Dedicated microscope digital still cameras are among the best priced microscope digital cameras nowadays. Dedicated microscope digital cameras typically cost more for less resolution, but they have the advantage of being directly controlled by a computer. They typically provide a better preview image, often with focusing aids, and the ability to acquire the image directly into various imaging software though a TWAIN or plug-in interface. At this time, most 2MP digital cameras output the full resolution image as the preview, while higher MP cameras provide a lower resolution preview than the final still image will be.
Consumer hand held digital still cameras offer the highest resolution still images for very low cost as compared to dedicated microscope digital cameras. Consumer cameras change very quickly with new models every year. Scientific cameras just are not able to keep up. So, consumer hand-held cameras are recommended for routine micrography, especially as a replacement for instant film. They are also recommended for their versatility, being useable both on and off of the microscope, and for the ease with which they can be moved from one microscope to another. The images are stored on internal memory cards from which they must be downloaded to the computer. This can present a problem if the image files need to be named as they are saved, and also may be inconvenient if the images need to be manipulated or measured immediately upon being captured.
Digital video (DV) cameras with an adapter is the easiest way to acquire digital video from a microscope. With the introduction of high definition video camcorder, high definition video microscopy is affordable. Various microscopes with outstanding results like other DV camcorders that we have used in the past, can be controlled by a computer via fire wire. Recordings can be made to the internal DV tape, or captured directly into a computer. But, we think the primary use of video microscopy will be to enhance classroom displays. The move in recent years from classroom TV monitors to video projectors have greatly increased screen sizes, and meant that standard video microscopy often looks very grainy on a large projection screen. High definition classroom displays affordable for the first time.
The heart of every digital camera is the sensor. All sensors are analog devices, converting photons into electrical signals. The process by which the analog information is changed to digital is called Analog to Digital Conversion. This can occur within the Sensor itself, or within the camera, or within the PC, as was the case with older video camera or frame grabber technology. The Sensor size is another consideration. The larger the Sensor size, actually the larger the individual pixel size, the lighter sensitive the Sensor should be, so larger is better, at least in theory.
The sensor resolution is the total number of picture elements forming the image. Resolution ranges from 0.3 Megapixels or MP for 640×480 standard video resolutions to over 10MP. There is a 4x jump in total pixels from 0.3MP to 1.3MP, roughly double the resolution both horizontally and vertically, 0.3 x4 = 1.2, so we can observe a vast improvement in 1.3MP cameras over older video resolution cameras. Images in this category are still relatively small in file size, so are fine for email in jpg format. Next come 2MP and 3.3MP cameras which are less apparent improvements over 1.3MP. If we reach 5MP that represents 4 x the total pixels of a 1.3MP camera, 1.3 x4 = 5.2, so 5MP is the next big leap. Eight, ten, twelve MP cameras, again, are improvements over 5MP cameras, but the next big 4x step will require 20MP cameras which will in all probability exceed the resolution of the microscope optics. Indeed, we have experienced empty magnification even in 8MP cameras. In general, higher megapixel images can give greater detail over a wider field-of-view, allow for cropping more detailed areas of interest, and can yield more accurate measurements. They can also be used to make larger photo quality prints.
