02, 12 July 2006 (UTC)

Well thats all well and good, but unless Panasonic has some product literature on it (something like Canons White papers) this information cannot be included, besides, this isn't that relevant to this article anyway. --122.104.46.186 (talk) 11:41, 28 December 2007 (UTC)

lesser quality than prime : fact?

Could it be possible to stop spreading old women tales? Some references would be welcome. --Marc Lacoste 15:25, 28 December 2006 (UTC)

There are many hundreds of references available to support this claim. Please choose one. Then could you help me find a reference showing that gravity is still real in 2008?

Your comment about women is inappropriate. Regardless, this is common knowledge amongst professional photographers. A reference could be a site like Photozone, where the lens performance database clearly shows prime lenses and the best low-ratio zoom lenses performing ahead of high-ratio zoom lenses. --Stybn 16:08, 1 February 2007 (UTC)

For those of us that don't find these things obvious(me), a citation would be appreciated. I looked at the link you gave, and saw no real information on the subject. HighInBC ^{(Need help? Ask me)} 16:11, 1 February 2007 (UTC)

There are many, many, many citations available. Each is subject to some level of nitpicking. —Preceding unsigned comment added by ForrestCroce (talk • contribs) 04:01, 23 January 2008 (UTC)

Old wives' tale documented. --Stybn 16:19, 1 February 2007 (UTC)

(edit conflict)I appreciate that you provided a citation. However the table of information does not support the statement Currently, photographic zoom lenses beyond about 3× cannot generally produce images of a quality on par with prime lenses. I believe you have made the mistake of synthesizing published material to advance a new position. This is a form of original research. What that citation shows me is a dataset, and what you are citing is an interpretation of that dataset. What is needed is a citation showing that interpretation of that or other data that supports the claim being cited. HighInBC ^{(Need help? Ask me)} 16:23, 1 February 2007 (UTC)

First, I agree that Currently, photographic zoom lenses beyond about 3× cannot generally produce images of a quality on par with prime lenses is overreaching. However, I think it's supportable to say that a prime lens costing x will have superior image quality to a zoom lens costing x, in general. (I think I remember the aphorism "cheap, fast, zoom--pick any two", but I might have just made it up, and it doesn't exactly fit.) It's a general rule, not a hard and fast one--besides, if you spend enough money, you can get a zoom lens just as sharp as a any prime. The statement should be revised to something like In general, photographic zoom lenses with image quality comparable to a prime lens cost far more than the prime lens. grendel|khan 16:33, 1 February 2007 (UTC)

If it is supportable, then a citation should be available, I agree with the fact you are presenting, I am just not so sure that I don't want a citation. HighInBC ^{(Need help? Ask me)} 16:47, 1 February 2007 (UTC)

I don't have the time to dig up a real citation, or put up a web page that expresses this interpretation, for linking. I know it from having a formal photography education, and from visiting untold numbers of websites where a low-ratio zoom is compared favorably to a prime, or a high-ratio zoom disfavorably. If someone agrees and would like to dig up a citation that distills all of this, great. Otherwise, no contest. --Stybn 17:05, 2 February 2007 (UTC)

I removed the photozone link, it's only an informal survey. I never saw a serious citation, only ad-supported websites and magazines. This doesn't say it's false, but it's unverified and is only propagating rumours, of which wikipedia should be free. --Marc Lacoste 17:18, 28 April 2007 (UTC)

From Cambridge in Colour: Understanding Camera Lenses

The primary advantages of prime lenses are in cost, weight and speed. An inexpensive prime lens can generally provide as good (or better) image quality as a high-end zoom lens. Additionally, if only a small fraction of the focal length range is necessary for a zoom lens, then a prime lens with a similar focal length will be significantly smaller and lighter. Finally, the best prime lenses almost always offer better light-gathering ability (larger maximum aperture) than the fastest zoom lenses-- often critical for low-light sports/theater photography, and when a shallow depth of field is necessary.

I would say it is general photographers knowledge that the Best Zoom lenses can only approach the quality of equivalent prime lenses. --122.104.46.186 (talk) 10:19, 28 December 2007 (UTC)

Design

The animation is not good I guess, lights from both image and object are moving with the movement of the inner lense ! this is misleading.

1) the light coming from an object should be independent of the movement of the lense

otherwise

2) the visible movement of the image can either be due to the movement of the object and/or movement of the lense. Which makes the animation not very good since it cannot show the effect of the lense exclusively.

Jeroje 04:10, 10 August 2007 (UTC)jeroje

I think you're raising the same objection as in Error in animated graphic? above. Please see my response to that question, which concerned an earlier version of the animation. -- Coneslayer 19:54, 10 September 2007 (UTC)

Well, since the question was raised twice... and I too have problems with the animation, I guess the animation is not clear enough - with or without your explanation (which is not included in the article), the point is not made. The animation should clear the workings of the zoom lenses for everybody, but as is, it's only confusing. So I think it should be changed.89.137.187.148 (talk) 19:40, 21 December 2011 (UTC)Apass

Addition by 62.1.109.237

62.1.109.237 added the following paragraph:

The bigger the zoom ratio, the higher the design complexity of the lens, its bulk and concomitant cost, and the more prominent the optical quality loss. This is significantly masked when recording moving images, which is why video and TV lenses are able to achieve very high zoom ratios. It is also somewhat masked by digital camera sensor sampling, but less so in professional-standard medium and large format photography, both digital and analogue film. Nevertheless a capable zoom lens, with its flexible framing and ease of composition can be invaluable in demanding situations such as news photography. Digital photography can also accommodate optical correction algorithms that partially compensate for optical flaws, both within in-camera processors and in production software.

The statement that larger zoom ratios equate to higher design complexity, bulk, and cost is unreferenced and wrong in my opinion — the most complex, bulky, and expensive zoom lenses are low-ratio large-aperture professional zooms. The statement about quality issues being "somewhat masked by digital sensor sampling" is extremely vague and also unreferenced — if it refers to issues being masked by low sensor resolution, one only needs to scan some reviews of cheap zoom lenses to see otherwise. This I removed these two statements from the article. --Stybn (talk) 16:50, 24 June 2009 (UTC)

Suggestion

It would be awesome if someone found/made a photo at 1x zoom, then drew smaller and smaller rectangular crops representing each zoom level, 3x, 5x, etc... It would be similar to this http://en.wiki.x.io/wiki/File:Vector_Video_Standards2.svg . I am currently searching for something like that to help me decide what level of zoom I want in a camera, and hoped to find one here. Or even photographic samples of 1x, 3x, 5x, 10x of the same subject would do well. Habanero-tan (talk) 21:30, 13 July 2009 (UTC)

Yes, it is a good idea. The difference in angle, or size of the image, should be common with prime lenses, but the need for illustration is noted. There is the thing about change in perspective as well (standing close to the subject with a wide lens vs. standing far with a long lens). I do not have the time now to add links, might try later. Thermofan (talk) —Preceding undated comment added 07:41, 17 September 2011 (UTC).

Superzoom?

A lens with a focal length range greater as factor 5x is called superzoom.

RM'ed above statement to talk because it's unverified. Parent article Superzoom also contains no reliable sources as to what a "Superzoom" lens is. Fountains of Bryn Mawr (talk) 19:08, 1 December 2012 (UTC)

diagram of parts of a typical lens

I wish this article had a diagram labeling the parts of a typical zoom lens.

By "typical", I mean the parts that typically are included in the thing people buy and attach to the front of a camera -- not just the lenses, but also the lens barrel, the mounting flange, the flange focal distance, the throat, the breech, the image circle, the anti-reflective coatings, the filter mount, etc.

In particular, what is (are) the name(s) of the 2 gear-like rings that many commonly available zoom lenses have, that are designed to be gripped by a human hand and turned -- turn one to change the zoom, and turn the other to change the focus? --DavidCary (talk) 00:01, 8 May 2014 (UTC)

True Zoom info is silly

There are several places in the article that reference "true zoom" and claim that varifocal zoom lenses are not zoom lenses. But there are no sources to back that up. The only source used actually doesn't make the claim at all. Does anyone have any reliable sources that discuss "true zoom" and/or "varifocal not a zoom" info? If not I think I'll do a clean-up and remove this apparent misinformation. CodeCurmudgeon (talk) 18:04, 23 May 2016 (UTC)

I agree the term "True Zoom" is meaningless and silly. There are parfocal zoom lenses and varifocal zoom lenses and that's all there is to it. 87.75.117.183 (talk) 18:39, 1 January 2021 (UTC)

Etymology

Hello, Does anyone knows how and when the word "zoom" was first applied to a lens with a variable focal length ? Thanks ! Douzelignes (talk) 16:51, 8 February 2017 (UTC)