Fig. 1. Components of continuous zoom operating microscope^[11]

Fig. 2. Diagram of mechanical compensation. (a) Positive group compensation zoom; (b) negative group compensation zoom

Fig. 3. Diagram of vignetting of optical system

Fig. 4. Diagram of tangential vignetting

Fig. 5. Variation of vignetting coefficient with angular magnification

Fig. 6. Variation of vignetting coefficient with focal length of compensation group

Fig. 7. Optical path diagrams and illuminance curves under different focal length distribution

Fig. 8. Structure diagram of optical system

Fig. 9. Diagram of glass parameter

Fig. 10. Fitting cam curves

Fig. 11. MTF curves. (a) 0.4×; (b) 1.3×; (c) 4.0×

Fig. 12. Distortion curves. (a) 0.4×; (b) 1.3×; (c) 4.0×

Fig. 13. Tolerance analysis curves. (a) 0.4×; (b) 1.3×; (c) 4.0×