How do magnifiers work?
Magnifiers work by bending light rays to produce an image of the object that is larger than life. The more the surface of the lens is curved, the more the light is bent and the greater the magnification. The degree of magnification is then determined by the curvature of the lens surface. Greater curvature limits the lens size, which means that higher powered magnifiers are going to be smaller.

10x or less is a good choice to start with for most pest scouting. Once a pest is located, a larger power lens may come in handy. With practice and increasing skill in scouting, you will eventually want to equip yourself with a wider range of magnifiers to be able to complete nearly all of your sampling and identification tasks in the field.

What different types of magnifiers are there?
There are many forms of magnifiers; loupes, linen testers, watchmaker's loupes, aspheric, lighted, folding pocket, etc. One style is not necessarily better than another. It depends on the style of magnifier you feel comfortable using.

What are the different type of lens systems?
When using magnifiers, be aware of distortion, and chromatic or spherical aberration errors that can occur. Distortion is a defect in a lens where images of straight lines appear curved. Chromatic aberration errors are when the lens cannot focus light of different colors at a single point, causing a blue-red image. Spherical aberration errors cause rays to focus at different distances.

Different types of lens systems offer varying levels of correction for these problems. The simplest type of lens is the single aspheric lens. This lens is designed for small powered magnification because it is one lens. The lens has a series of different curves on the surface for sharper focus over the entire surface.

Spaced Doublet is two lenses with air space in between them. This lens system is inexpensive, but does not offer much distortion or color correction.

Coddington Lens are made of a single lens with a grooved diaphragm around the circumference. This groove allows for sharp images at higher magnifications.

Cemented Triplet is the last type of lens, also called a Hastings. The Hastings lens is three lenses cemented together, providing the sharpest color-corrected image.

What is the proper way to use a magnifier?
To use a loupe, hold the lens close to your eye and move the object you are looking at close until it's in focus. For linen testers, simply place the magnifier on top of the object and move your head closer to the lens for larger viewing.

Hands-free Magnifier Reduces Eye Strain
Have you experienced headaches or eye strain after extensive monitoring for small insects or plant diseases?

Does the use of a hand lens during scouting make it difficult to manipulate samples with your hands?

Repetitive sampling and scouting are key components of IPM. But juggling a hand lens in addition to a sample can be inconvenient and time consuming. One solution that allows you the freedom to work with your hands plus reduce eye strain is the OptiVisor® magnifier. With a magnification power of 3.5x and a focal distance of four inches, the OptiVisor® is a good tool for scanning large areas for insects, eggs, mites and plant disease.

The OptiVisor® is mounted to an adjustable headband and can be tilted up when you're not using it. An optional OptiLoupe, an attachable lens that adds 2.5x power to one eye, is also available. This combination creates a powerful monitoring tool. You can scan large areas with the OptiVisor®, then swing the OptiLoupe into place to "zoom in" when more detailed examination is necessary.

When selecting a magnifier, keep in mind that:

• Magnification power is described as "x". For example, the OptiVisor® is rated at 3.5x. That lets you observe an object 3.5 times larger than life.
• Your viewing area decreases in size as magnification power increases.

For more information on these products, please contact GEMPLER'S Technical Service Department by phone at 1-800-874-4755, or E-mail at techserv@gemplers.com.