In this article the spotlight will be put on a tool that most modellers find useful, if not indispensable. Nearly all modellers will use some sort of magnifier sooner or later, yet they are often taken for granted. However, the correct use of magnifiers not only makes modelling easier and more enjoyable, but also can significantly improve the quality of the models.
This question may seem to be so obvious at first sight that it is not worth asking, but there is more to it than meets the eye (excuse the pun).
There are at least four benefits from using magnification.
1. The most obvious benefit is that it makes objects appear larger. This in itself is very useful. Clearly, gluing or painting very small pieces becomes much easier if they can be made to look two or three times larger.
2. The second use of a magnifier is to allow you to work closer. This is because a magnifier reduces the focal length of your sight. Depending on the natural quality of your eyesight and your age (more about age below), the closest distance that you are able to focus on an object may be a few inches from your eyes, or it may be the length of your arms.
If you can bring an object within a few inches of your nose and still see it clearly, you are very lucky. For those people who can only focus on an object that is, say, 45cm or more from their eyes, working on small objects can be difficult. Not only do objects appear very small at arm’s length, but it is difficult to manipulate a small object at that distance. It is much easier to do detail painting and sculpting when you can bring the object closer. If you want any proof of this, look at anyone threading cotton through the eye of a needle – it is so natural to hold the needle up close to your eyes because the reduced distance improves your hand to eye co-ordination.
3. The third reason for using a magnifier is that it will show up defects that you will never see with the naked eye. If you want to get a perfectly smooth surface prior to painting, or want to make sure that you have successfully filled and sanded that annoying gap, then you should examine your model under a magnifier in a good light. When you can do that and see no defects then you really do have a first class model. You might ask whether a defect matters if you cannot see it without a magnifier and there is some value to that opinion. However, there is a little bit of a perfectionist in many modellers and we like to know that our models are defect free even under the closest scrutiny.
Some defects become more obvious as the model build advances. For example, painting a model often shows up defects in the surface that were not previously noticed – how much better it would be to spot the defects before painting by examining the model under a magnifier. Furthermore, if you are entering your model in a competition then you may find that a judge will be carrying a magnifying glass, so if you have not used one he may well spot something you have missed!
4. The final reason that for using a magnifier is to reduce eye strain. Working at the limit of your vision can put strain on your eyes. With proper lighting and magnification it is possible to work longer and avoid any eye strain.
It is worth defining some common terms used with lenses and magnifiers. This will assist you in comparing different magnifiers and help you to get the magnification that you need.
Diopter – This describes how much a lens bends the light, or in other words the strength of the lens. Each diopter represents a 25% increase in power. Thus, a 4 diopter lens will increase the apparent size of an object by 100% i.e. a 2cm long object will appear to be 4cm long. The strength of spectacles and contact lenses are usually referred to in diopters. In the UK you can normally buy non-prescription reading glasses between 1.25 and 3.5 diopters. In effect, non-prescription reading glasses are simply magnifying lenses that work because they make print look bigger and also allow you to bring it closer to your eyes.
Magnification Power – This describes how much bigger an object appears to be under magnification. Each increase in magnification power equals in increase in apparent object size by 100%. For example, an object that is 4cm long normally would appear to be 10cm long under a 1.5x magnification power.
Total Power – This is similar to Magnification Power in that is describes how much bigger an object is, but in this case it relates the final size to the original size. Total Power is always one number larger than Magnification Power e.g. 2.5x Total Power is same as 1.5x Magnification Power. There can be confusion between Total Power and Magnification Power and it would be easier if everyone used the same terminology, but they don’t. Most of the time if somebody refers to a magnifier being say 2x power then they will be referring to Total Power, but it is best to check which term is being used when buying a magnifier.
Focal Length – This is the distance from the lens at which an object is perfectly in focus. The lens in our eyes is flexible and can focus over a wide range of distances. However, a fixed glass or plastic lens will only be in focus at one precise distance. Move the object closer or father away from that point and it will become increasingly blurred.
Stronger lenses have shorter focal lengths. This limits how strong a magnifier you can practically use. For example, if you have a magnifier with a Total Power of 3.5x then you will need to work within 10 cm of the lens and that may be not be enough room to comfortably wield a paint brush.
Diopters, Powers and Focal Lengths are all related as can be seen in table 1. Diopters are generally used to describe the power of reading glasses/spectacles whilst Total Power is normally used to describe the power of magnifying glasses. Table 1 allows you to work out the total magnification when using both. For example, if you are wearing 2 diopter reading glasses (equivalent to 1.5x Total Power) and also have a 1.5x power magnifier then the total magnification is 3x, or in other words, a 10cm object will appear to be 30cm long.
|Table 1: Numerical Relationships|
|Diopter||Mag Power||Total Power||Focal Length
in / cm
of 10cm object
|2||0.50||1.50||20 / 60||15.0|
|3||0.75||1.75||13.3 / 34||17.5|
|4||1.00||2.00||10 / 25||20.0|
|5||1.25||2.25||8 / 20||22.5|
|6||1.50||2.50||6.7 / 17||25.0|
|7||1.75||2.75||5.7 / 15||27.5|
|8||2.00||3.00||5 / 13||30.0|
The relationship between focal length and strength means that it is possible to calculate how strong your existing magnifier is. Put a piece of paper with text under the magnifier and move the magnifier back and forth until the text is perfectly in focus. Measure the distance between the magnifier and the paper to get the focal length and use Table 1 to determine the magnification strength.
Magnification and Lighting
There is no doubt that using a magnifier can be a big help in model making. However, even a huge amount of magnification will be of little help if you are working with poor lighting.
Getting a good light source for your work space is fundamental and should be a top priority. Daylight is ideal, but not always available, so a good substitute is an Actulite desk lamp. This has a daylight simulation bulb that shines through a polarising panel and has received very good reviews. The only downside is the price. If you are on a budget then almost any desk lamp can be fitted with a daylight simulation bulb since they come in a variety of types and sizes. A daylight simulation bulb, as it’s name suggests, produces light in a spectrum that is closer to natural daylight than normal filament or strip lighting. However, even if you are working under a standard filament or fluorescent light make sure you have plenty of it, but be aware that colours will look different when you see them in daylight.
An economical way of getting good light and magnification is to get a combined lamp and magnifier and these are covered in detail later.
Our ability to focus depends on the muscles in the human eye altering the shape of the lens. When we are young the lens starts out being very flexible, but as we get older it becomes stiffer and thus the ability to focus over wide ranges reduces.
The effect of this is that almost everyone finds it harder to focus on close objects as they get older and in order to read have to hold the paper further and further away until their arms are no longer long enough.
It is usually forty-somethings that notice this unfortunate development and the condition is known as Presbyopia. A teenager will normally be able to change the strength of the eye lens by about 14 diopters and focus as close as 7 cm, but by the age of 45 this will have dropped to 4 diopters for the average person.
Clearly, for modellers this can be a huge problem, but thankfully the answer is simple and comes in the form of a magnifying glass. This not only makes objects larger, but also reduces your focal length thus allowing you to bring the object closer and still remain in focus without straining the eyes.
Reading spectacles and contact lenses for people who are short-sighted (Myopia) or suffering from presbyopia are magnifying glasses (although prescription glasses may be cut to also alleviate other optical problems). Bi-focals and vari-focals have the lenses cut to give a range of focal lengths.
Types of Magnifier
Magnifiers come in such a wide range of shapes, types and sizes that they defy any attempt to put them into categories. However, in order to compare the advantages and disadvantages of dfferent types they have been put into groups below:
Advantages – Cheap and very portable.
Disadvantages – Can be difficult and awkward to get used to. Likely to make you a laughing stock if used in public. Only gives monocular vision. Suitable only for inspecting a model and not working for long periods.
Non-prescription reading glasses
Advantages – These allow you to have the magnification right where you need it and keep both hands free. Easily available from chemists, libraries and other shops. Can be very cheap (but check the quality).
Hand held magnifiers
Advantages – Cheap and portable, variety of sizes and strengths. Easily available from most opticians.
The magnifier is held in place by a chord that goes around the user’s neck.
Advantages – Cheap and keeps both hands free.
Disadvantages – Body movement has to be minimised to keep object in focus. Forces your hands to work close to your body.
These have a small stand with limited adjustment.
Advantages – As for hand held magnifiers
Disadvantages – Although in theory they do leave both hands free, in practice there is limited room to work under them and the stand often gets in the way so they are only really useful for specific purposes.
Advantages – gives good binocular vision just where you need it. Can be raised or lowered as needed. Available in a variety of strengths and normally the lenses are changeable. Can be worn with spectacles. Some makes have an optional accessory of a second magnifier that can be moved into view to increase magnification to one eye for close inspection.
Disadvantages – Can become uncomfortable after a while. Will generate a few laughs from the family at your expense. Relatively expensive.
Adjustable stands with or without a lamp
These are another very popular choice for modellers.
Advantages – Allows you to put the magnification where you need it and keep both hands free. Variety of lenses with some being very large and powerful giving excellent viewing.
Disadvantages – Need to have either a large heavy stand or something to clamp on to, so portability could be a problem. Relatively expensive, especially with a built in lamp (although you do get light and magnification in one implement).
How Much Should You Magnify?
This is a matter for personal choice, but a good general rule is to magnify as little as possible whilst still being able to work without straining your eyes.
You will probably find that there is not a single strength of magnification that covers all situations. Simple reading spectacles are no more than magnifiers and so many of us work under magnification all the time, but will have a separate magnification when needing to work particularly closer. It is possible to combine magnifiers, so for example looking through two magnifying glasses of 2 and 3 diopters will have the same effect as using a single 5 diopter magnifier. However, holding both magnifiers still and keeping the object in focus will be quite a challenge.
Since each person’s eyesight and way of working is unique, it is a matter of personal choice and there is no substitute for a little trial and error.
A good solution that is worth considering is to work wearing a headband magnifier and have a second magnifier on an adjustable stand that can be brought in use when extra magnification is needed to inspect work.
The ideal place to buy a magnifier is either at your local model shop or a model show. This is because you get the chance to try it out. Does that headband feel comfortable? Does that magnifier show up enough detail? These are questions that you can only answer by trying it out.
If you are thinking about buying a magnifier then take along something you are working on and trying to work on it under your prospective purchase.
Of course, you may not have access to a model shop or show, in which case there are many good sites on the internet with a wide range products.
Glass lenses are usually better quality than plastic and they don’t get scratched. However, they are heavier and more expensive.
An adjustable stand magnifier with a built in lamp may seem like a good idea and in most situations it is. However, sometimes you may want the light to come from a particular direction in order to show up any blemishes on the surface and in these cases you may find it easier to have a separate magnifier and lamp.
The desk magnifier used by the Editor of SMG has twin fluorescent tubes and gives brilliant light, but he has made a cardboard cover for one side for those situations where he only wants light from one direction. This is only safe on a low energy lamp which produces little heat and it would not be possible if the lamp was circular and went right round the magnifier. Having the light from only one direction shows up defects in the surface, or join lines that need filling.
Generally, although there are some bargains about, you will regret buying something that is poor quality. Good vision and lighting are fundamental to good modelling, so make sure your tools are up to the job.
1. Get The Light Right
Poor light will lead to poor models, it’s as simple as that.
2. Have An Eyeball Service
Your eyes are your most important tool so get them tested by an optician. A magnifier will make something look bigger, but it will not compensate for an eye defect or for a difference between two eyes. You need to check that using magnification is not hiding some underlying defect with your eyes.
3. Treat Your Eyes With Respect
The human eye was never designed for the long periods of extreme close work that we modellers demand. Rest your eyes for at least a few minutes every hour and try to look at distant objects. Working somewhere you can occasionally glance out of a window is ideal.
4. A Magnifier Is Not An Eye Protector
If you use a magnifier you will be working close to your subject possibly with sharp tools. It may not be practical to wear eye protection and use a magnifier, but be sensible. SMG does not recommend using a power tool under a magnifier because of the danger of bringing the power tool too close for safety.
5. Don’t Let It Spoil Your Fun
Let us not forget that modelling is a hobby and we should be enjoying it. Using a magnifier can increase that enjoyment by making it easier and getting better results. However, don’t feel that if you must spend hundreds of hours straining under 10X magnification to get a model that is worthy. If your model looks good with the naked eye then it is good!