Microscope magnification explained

The total magnification formula

Eyepiece magnification × objective magnification = total magnification. For example, a 10X eyepiece paired with a 4X objective provides 40X. The same eyepiece with a 40X objective provides 400X.

Magnification is not the same as resolution

Magnification makes an image appear larger. Resolution is the ability to distinguish nearby details. If the objective, specimen, lighting, focus, or contrast cannot resolve more information, additional enlargement may produce a larger but softer image—sometimes called empty magnification.

Why high power is harder to use

As objective power increases, the visible field becomes smaller and working distance typically decreases. The specimen must be centered before switching objectives, illumination often needs adjustment, and focus movements must be finer.

A reliable focusing workflow

1. Place and secure the slide.
2. Select the lowest-power objective.
3. Center the feature you want to observe.
4. Use coarse focus to find the image, then fine focus to sharpen it.
5. Move to the next objective and use fine focus.
6. Repeat one step at a time.

About the 100X oil-immersion objective

Use immersion oil only with an objective and procedure specifically designed for it. Follow the product instructions, keep oil away from dry objectives, and clean the oil-immersion objective promptly with appropriate lens material after use.

Never force a focus control or allow an objective to strike a slide. If the image disappears, return to low power, re-center, and focus again.