Optical Information Datasheet
How to Calibrate a Microscope to take Accurate Measurements
If you want to make measurements on your microscope you will need to calibrate it. The Cambridge Optics has the largest range of specialist microscopy calibration scales backed by expert advice.
To calibrate a Microscope Camera System or a Microscope Eyepiece Reticle/Scale you will need a Micrometer Slide if you have a metallurgical microscope you will need a reflective Micrometer Slide
Micrometer Slides (also known as Stage Graticules, Stage Micrometers and Calibration Slides) are generally standard microscope slides with scales & patterns etched or printed on them.
The scales come in a huge variety of sizes, subdivision accuracies and patterns. The slides are typically 76x25mm standard size and made of glass (for bottom illuminated microscopes) or of polished metal (for reflected light materials/metallurgical microscopes). If you cannot find anything here we can obtain it for you, please ask. These slides are used to calibrate microscopes so measurements can be made.
To make measurements or to perform particle sizing on your microscope without a suitable Microscope Camera System you will need an Eyepiece Reticle as well as a Micrometer Slide
Eyepiece Reticles are similar scales placed in eyepieces. The reticles are available not only as scales of different sizes and orientations but also in additional patterns such as counting grids and particle sizes. Reticles come in a variety of sizes dependant on the eyepiece diameter - not all eyepieces can have them fitted. It is best usually to use a specialist 'focussing' eyepiece to ensure that the subject and the scale are both in focus at the same time. Fitting to existing eyepieces requires the presence of a retaining ring and an absolutely precise measurement of the inner diameter of the eyepiece where the reticle is to be fitted. Many of the Reticles we show are already pre-fitted into specialist focussing eyepieces, these are suitable for GX Microscopes microscopes, any monocular microscopes and other microscopes if supplied with a matching standard eyepiece for binocular viewing.
To perform counting of objects such as cells on your microscope without a suitable Microscope Camera System you will need either:
- an Eyepiece Reticle with a counting grid and Micrometer Slide (so the grid can be calibrated) or
- a specialist Micrometer Slide with a Counting Grid and usually a special coverglass.
Please ask for advice, we can provide almost any eyepiece reticle of any size
Microscope Eyepiece Reticles
Microscope Eyepiece Reticles (also known as eyepiece micrometers, eyepiece scales, counting eyepieces and eyepiece graticules) consist of a glass lens with a scale, grid or pattern which fits into the inside of an eyepiece of a microscope to aid measurement, particle sizing and counting.
This diagram shows where a reticle is fitted in a standard eyepiece:
Ideally the eyepiece into which the reticle is to be fitted should be a special 'focussing type'. This is to ensure that the scale is in focus at the same time as the subject. As the majority of microscopes are not fitted with focussing eyepieces we have listed here several focussing eyepieces with reticles pre-fitted which are suitable for use with GX Microscopes.
To supply a reticle you need to firstly ensure that your eyepiece is 'reticle receptive', that means that there is a thread on the underside of the eyepiece where the reticle fits. It is also required that the thread has already a thin reticle retaining ring which has to be unscrewed, the reticle inserted, and then screwed back onto the reticle (see pictures right). Secondly, we need to know precisely the inner diameter of the tube into which the reticle is to fit. If you are able to provide that information then we can easily supply you with the reticle.
Please note that because there is such a huge variety of tube diameters and available patterns each reticle is specially made and is most carefully wrapped in a dust-free environment, this prolongs delivery times and means that it is a 'special', will be 'unsterile' once opened and therefore we regret that are unable to give refunds if it cannot be fitted.
If you have a current model microscope from a major manufacturer such as Olympus or Leica and if you can give us the inner diameter of the eyepiece we will probably be able to source a microscope manufacturer's eyepiece reticle. For older models we (and you) can obtain almost no support from the major manufacturers for this sort of query. If you do not have a manufacturer's part number and in the absence of any manufacturer's support, the amount of time it would take to track down the correct item makes it grossly uneconomic so, in those circumstances, we regret that we are unable to supply the original manufacturer's eyepiece reticles for non-current models.
Please select the reticle by the pattern or scale you need, the general size range of the scale and then advise us of the inner diameter of your eyepiece.
Microscope Micrometer Slides
If you want to make measurements on your microscope you will need to calibrate it, for this you need a Micrometer Slide
To calibrate a Microscope Camera System or a Microscope Eyepiece Reticle/Scale you will need a Micrometer Slide if you have a metallurgical microscope you will need a reflective Micrometer Slide
Micrometer Slides (also known as Stage Graticules, Stage Micrometers and Calibration Slides) are generally standard microscope slides with scales & patterns etched or printed on them.
The scales come in a huge variety of sizes, subdivision accuracies and patterns. The slides are typically 76x25mm standard size and made of glass (for bottom illuminated microscopes) or of polished metal (for reflected light materials/metallurgical microscopes). If you cannot find anything here we can obtain it for you, please ask. These slides are used to calibrate microscopes so measurements can be made.