Why are Sheet Magnifiers called Fresnel Lenses?

Celebrating the life-saving lens invented by Augustin-Jean Fresnel

One of the most frequent questions we get asked is: ‘what is the biggest magnifier I can buy?’ We have hand-held magnifying glasses up to 5-inches in diameter but that’s about as big as a normal magnifier can go. If you need something larger, then you will need to go for a fresnel lens, named after the French physicist who invented them – Auguste-Jean Fresnel.

Fresnel lenses are made from flat plastic sheets, comprising of a series of concentric rings, which gather and direct light towards the centre of the lens. They allow magnifier manufacturers to construct lighter-weight lenses over larger viewing areas, though it is fair to say that the optical quality is not as good as on a conventional lens.

They are very popular though, with a number of advantages for uses

  • Lightweight magnifying lens – normally made from acrylic or PVC
  • Large viewing area –
  • Inexpensive – cheaper than standard magnifiers
  • Different sizes – from credit card to A4 and above
  • Flat, easy to store

When you look through one of these seemingly simple credit card or full page magnifying sheets, it seems amazing to think that the real reason for the invention came about from a need to save lives at sea.

A Life-saving Lens for Lighthouses

From around the17th century, maritime traffic increased as a means of carrying goods between nations. Lighthouses were critical for helping ships navigate their way along rocky coastlines. Unfortunately nobody had come up with an adequate way of making the light visible from a distance far enough away from treacherous rocks – often with fatal consequences.

For thousands of years lighthouses had just used open flames to warn sailors but these were ineffective in wind or rain. In the 1690s the glass lantern room was invented and first used with candles at Eddystone Lighthouse off Cornwall, to create brighter, more protected light; whilst mirrors were used elsewhere as crude reflectors to direct the light.

Despite these improvements shipwrecks continued because none of them could retain enough of the light to alert ships adequately of any danger. The number of shipwrecks reached such a level that the French government set up a commission with a financial prizes for anyone who could come up with a solution.

Augustin-Jean Fresnel (1788-1827)

The breakthrough came through the work of Augustin-Jean Fresnel, a 19th century physicist, born in Broglie, France in 1788. He was brought up in a strict Catholic household, and received his early education from his parents. As a child he was initially regarded as a slow learner, who could barely read by the age of 8, and showed little aptitude for languages or tests of memory.

Despite all this his boyhood friends regarded him as something of a genius, who would spend hours on ways to increase the power of popguns and bows, gradually leading him to an interest in mathematics and a university education studying engineering.

After graduating he worked in various French government departments until finding himself cast out following the return of Napoleon from exile in Elba in 1815.

By this time Fresnel had started conducting his own separate scientific studies into the behaviour of light, calculating different formulas to show how light could change direction, or refract, as it passed through prisms made from glass. Instead of creating one gigantic lens, Fresnel worked with leading glassmakers of the day to produce a thinner, lighter and more efficient lens, made up from multiple panels and prisms to retain and re-direct virtually all the available light.

The first Fresnel lens was installed in 1822 in the Cardovan Tower lighthouse on France’s Gironde River. With a large lamp in the centre, Fresnel’s lighthouse lens could gather, magnify and project the light for more than 20 miles away. In the following years many more European and US lighthouses had fresnel lenses installed, doubtless saving the lives of thousands of sailors.

Thanks to Fresnel, the world gained a greater understanding of the behaviour of light, and his work led to a major breakthrough for lighthouses and maritime safety.

Fresnel’s Lenses – the legacy

Augustin-Jean Fresnel never lived long enough to see how successful his studies proved to be. He did not enjoy good health during much of his lifetime and was only 39 when he died in July 1827. In the century after his death some 10,000 lights with fresnel lens were installed in lighthouses and other buildings across the world.

He is buried at the famous Pere-Lachaise cemetery in Paris. Once you have taken in the more famous graves of other ‘residents’ – Oscar Wilde, Edith Piaf, Jim Morrison, Frederic Chopin, Yves Montand, Simone Signoret, Camille Pissaro – it’s worth exploring a little further to find Fresnel’s tombstone.

For someone whose invention has made its way to everyday magnifying vision aids, it seems ironic that his grave is somewhat hard to find. It is not well marked and even the original inscription on his tombstone has been eroded. You can just still make out the remaining words ‘To the memory of Augustin Jean Fresnel, member of the Institute of France“.

Where To Buy Fresnel Lenses Today

Magnifico offers the biggest selection of fresnel lenses in the UK. They are very popular, with several variations – card, bookmark, A6, A4, some with frame, some not, flexible sheet magnifiers and rigid page options.

In case you were wondering, ‘fresnel’ being French, has a silent ‘s’ in the middle so the pronunciation is ‘fre-nel’ (actually ‘fray-nel’ if you wish to go for the full French accent).

Cimetière du Père Lachaise, 16 rue du Repos,75020 Paris 
Tel.. +33 (0) 1 55 25 82 10

Subway – Père Lachaise, Philippe AugusteBus – 26, 54, 60, 61, 64, 69, 76, 102, La Traverse de Charonne


20 Things You Can Do With A Magnifying Glass

Be inspired – so many tasks, jobs and hobbies are made more enjoyable with a magnifier.

Magnifico (The Magnifier Company) has been around since 1999. In that time we must have had every possible enquiry going about magnifying glasses, helping customers with queries on subjects that are often brand new to us (pigeon eye anyone?).

Of course everyone knows that magnifiers are great for reading books, enlarging stamps, studying maps and enlarging tiny insects but that’s just the start of it. We know too that they are invaluable magnifying aids for the blind and for those with impaired or low vision. We’ve also encountered many professions that use magnifiers for their daily work. Archivists, science lab technicians, production line inspectors, crime scene detectives and beauty therapists could not manage without them.

Over the past 20 years barely a week has gone by without someone sending us a new query about a magnifying glass. In many cases they are for usage requirements that are completely new to us. Here’s a selection covering 20 things that you can do with a magnifying glass – some well known, others more unusual. Please let us know what you use your magnifier for – perhaps we’ll add your use to a future list.

Make do and mend
So many of us now are looking to save the planet by recycling the old instead of replacing with new. The BBC series The Repair Shop has shown the way but our eyes also need a little TLC. A magnifier can take away the strain, leaving hands and eyes free to concentrate on the task to hand.

Electronics repairs
Vintage radios, printed circuit boards, old phones and other electronic items have many minuscule components that the naked eye cannot fully see. With a fixed lens over them, you can see the detail and fine tune even the tiniest part.

Complete a puzzle
Those fiendish jigsaw designers just have to try and make each puzzle more difficult. They know that making two pieces almost exactly the same is part of the challenge. A decent stand magnifier gives you a fighting chance of being able to tell them apart. Now there are only 998 pieces to go.

Learn about the natural world
It’s fair to say that you probably won’t see a silverback gorilla in your garden but there’s plenty to marvel at so close to home. Ants, beetles and bugs of all kind are truly amazing when you look at them under a magnifying lens. Share the experience with a child and give them a love of nature for the rest of their lives. 

Win at a quiz
There’s nearly always a picture round at a quiz – normally something like ‘Celebrities as Babies’. It’s not just the winning that counts. One way to impress your fellow team members is to pull out a credit card magnifier to help identify the famous faces.

Prospect for gold
If you ever take a ring to be valued, the jeweller will inspect it closely through a powerful magnifying loupe to reveal the hallmark. The hallmark tells you the purity of precious metal in the item. Gold, silver, platinum and palladium must all be hallmarked by UK law. 

Eat more healthily
magnifier-to-check-food-packagingFood manufacturers are trying to reduce packaging just as consumers demand more information. Calorie counts, allergy warnings, artificial flavourings and recipes can all influence the buying decision but the text is so small that you often need a magnifier to see it. 

Train your eyes
If you have had glaucoma, advanced macular degeneration or cataracts, then your optometrist might suggest a magnifying glass as a way to ‘train’ your eyes to adjust. We can assist but if you think you have any issue with your vision, don’t delay – go to an eye specialist straight away to get proper professional advice. 

Bring back old memories
Even In a digital age, nothing beats a magnifying glass for the sheer joy of looking at boxes or albums full of photos. The tiniest detail, a sign revealed or a face enlarged, can instantly transport you back to ‘the good old days’.

Manage your finances
Perhaps you are about to buy, buy, buy on the stock market, or you simply need to check an old premium bond certificate, the numbers may be too small for the naked eye. Bar magnifiers that rest on the page have the added benefit of helping you keep your place.

Research your family history
Genealogy is a popular and fascinating hobby but occasionally it’s a test of endurance. Researching family histories through  ancient documents and historic texts can take a while. An endless supply of coffee, a decent notebook and a good-sized magnifier would seem to be three sensible tools to help you get started.

Read the meter
Magnifiers are handy to have for all manner of mundane household tasks – from highlighting gas and electricity readings, to checking small print on insurance documents or gadget instructions, through  to removing a splinter when a DIY or garden job goes wrong.

Take the right tablets
If you are on medication, or maybe know someone else who has to take pills on a regular basis, it’s not a bad idea to keep a magnifier in the medicine cupboard. Labels and instructions are so small that anything making them easier to follow surely must be welcome.

Let’s get crafty
Stand magnifiers, magnifying lamps, head or round-the-neck magnifiers all have one thing in common: they keep your hands free for sewing, model-making, painting or any other art and craft task.

Solve a crime 
Sherlock Holmes was not the only detective to use a magnifier. The classic magnifying glass still forms part of an essential crime scene field kit, along with fingerprinting equipment, plastic bags and tweezers.

Study ancient maps
Whether your interest is in the Lost City of the Incas or what happened to the old village hall, poring over old maps is an absorbing pastime, but one which certainly benefits from having details made larger.

Help people with reading difficulties
We have dome and bar magnifiers with reading lines that can help children with dyslexia to more easily identify and highlight words when reading.

Manage your production line
Magnifying lamps are used widely in manufacturing environments for production control, quality inspection and component testing. Our industrial-strength lamps feature large lenses, with adjustable arms, bright LED or daylight illumination, bench clamps, wall mounted and floor. standing fittings.

Swallow a dictionary
Find or check a meaning of a word, look up a reference or a date, find an alternative phrase or meaning, even discover how to say something in another language. There aren’t as many things to do with a magnifier as there are words in a dictionary but having a magnifier to hand when you’re looking certainly enables you to find way you are looking for more quickly.

Promote your business
Magnifiers overprinted with your logo, brand or message make great low-cost giveaways for organisations of all sizes. We have more than 20 years supplying magnifying glasses as bespoke promotional gifts. Our magnifiers have been commissioned by marketing teams for Mission Impossible, Royal Bank of Scotland, the House of Lords as well as countless other great causes, companies and campaigns over the years.


ICU! Best Magnifiers for Hospitals.

Which Magnifiers are best for Hospitals and ICUs?

Never in a million years did we think we’d be writing like this about magnifiers for hospitals. Even in the current coronavirus pandemic we thought we’d be recommending magnifying glasses for hobbies in the home. Reading, crosswords, jigsaws and recipes to name but a few.

Or we thought we’d be making suggestions for people needing magnification for other, less interesting tasks around the house. Like reviewing insurance cover, checking employment small print, reading instruction manuals or looking at medicine bottles. All of these are ones where a magnifier might come in handy.

NHS request for magnifiers

Then very late last night we received this email:

‘Hello – I’m a nurse working on critical care at the Northern General Hospital in Sheffield. Our staff are struggling wearing glasses with the PPE. I am looking at the possibility of having a magnifying  glass at every bed space. It would have to be:

  1. Fairly cheap, else it’s likely to go missing (it’s likely to go missing anyway – we lose everything).
  2. Easy to clean between patients.
  3. Big enough to read charts.

I also don’t know what magnification would be best. We have 14 beds on the main unit. Can you help please?

Thank you, L’

Having responded to the enquiry, we are pleased to share here our recommendations. Using price, hygiene and size as a starting point please find our suggestions below.

Magnifiers for critical care

Hygiene in hospitals really is critical, perhaps nowhere more so than in an ICU (Intensive Care Unit). Finding magnifiers that are suitable for use in such environments is not as simple as it sounds.

The main reason for this is that any device used in a hospital must be kept clean. Ideally this means that the whole magnifier is made from the same piece of material. Not an easy task because most magnifiers have several component parts. Lenses and handles are normally made from different materials. Then you have lens rims, switches, battery housings, screw fittings, adjustable arms. The list goes on. More components mean more opportunities for tiny particles of dust and other matter to gather, making cleaning harder and more time-consuming.

Our recommendation is that hospitals use magnifiers made out of as few component parts as possible. So we are suggesting two magnifiers made from just a single piece of plastic, thus making them more hygienic than other magnifying glasses.

Windsor Magnifying Glass – the best magnifier for hospitals

Windsor Magnifying Glass For Reading Patient Charts and Medical Reports
  • Made from one piece transparent plastic
  • Easy clean, dirt spots immediately visible
  • Three lens sizes: 47mm, 70mm, 98mm diameter
  • Hole in handle for hanging cord or string

The handheld COIL Windsor Magnifier is made from a single piece of transparent molded plastic. Ideal for use in sterile environments, it is easy to clean. No part of it allows microscopic bacteria to gather. Being made from all-clear plastic, even the naked eye can see dust or dirt particles needing to be removed. Hospital ICUs, Labs, Sterilisation and Disinfection units de-contaminate and process thousands of used medical devices. Receiving and distributing sundry items all day long is commonplace in hospital wards, theatres and clinics. Making sure the contents are clean takes up precious minutes. Simple magnifiers like the Windsor can be wiped clean in seconds.


As instruments and devices come back in to the units for processing they all have to be tracked and then tagged before they can be issued safely again. Imagine what a strain on the eyes it must be to read and register those tags – and that’s where a magnifying glass becomes very useful. The COIL Windsor offers different options to help medical staff check numbers and records.

Three different sizes

Many hospitals in the UK cover such magnification tasks by taking two, or even all three of the different Windsor sizes. The strongest, most powerful one is the little 48mm-diameter version, which magnifies up to 4.4 times original size. The 70mm one magnifies 2.6x, while the larger 98mm version makes everything look just over twice as big (2.3x). Go for the smallest one for the most powerful magnification, or choose the biggest if you need a comfortable view over a larger area.

Windsor magnifying glasses are made from tough, shatterproof plastic so they are likely to survive the occasional drop on a hard hospital floor. A small hole drilled into the handle enables the Windsor to be hung on a hook or even threaded with a cord of some kind so that they can always be kept around a hospital staff member’s body.

On wards and up wards? Extra Strong Magnifier Sheet –  fresnel magnifying lens

Fresnel lens magnifying sheets allow viewing of larger areas
  • Made from single sheet plastic
  • Easy wipe-clean
  • Durable – 2mm thick
  • A4 size, 2x magnification

Small text on patient charts and graphs puts a strain on the eyes. Viewing large areas of data can be a chore. This large magnifying sheet covers an area up to A4 and magnifies text to twice its original size (two times/2x magnification). It is made from a single piece of rigid optical-grade acrylic, which can be wiped clean. Extra thin concentric lines on the surface of the lens improve viewing clarity, especially around the centre. The plastic is 2mm thick, allowing it to be held over the subject matter with just one hand (this one does not ‘flex’ like fresnel lenses made from thinner material – normally PVC).

How do fresnel lenses work?

Fresnel lenses are made up of hundreds of concentric grooves, etched onto a flat surface, to gather and direct light towards the centre. These grooves are easier to produce on plastic surfaces than glass ones, often over a much larger area than exists within the capability of a normal magnifying lens. Hence they are helpful when a thin, lightweight magnifier is required, perhaps to view a bigger subject or a large block of text.

The overall image quality is rarely as good as that from a conventional glass or plastic lens but in many applications a fresnel lens is a cheaper option, perfectly adequate for general low-level magnification requirements. We have had our Extra Strong Magnifier Sheet in our range since we began and the improved viewing quality from its thicker lens shows through time and again.

More magnifying solutions

Away from ICUs, other hospital departments also use magnifiers frequently. Choose an illuminated hand-held magnifier for a little extra light when checking patient files. Try a desk model if you need to keep your hands free. Use a magnifying lamp in a lab if you need extra magnification and strong white light.

Fresnel lenses are always popular, cost very little, and come in different sizes. Most are made from thin, flexible PVC. Any of these would also be suitable for use in a medical environment. Popular credit card size mini-lens magnifiers can be kept to hand in a pocket or even on a clipboard.

credit-card magnifier
Card magnifiers like this are the size of a credit card

Do you work for the NHS?

If you are working in a frontline NHS department and need magnifiers, please get in touch with us. We’re only too happy to be given a chance to help.

Take care and stay safe.



Welcome to our blog – In the Loupe. No, it’s not a spelling mistake. We meant loupe, not loop. We didn’t do it because we were worried about confusion with the BBC TV comedy of the same name. Jewellers know what loupes are, and there is sure to be information on this web site about them soon.

We’ll be using this Blog to tell you everything we can that’s related to magnifiers, magnifying glasses, lamps, fresnel lenses, linen testers, low vision and loupes of course.

Do feel free to send in any ideas or questions. We’re only to happy to take a closer look…