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Microscopes typically have an eyepiece diameter of about 23mm, so a digital camera having a lens barrel of roughly the same diameter may provide a simple means of getting started in the micrography field. Countless suitable models are available at a wide range of prices from the leading camera manufacturers. Check whether the camera has a manual mode and, if so, what is the largest aperture that can be set manually. It is always important to get as much light as possible to the sensor so that the shutter speed can be kept reasonably high to eliminate camera movement. A wide aperture may also help to minimize vignetting effects.

DSLRs are very flexible cameras and can be used to obtain high quality micrography images. However, many models are designed around their film-based predecessors and of course incorporate moving parts. The most significant moving part is the instant-return mirror which flips up to expose the sensor when the shutter release is pressed. This causes a certain amount of vibration from which the microscope must be isolated. This will not be the case if the camera and microscope are attached by  a rigid adaptor. Small movements may be amplified hundreds of times and consequently may lead to unsharp images. The motion of the mechanical focal-plane shutter blades may also cause a certain amount of camera movement. Some DSLRs incorporate a mirror lock option which can be used to reduce vibration but working in this way is of course somewhat less convenient.

The obvious solution to the problem of camera movement is to isolate the camera from the microscope. Both instruments must be held absolutely stable, but an air gap between camera and microscope removes the problem of camera movement. To make this possible, the DSLR must be fitted with a suitable lens which looks into the eyepiece of the microscope. A microscope eyepiece provides an image which is effectively at infinity, so the DSLR lens must be focused accordingly. Another possible solution is to use long exposure periods. The vibrations produced by a DSLR at the beginning and end of an exposure period are relatively short - perhaps 25 - 50 milliseconds - so movement that takes place during only a very small percentage of the total exposure period becomes insignificant. For example, using an exposure period of 5 seconds would render 50 milliseconds of slight camera movement insignificant.

Dedicated microscope cameras typically work in conjunction with a computer, which makes them more expensive and less portable. However, they usually offer convenient ways of optimising and enhancing images prior to an exposure being made, including better preview and focusing aids, and the ability to capture images directly on to a computer using a suitable plug-in or interface. This obviously saves post-capture work and inconvenience.

Dedicated microscope cameras normally include some form of software for controlling the camera. A preview image is made available on the computer monitor although this may be of reduced resolution. High-resolution cameras featuring lower resolution previews may also provide a small user-defined area of the image at full resolution for use as a focusing aids.


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