A Barlow lens is an auxiliary optical lens used with compatible microscope systems to change effective magnification. Depending on its power, it can increase or reduce magnification, which also changes field of view and working distance.
[note] Takmly microscope is a handheld digital magnifying camera rather than a conventional stereo microscope. Do not assume a Barlow lens will fit or focus correctly unless the specific microscope and lens arrangement are compatible. [/note]What a Barlow Lens Changes
[reference] Title: Magnification Text: A Barlow lens changes the effective magnification by its stated multiplier when used with a compatible optical system. Title: Field of View Text: Higher effective magnification shows a smaller area of the sample, while lower effective magnification shows a larger area. Title: Working Distance Text: Higher magnification generally requires the lens to work closer to the sample. Lower magnification can provide more space between the lens and sample. [/reference]Magnification and Viewing Area
Magnification, field of view, and working distance have an inverse relationship. Increasing magnification usually reduces the visible area and the available space between the lens and sample. Reducing magnification generally increases both.
More magnification is not always better. A wider field of view can make it easier to locate features on a larger sample, while additional working distance can provide more room for positioning or using small tools around the sample.
[compare] Higher effective magnification | Shows a smaller field of view and generally provides less working distance. Lower effective magnification | Shows a larger field of view and generally provides more working distance. [/compare]Barlow Lens Multipliers
On compatible optical microscopes, total magnification is calculated by multiplying the magnifying elements in the optical path.
- A 10X eyepiece with an objective set to 1.0X produces 10X total magnification.
- Adding a 2.0X Barlow lens to that compatible setup changes the total to 20X.
- Using a 0.5X Barlow lens instead changes the total to 5X.
A higher-power Barlow can therefore increase image magnification, while a lower-power auxiliary lens can reduce magnification and provide a wider viewing area.
[warning] Do not stack higher- and lower-power Barlow lenses simply to cancel their magnification effects. On optical microscope systems, stacking auxiliary lenses can interfere with focusing and may not produce a usable image. [/warning]Using This Information with Takmly microscope
The examples above describe the behavior of Barlow lenses on microscope systems designed to accept auxiliary optics. Takmly microscope displays its close-up camera image on a separate screen, so conventional eyepiece-and-objective calculations should not be treated as guaranteed accessory behavior for this product.
- Check that an auxiliary lens is physically and optically compatible before considering it for the microscope.
- Do not assume that a 0.5X or 2.0X Barlow will produce the same result as it would on a stereo microscope.
- Consider field of view and working distance as well as magnification when deciding what viewing arrangement is useful for a sample.
- If the normal microscope setup already provides the required view, an additional optical lens may not be necessary.