Magnification Field of View and Field Number
How eyepiece field number and objective magnification set the field of view, and why the biggest magnification is rarely the useful one.
Total Magnification Is a Product
Total magnification is the objective magnification multiplied by the eyepiece magnification, and on a zoom stereo body by the zoom setting as well. A WF10X eyepiece on a body running 0.7X to 4.5X gives 7X to 45X.
Field Number Sets What You Can See
An eyepiece marked WF10X/F.N.20 has a field number of 20. Divide the field number by the objective magnification to get the field of view in millimetres. That single division tells you whether the whole part fits in view.
Empty Magnification
Past a certain point, more magnification enlarges the image without adding detail, because the optics have already reached their resolving limit. It looks bigger and shows no more. Choosing a wider field eyepiece is usually more useful than pushing magnification higher.
Changing Eyepieces Changes Both
A WF15X or WF20X eyepiece raises magnification and narrows the field. Ranges here extend to 3.5X-270X with optional eyepieces and auxiliary objectives, but the working field at the top of that range is very small.
Where To Look In The Catalogue
8 productsMicroscope Eyepiece
Eyepieces for biological microscopes with standard DIN/JIS 23.2 mm outer diameter, available in magnifications from 2X to 25X, designed for use with existing microscope stands and digital imaging systems.
16 productsMicroscope Objective
Optical lenses designed to mount on microscope stands and provide magnification and resolution for biological, metallurgical, fluorescence and phase contrast inspection tasks.
14 productsStereo Microscope Eyepiece
Eyepieces designed for use with stereo microscopes to adjust magnification and field of view during inspection tasks. Available in multiple magnifications for compatibility with specific AMADA stereo microscope models.
Frequently Asked Questions
How do I calculate field of view?
Divide the eyepiece field number by the objective magnification. A field number of 20 with a 1X objective gives a 20mm field.
Why does my image get dimmer at high magnification?
The same light is spread over a larger image. That is normal and is why illumination becomes more important as magnification rises.
Ask Before You Order
Send the model you are considering and the task it has to do. We will confirm the fit in writing.