Final Magnification
The final magnification is the ratio of the size of the image divided by the size of the actual tissue. Think of it as the number of times larger the tissue must be made to make it the same size as the image. The final magnification describes the level of detail that is visible in an image. A number of factors contribute to the final magnification including the objective lens, the oculars, the monitor, and the video camera. The combined result of all of these factors is the final magnification.
Two calibration steps are necessary to determine the final magnification: monitor calibration, and lens calibration.
- Monitor calibration determines the size of the image in microns per pixel.
- Lens calibration determines the physical size of a pixel.
Performing a final magnification calibration
The final magnification monitor calibration determines the size of a pixel on the computer’s monitor. You need a calibration transparency or ruler marked in centimeters to calibrate the monitor.
- Click Tools>Final Magnification then click OK.
- A grid with an anchor is displayed on the screen. Place a grid transparency or a metric ruler (with cm) over the screen grid.
- Move and re-size the screen grid to align with the transparency or ruler.
- Place the cursor over the anchor and drag to move the entire grid.
- Move the cursor over a horizontal line until the crosshair changes to a two-headed arrow.
- Drag the horizontal line until the grid matches the transparency or ruler.
- Move the cursor over a vertical line until the crosshair changes to a two-headed arrow.
- Drag the vertical line until the grid matches the transparency or ruler.
- When transparency (or ruler) and screen grid are aligned, right-click and select:
- Accept Final Magnification: Uses the final grid settings as the monitor calibration.
- Undo Last grid Change: Select to undo the last action on the grid.
- Quit And Discard Changes To Final Magnification: All changes are canceled.
- To display the final magnification, select Tools>Edit Lens.
- Select the lens that was calibrated and click Edit.
- Stereo Investigator displays the final magnification in the Edit Lens Parameters window.
Also see Creating a lens, Edit Lens, Create a new lens/Edit a lens: Parameters
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