The MicronEye comes standard with a C-mount lens. Special applications may require the use of other lenses or filters which are not of the C-mount variety. C-mount adaptors are available for the more common lens types discussed below.

Three common lens types are the C-mount series, U-mount series, and L-mount series.

The C-mount Lens - The C-mount has a flange focal distance of 17.526mm (.690"). The flange focal distance is the distance from the lens mounting flange to the convergence point of all parallel rays entering the lens when the lens is focused at infinity. The C-mount lens is the work horse of the TV camera world.Its format is designed for performance over the diagonal of a standard television camera videcon. This lens was selected by Micron because of its popularity and ease of availability. The mounting thread characterics are: 1" diameter, 32 threads/inch (machinist thread information 1"-32um2A). Generally, this lens is an excellent choice for the OpticPAM. However, due to geometric distortion and field angle characteristics, short focal length lenses should be evaluated as to suitability for metrology (measurement) imaging. For instance, an 8.5mm focal length lens should not be used with an image sensor greater than 1/8" in length (the OpticRAM is .174") if the application involves metrology. Also, the majority of lenses should not be used wide open because of the light falloff characteristics. The lens-to-OpticRAM distance has been established by using the flange focal distance dimension for fixed focal length lenses (non-adjustable focus). For close-ups, lens extenders will be required. The lens extender is used behind the lens to increase the lens to OpticRAM distance. Spacer Lens (in mm) = Focal Length / Magnification For a given lens, as magnification increases the distance between lens and focal plane decreases. Figure F-2 contains graphs of object distance versus magnification for common C-, U-, and L- mount lenses. These charts are a- useful "ballpark" guide for lens focal length selection.

The U-mount Lens - The U-mount lens is a focusable lens having a flange focal distance of 46.52mm (1.7913"). The characteristic of the mounting threads is M42x1. This lens was primarily designed for 35mm photography applications. A C-mount to U-mount adapter can be purchased from most camera stores.

The L-mount Lens - The L-mount lens is a fixed-focus flat- field lens designed for committed industrial applications. This lens was originally designed for photographic enlargers. The flange focal distance is a function of the specification of each lens selected.

Microscope Lenses - There are standard microscope lenses available. These are to be used in applications where a magnification of less than one is required. However, a microscope lens to C-mount adapter in most cases needs to be individually designed because generally long lens extenders are needed.