Use of telescopic imaging in intravital microscopy: a simple solution for conventional microscopes.

Conventional microscopes can be adapted for telescopic imaging by using a projection eyepiece which focuses the image formed by a standard microscope objective at such a large distance that light emanating from points on the object leaves the eyepiece as parallel bundles. A telescopic transfer lens forms the final image in its focal plane independent of the distance between the eyepiece and the transfer lens. In the system reported in this paper, the distance between the eyepiece and transfer lens can be varied from 0 to 280 mm without appreciable vignetting or image degradation for imaging on 35 mm film or smaller formats. This allows great flexibility in the vertical location of the plane of observation while permitting rigid fixation of the recording system-transfer lens combination. By use of a 45 degrees rotatable mirror between the transfer lens and the recording systems, two or more recording systems can be securely mounted and adjusted in advance and rapid selection among them can be made during the course of an experiment.