1. Review in your lab manual the parts of a microscope. Ocular lens Objective lens Specimen Condenser lens Light source 1

2. Compound Binocular Light Microscope Compound microscopes have more than one lens. Ocular Lens Objective Lens 2 3. Your microscope is also binocular. Two Oculars 3 4. Identical images pass to both oculars. 4 5. Prism Binocular microscopes split light into two paths. Light Path 5 6. Interpupilary Distance Your microscope is binocular. 6 7. Your microscope is binocular. Adjust the Interpupilary Distance 7 8. Adjustable Ocular Adjustment Ring Microscope oculars are adjustable. 8 9. Microscope oculars are adjustable. Begin with a slide in place. 9 10. Open Eye Closed Eye Focus Using Fine Adjustment Knob Focus while viewing through the non- adjustable ocular. 10 11. Open Eye Closed Eye Focus Using Ring of Adjustable Ocular View only through the adjustable ocular. 11 12. Light microscopes use visible light to form an image. 12 13. Electron microscopes use radiation of small wavelengths to make sharper and higher resolution images. Electron Microscope 13 14. Magnification allows us to see beyond our limited senses. 14 15. 1X magnification 10X magnification Magnification 15 16. 10X magnification objective 4X magnification objective 40X magnification objective Objectives 16 17. Oculars are typically 10x magnifiers. 17 18. 10X X 4X = 40X Ocular Magnification Objective Magnification Total Magnification X = Oculars and Objectives combine to provide Total Magnification. 18 19. 1X Total Mag. 40X Total Mag. 4x Objective with Ocular provides 40x Total Magnification 4X Objective 19 20. 1X Total Mag. 40X Objective 40x Objective with Ocular provides 400x Total Magnification 400X Total Mag. 20 21. Resolution is the ability to distinguish between two points that are close together. Good resolution depends on both magnification and lens quality. RESOLUTION Low Magnification High Magnification Higher Resolution of individual legs 21 22. Lens Quality Improves Resolution 40X Magnification Poor Quality Lens 40X Magnification High Quality Lens Better Resolution 22 23. Field of View (FOV) FOV is the area of the specimen seen through the microscope. Field of View 23 24. Field of View Low Magnification Large FOV High Magnification Small FOV 24 25. Field of View Measure field of view with low magnification. Field of View is about 2.5 mm diameter at 40X total magnification. 25 26. FOV low mag. X Mag. low = FOV high mag. X Mag. high Calculate Field of View at High Magnification For example, if the FOV diameter is 2.5 mm at 4X then at 100X the FOV diameter is 0.1 mm. 2.5 mm X 4X = FOV high mag. X 100X 0.1 mm = FOV high mag. 26 27. Depth of Field (DOF) DOF refers to the thickness of the specimen that is all in focus. The higher the magnification the thinner the DOF. Chloroplast within the DOF is in focus Chloroplast below the DOF is out of focus 27 28. Working Distance Working distance is the distance between the tip of the objective and the specimen. Working Distance [] 28 29. Stereoscope 29 30. Normal vision has depth perception. We see the world in 3 dimensions. Height Width Depth Width Height 2 Dimensions 3 Dimensions 30 31. Light Path Light Path Stereoscope combine magnification with 3 Dimensional images. Two aligned light paths Objective 31 32. Dissection or surgery requires 3D vision. 32 33. Compound Light Microscope Stereoscope Image Dimensions 2 Dimensions 3 Dimensions Magnification High Low Compound Microscope VS Stereoscope 33 34. Working Distance Stereoscope provide a greater working distance. 34 35. Compound Light Microscope Stereoscope Working Distance Low High Magnification High Low Image Dimensions 2 - Dimension 3 - Dimension Zoom Magnification No Yes Compound Microscope vs Stereoscope 35 36. Ocular Stage Zoom Magnification Focus Knob Objective Specimen Parts of a stereoscope 36 37. 37 Photo Credits Slides 1-3: Darrell Vodopich; 4 (top): Darrell Vodopich; The McGraw-Hill Companies, Inc./Don Rubbelke, photographer; 5-12: Darrell Vodopich; 13: Centers for Disease Control/James Gathany; 14-17: Darrell Vodopich; 18: Steven P. Lynch RF; 18-36: Darrell Vodopich Line Art Credits Slide 2: Sylvia Mader, Biology 7e 2001 reproduced with permission of McGraw-Hill Education