Digital video microscopes utilize a camera to record and capture images. Traditional microscopes perform visual inspection with an eyepiece, but digital video microscopes achieve higher resolution and higher precision than what is typically seen with the human eye. There are numerous applications and setups for these microscopes, ranging from the use of standard DIN and JIS objectives to advanced infinity-corrected objectives. Infinity-corrected digital video microscopes can be quite complex to assemble; however, knowing which microscope components to use and how they work together makes the process accessible for biological, industrial, and any other inspection applications.
To get started, consider the basic differences between finite-conjugate microscope objectives and their infinity-corrected counterparts. Finite-conjugate objectives, such as those found in traditional laboratory or university microscopes, focus light directly onto a sensor or eyepiece. Typically, these objectives are achromatic and only correct for chromatic aberration at two wavelengths: red and blue. On the other hand, infinity-corrected objectives require an additional imaging component, a tube lens, to focus light onto a sensor or eyepiece, but also allow access to the parallel optical plane. By accessing the optical plane, optics for attenuating or filtering light, beamsplitters for in-line illumination, or additional imaging components can be incorporated into the setup. Typically, these optics are apochromatic and correct for spherical and chromatic aberration at three wavelengths (blue, yellow, and red), and also have a much higher numerical aperture for improved light levels and contrast.
FOUR-COMPONENT DIGITAL VIDEO MICROSCOPE COMPONENT
When assembling a microscopy system with an infinity-corrected objective, there are two setups to incorporate a camera for live video feed and still frame capture. Depending on the simplicity of the setup, one can quickly and easily construct a digital video microscope component with magnification as high as 200X. The most straightforward setup involves only four components: a camera, extension tube, tube lens, and microscope objective
The four-component system enables the easy setup of a direct video microscope with high magnification and either high resolution or high frame rate. For example, one can achieve an extremely high resolution image with a pixel count of 3840 x 2748 (10.5MP) at a frame rate of 3 frames per second (fps).
The microscope components are threaded together and connected, with a full system length just under 267mm (10.5") and optimized for 10X magnification. The digital video microscope component length will change slightly depending on the magnification power of the objective in place. A good rule of thumb is: The smaller the objective magnification, the shorter the system length.
