322:
230:
148:
356:
positioned between the lens and its focal point, and the optimal observation occurs when the image is at the closest distance at which the eye can focus comfortably. The lens's magnification is the ratio of the image's apparent height to the object's actual height, correlating to the proportion of the distances from the image to the lens and the object to the lens. Moving the object nearer to the lens amplifies this effect, increasing magnification.
201:
478:
denote tools for users to find information or closely inspect content. The right-pointing version, U+1F50E (π), continues this theme, often used to initiate searches. The integration of these icons into user interface design reflects the intuitive connection between the physical act of magnifying to see more clearly and the metaphorical act of searching for information in the digital space.
140:
43:
345:, which is a different quantity). The magnifying power is the ratio of the sizes of the images formed on the user's retina with and without the lens. For the "without" case, it is typically assumed that the user would bring the object as close to one eye as possible without it becoming blurry. This point, known as the
418:
intense spot of light onto the tinder, awaiting ignition with patience. The advantage of this method is the simplicity of the lens and the minimal effort required. However, its effectiveness is contingent upon clear, strong sunlight, which may be inconsistent depending on geographic location and time of year.
477:
The magnifying glass icon (π), represented by U+1F50D in
Unicode, has evolved into a universal symbol for searching and zooming functions in digital interfaces. Originating from its practical use for detailed examination and discovery, it has been adopted by modern computer software and websites to
421:
Beyond survival uses, magnifying glasses are invaluable tools for jewelers and hobbyists. Jewelers rely on them to scrutinize the quality and authenticity of precious gems, ensuring accurate evaluations. Hobbyists, from those engaged in sewing and needlework to stamp collectors, depend on magnifying
417:
A magnifying glass can serve as a fire-starting tool in survival situations. Any transparent lens with significant magnifying ability, such as a standard magnifying glass or a jeweler's loupe, can concentrate sunlight to ignite tinder. The technique involves positioning the lens to focus a small,
425:
Advanced digital magnifiers and apps have emerged as modern alternatives to traditional magnifying glasses, offering features such as variable magnification levels, high-contrast modes, and text-to-speech for visually impaired users. These tools not only magnify text and objects but also enhance
396:
However, magnifiers are not always used as described above because it is more comfortable to put the magnifier close to the object (one focal length away). The eye can then be a larger distance away, and a good image can be obtained very easily; the focus is not very sensitive to the eye's exact
355:
A magnifying glass operates as the simplest form of optical instrument. It is essentially a hand-held lens that converges light to produce an enlarged, upright image that appears to stand where light doesn't actually converge, known as a 'virtual' image. To view an item in greater detail, it is
481:
Beyond its digital symbolization for search functions, the magnifying glass also holds a place in educational symbolism, often representing curiosity, exploration, and the quest for knowledge. Educational institutions and programs frequently use the magnifying glass in logos and materials to
181:
is usually mounted in a frame with a handle. Beyond its primary function of magnification, this simple yet ingenious tool serves a variety of purposes. It can be employed to focus sunlight, harnessing the Sun's rays to create a concentrated hot spot at the lens's
237:"The evidence indicates that the use of lenses was widespread throughout the Middle East and the Mediterranean basin over several millennia". Archaeological findings from the 1980s in Crete's Idaean Cave unearthed rock crystal lenses dating back to the
212:
The cultural impact of the magnifying glass extends far into the realms of literature and pop culture, symbolizing the pursuit of truth and the uncovering of secrets. It is famously associated with the investigative work of fictional detectives, with
458:
Such magnifiers can reach up to about 30Γ, and at these magnifications the aperture of the magnifier becomes very small and it must be placed very close to both the object and the eye. For more convenient use or for magnification beyond about 30Γ, a
197:, which, despite being significantly thinner, operates effectively as a single lens. This particular design finds its utility in applications such as screen magnifiers for TVs, offering a lightweight and efficient solution for enlarging visuals.
408:
of 25 cm, corresponding to an optical power of 4 dioptres. Such a magnifier would be sold as a "2Γ" magnifier. In actual use, an observer with "typical" eyes would obtain a magnifying power between 1 and 2, depending on where lens is held.
241:, showcasing exceptional optical quality. These discoveries suggest that the use of lenses for magnification and possibly for starting fires was widespread in the Mediterranean and Middle East, indicating an advanced understanding of optics in
422:
glasses for detailed work, enhancing both precision and enjoyment. This versatility underlines the magnifying glass's enduring utility across a spectrum of activities, from professional assessments to leisure pursuits.
321:
352:, varies with age. In a young child, it can be as close as 5 cm, while, in an elderly person it may be as far as one or two metres. Magnifiers are typically characterized using a "standard" value of 0.25 m.
434:
Magnifying glasses typically have low magnifying power: 2Γβ6Γ, with the lower-power types being much more common. At higher magnifications, the image quality of a simple magnifying glass becomes poor due to
374:, and the factor of 0.25 m represents the assumed near point (ΒΌ m from the eye). This value of the magnifying power is the one normally used to characterize magnifiers. It is typically denoted "
313:
improving on the device in 1609, employing the magnifying lens in an innovative manner, further extending the application of optical technologies developed through the ages.
301:
crafted the compound microscope by assembling several magnifying lenses in a tube, marking a significant advancement in optical instruments. Not long after,
451:. High power magnifiers are sometimes mounted in a cylindrical or conical holder with no handle, often designed to be worn on the head; this is called a
333:
of a magnifying glass depends upon where it is placed between the user's eye and the object being viewed, and the total distance between them. The
263:
wrote that it could be used to read letters "no matter how small or dim".) A convex lens used for forming a magnified image was described in the
359:
The highest magnifying power is obtained by putting the lens very close to one eye, and moving the eye and the lens together to obtain the best
274:
698:
713:
Kriss, Timothy C.; Kriss, Vesna
Martich (April 1998). "History of the Operating Microscope: From Magnifying Glass to Micro neurosurgery".
221:. Through its various forms and functions, the magnifying glass remains a tool of both practical utility and significant symbolic value.
799:
447:
provides higher magnification with improved image quality. Even better images can be obtained with a multiple-lens magnifier, such as a
780:
690:
126:
60:
840:
107:
79:
64:
86:
956:
93:
363:. The object will then typically also be close to the lens. The magnifying power obtained in this condition is
443:. When more magnification or a better image is required, other types of hand magnifier are typically used. A
75:
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readability and accessibility, making them invaluable for daily living and educational purposes.
260:
193:, employing numerous slender, concentric, ring-shaped lenses. These are collectively known as a
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by Henry C. King, Harold
Spencer Jones Publisher Courier Dover Publications, 2003 Pg 25
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916:"The Magnifying Glass: Spectacular Distance in Poe's "Man of the Crowd" and Beyond"
466:
405:
294:
255:
from 424 BC, where magnifying lenses to ignite tinder were sold in a pharmacy, and
246:
205:
194:
155:
516:
278:
139:
42:
217:
being the most iconic figure to wield it, cementing its status as an emblem of
30:"Hand lens" redirects here. For a magnifying device held close to the eye, see
496:
460:
286:
251:
151:
931:
634:
293:. Building on this foundation, in the late 1500s, two Dutch spectacle makers
245:. The earliest explicit written evidence of a magnifying device is a joke in
915:
306:
370: = (0.25 m)Ξ¦ + 1, where Ξ¦ is the optical power in
734:
566:
Sines, George; Sakellarakis, Yannis A. (Apr 1987). "Lenses in
Antiquity".
890:
17:
866:"15 BEST DIGITAL MAGNIFIERS FOR THE VISUALLY IMPAIRED | UK | March 2024"
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371:
282:
259:'s "lens", a glass globe filled with water, used to cauterize wounds. (
841:"30 Apps, Devices and Technologies for People With Vision Impairments"
610:
587:
626:
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In another innovative form, the magnifying glass can manifest as a
452:
320:
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228:
199:
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146:
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of the magnifier (again, not to be confused with optical power).
482:
emphasize the importance of inquiry and discovery in learning.
281:
described the properties of a magnifying glass in 13th-century
469:
are used as magnifiers, for example for reading printed text.
36:
822:
Williams, J. (2017). FIRE-STARTING TOOLS for Any
Situation.
891:"U+1F50E RIGHT-POINTING MAGNIFYING GLASS: π β Unicode"
397:
position. The magnifying power in this case is roughly
67:. Unsourced material may be challenged and removed.
775:(2nd ed.). Addison Wesley. pp. 186β188.
273:in 1021. After the book was translated during the
609:Sines, George; Sakellarakis, Yannis A. (1987).
8:
750:Amsel-Arieli, M. (2014). Magnifying Glass.
285:. This was followed by the development of
186:, which is often used for starting fires.
233:Diagram of a single lens magnifying glass
127:Learn how and when to remove this message
404:A typical magnifying glass might have a
708:
706:
558:
275:Latin translations of the 12th century
794:
792:
143:A pen seen through a magnifying glass
7:
766:
764:
746:
744:
65:adding citations to reliable sources
341:(this should not be confused with
27:Convex lens used to magnify images
25:
914:Sweeney, Susan Elizabeth (2003).
845:American Academy of Ophthalmology
647:Aristophanes, The Clouds, 765β70.
727:10.1097/00006123-199804000-00116
158:, posing with a magnifying glass
41:
615:American Journal of Archaeology
568:American Journal of Archaeology
389:. This is sometimes called the
325:Magnifying glass on an arm lamp
52:needs additional citations for
1:
401: = (0.25 m)Ξ¦.
208:sold as a TV-screen magnifier
683:The history of the telescope
973:
170:that is used to produce a
29:
804:search.credoreference.com
771:Hecht, Eugene (1987).
326:
234:
209:
159:
144:
611:"Lenses in Antiquity"
339:angular magnification
324:
232:
203:
150:
142:
445:Coddington magnifier
441:spherical aberration
239:Archaic Greek period
61:improve this article
437:optical aberrations
957:English inventions
800:"magnifying glass"
527:Optical microscope
327:
235:
210:
177:of an object. The
160:
145:
76:"Magnifying glass"
824:Mother Earth News
699:978-0-486-43265-6
671:Natural Questions
656:Pliny the Elder,
532:Optical telescope
337:is equivalent to
299:Zacharias Janssen
219:detective fiction
137:
136:
129:
111:
16:(Redirected from
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606:
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542:Screen magnifier
449:Hastings triplet
335:magnifying power
289:in 13th-century
164:magnifying glass
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658:Natural History
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608:
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488:
475:
473:Use as a symbol
439:, particularly
432:
415:
388:
369:
319:
311:Galileo Galilei
305:introduced the
257:Pliny the Elder
227:
215:Sherlock Holmes
191:sheet magnifier
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58:
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35:
28:
23:
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15:
12:
11:
5:
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895:Codepoints.net
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721:(4): 899β907.
702:
675:
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649:
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627:10.2307/505216
621:(2): 191β196.
601:
580:10.2307/505216
557:
556:
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529:
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507:Dome magnifier
504:
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487:
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471:
467:Fresnel lenses
463:is necessary.
431:
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414:
413:Practical uses
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386:
367:
347:near point of
318:
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303:Hans Lipperhey
271:Ibn al-Haytham
266:Book of Optics
226:
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135:
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49:
47:
40:
26:
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14:
13:
10:
9:
6:
4:
3:
2:
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870:UK Care Guide
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547:Stanhope lens
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537:Reading stone
535:
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520:
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513:
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502:Burning glass
500:
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492:Aspheric lens
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382: =
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349:accommodation
344:
343:optical power
340:
336:
332:
331:magnification
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317:Magnification
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78: β
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72:Find sources:
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898:. Retrieved
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874:. Retrieved
872:. 2023-08-30
869:
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849:. Retrieved
847:. 2020-08-14
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807:. Retrieved
803:
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755:
751:
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715:Neurosurgery
714:
682:
678:
665:
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643:
618:
614:
604:
574:(2): 191β6.
571:
567:
561:
480:
476:
465:
457:
433:
430:Alternatives
424:
420:
416:
406:focal length
403:
398:
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390:
383:
379:
375:
364:
358:
354:
346:
334:
328:
309:in 1608 and
295:Jacob Metius
264:
250:
247:Aristophanes
236:
211:
206:Fresnel lens
195:Fresnel lens
190:
188:
163:
161:
156:Ellery Queen
123:
114:
104:
97:
90:
83:
71:
59:Please help
54:verification
51:
926:(1): 3β17.
920:Poe Studies
517:Graphoscope
391:total power
279:Roger Bacon
168:convex lens
952:Magnifiers
946:Categories
900:2024-03-09
876:2024-03-10
851:2024-03-10
809:2024-03-08
758:(1), 6β7.
673:, 1.6.5β7.
553:References
522:Macro lens
497:Binoculars
461:microscope
378:Γ", where
287:eyeglasses
252:The Clouds
204:A plastic
152:Jim Hutton
87:newspapers
932:1754-6095
830:, 67β72.
635:0002-9114
596:191384703
307:telescope
243:antiquity
172:magnified
117:June 2010
18:Hand lens
669:Seneca,
486:See also
372:dioptres
735:9574655
512:Glasses
283:England
225:History
101:scholar
930:
779:
773:Optics
733:
697:
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588:505216
586:
261:Seneca
103:
96:
89:
82:
74:
592:S2CID
584:JSTOR
453:loupe
361:focus
291:Italy
184:focus
175:image
166:is a
108:JSTOR
94:books
32:Loupe
928:ISSN
777:ISBN
731:PMID
695:ISBN
687:ISBN
631:ISSN
329:The
297:and
179:lens
80:news
828:281
723:doi
623:doi
576:doi
269:by
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63:by
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