A microscope reveals an exciting and strange world that includes diatoms, radiolarians, crystals, ciliates, tardigrades, rotifers, amoeba, bacteria, pollen, and a wide variety of animal and plant cells. Microscopes are important in research, industry and education and scientists communicate their discoveries in research papers supported with photomicrographs. Hobbyists like to share their observations with their friends and family on social media, forums and anyone that is not fortunate enough to own a microscope. Taking pictures through a microscope is easier than ever and in this article I describe some methods to use digital cameras to take pictures with a microscope.

Dedicated Microscope Cameras

Microscope companies like Motic make dedicated digital cameras for photomicrography that capture photos and movies. Software that comes with these cameras may also enable a person to make measurements from the photos, add scale bars, or modify the image before taking the picture. These cameras are usually tethered to a computer by a universal serial bus (USB) cord which can control the shutter and permits viewing the images seen through the microscope on the computer monitor. The images can also be projected onto a large screen with an LCD (liquid crystal display) projector for teaching or presentations.

Dedicated cameras for photomicrography attach to a C-mount of a microscope usually positioned on the trinocular head or they can be attached to a special eyepiece that can be inserted into any monocular, binocular or trinocular tube. A C-mount is a type of lens mount found on 16 mm movie cameras and microscope phototubes. C-mount lenses provide a male thread which mates with a female thread on the camera. With the addition of special adapters these cameras and associated eyepieces fit into wider stereo microscope ocular tubes. C-mount cameras may come with eyepieces (1X, 0.5X, or 0.41X). Lower magnification eyepieces illuminate more of the sensor area. With a 1X eyepiece sometimes less than 50% of the sensor is illuminated compared to what you see through the microscope eyepiece. If the magnification of the C mount eyepiece is too low however you will see a vignette around the edge of the screen. Dedicated digital cameras will generally cost more for less resolution than a DSLR, but they may allow more precise control and come with specialized software for image analysis.

The image quality is suitable for the internet, quality control inspections or anywhere where small images are acceptable. A 3MP camera is limited to making prints about 8 x 10 inches in size.

Most sensors used in dedicated microscope cameras are small and similar in size to those found in cell phones. Dedicated cameras for photomicrography offer between 1 to 20 MP – in general more megapixels are better. Some dedicated microscope cameras come with a larger 1-inch size sensor and 20 MP costing $800 or more and allow enlargements 10 x 15 inches or larger.

In general cameras with larger sensors tend to produce higher quality images with lower digital noise. Some of the dedicated cameras provide black and white images and some are specialized and use cooled sensors to reduce digital noise common in low light microscopy (e.g. polarization and fluorescence microscopy). Dedicated microscope cameras also have silent shutters that cause virtually no vibration during exposure.

The small size and weight of dedicated cameras and an attached eyepiece means they can be inserted into any binocular or monocular tube without putting any strain on the microscope which is an advantage if the microscope does not have a trinocular head.

Another advantage of dedicated microscope cameras is that a computer used in combination with software permits modifications to the digital image before taking a picture. Software associated with some of these cameras can also facilitate pre and post processing as well as the ability to quantify data in the images.

Most dedicated microscope cameras save their images as .jpg, or .tif files. A few cameras may use proprietary image file formats that require the manufacturer’s software for viewing and analysis. These cameras also require a computer in most instances to take pictures though some have an exposure button on the camera and can store digital images onto an SD (secure digital) memory card.

Disadvantages of dedicated cameras are that they use small sensors (most are less than one inch), and many have a low number of megapixels (10 MP or less) which limits the amount of fine detail that can be seen and the amount of enlargement possible. Scientists rarely need images larger than 8 x 10 inches for publication and for this reason dedicated cameras for photomicrography are widely used in research.

Posted by Motic America on July 06, 2020