Magnification: This is the product obtained when you multiply the (objective magnification) X (eyepiece magnification). Since a magnification of 10X in the eyepiece has come to be standard, the range of magnification depends mainly on your choice of objectives.
Resolution: Magnification determines the apparent size of the image. The quality of the image, or the rendering of detail within the image, is a separate function called resolution. Resolution depends primarily on the quality of the objective and the way in which it is illuminated. To exploit the full resolution of any objective, it must be appropriately illuminated by a converging beam or “cone” of light: the higher the potential resolution of the objective, the wider must be the cone. The maximum width of the cone of light that any lens will admit is indicated by its numerical aperture, abbreviated N.A.
Mathematically, N.A. =(Sin. ½ angle of cone) X (refractive index of the medium between the specimen and objective lens)
The N.A. of an objective is usually marked on the objective lens mount (10 / 0.25, 40 / 0.65). The larger the N.A., the higher the potential resolution of the objective.
You may have noticed that the medium between the specimen and objective is an integral mathematical part of the N.A. formula. The N.A. of oil immersion lenses take into account the use of immersion oil as a medium. If immersion oil is not used the potential resolution of the oil immersion objective can never be achieved.
The N.A. formula also includes the shape of the cone of light entering the microscope objective. Without a condensing system built into the stage or below the stage ( substage ) to shape the cone of light to the desired angle, the resolution potential of objectives magnifying more than 40X will be greatly hindered. For a 40X/ N.A. 0.65 objective an N.A. 0.65 condenser should be provided. Similarly, a 100X/ N.A. 1.25 oil immersion objective requires an N.A. 1.25 condenser. For the 100X/ N.A. 1.25 objectives, the situation is even more complex than described above. Not only must an adequate condensing system be used but the cone of light must be properly focused.
Keep in mind that there is a limit to meaningful magnification. When you magnify an object beyond 1000x, it will continue to get larger, but the resolution will stay the same. This will actually make the image blurry and unclear, and it is called empty magnification.
This is why it is not professionally recommended to change the WF 10x eyepiece to a higher magnification eyepiece such as the (WF 15x, 20x, or 25x), because 1000x magnification is the maximum limit of clear magnification achieved with an optical system
How to Achieve the Highest Quality Imaging:
Note: It is important to note that because of our built-in stop the 4X and 10X objectives can never come into contact with your microslides. The 40XR and 100XR may occasionally touch the microslide but because these lenses are in retractable mounts your slide will not be damaged.
(All models equipped with an Abbe-condesner with or without the 100XR oil immersion objective)
1 – 6. Same as in steps A1 through A6 above
Lower the stage and swing out the objective to give yourself room to work. Place one or two drops of quality immersion oil over the slide cover slip, which is needed to gather enough light for viewing with 100xR. Swing the 100xR objective back in place again, and proceed by moving the stage upwards until the lens makes contact with the oil. Continue (slowly) to focus down with coarse adjustment until the color or a blurred outline of the specimen appears. Now complete the focusing with the fine adjustment so that your image details come into sharper focus.
When you are finished using the slides, ensure to clean the oil off of the slides and microscope lens by using lens paper and cleaning solution.
In using the 100xR DIN objective, the most favorable resolution is obtained with the Abbe condenser nearly touching the slide specimen. Ideally, a drop of immersion oil is placed between the condenser and the slide, as well as between the slide and the 100xR DIN objective. Although this practice is not always followed in routine study, it is the only way to take full advantage of the inherent resolution of the 1.25 NA Abbe condenser.
If the body of your microscope falls toward the stage by the weight of gravity and will not stay in a focused position, it is said to be “drifting”. It is the result of loss of tension in the pinion mechanism due to normal and constant use. The tension is easily and quickly adjusted. You need not employ the services of a microscope technician to perform the function.
To correct for drift you will need the small metric allen wrench that is supplied with every microscope. Immediately to the right of the left coarse focus knob there is a pinion tension adjustment ring. Using the allen wrench, loosen the allen screw of the adjustment ring. This will allow you to turn the adjustment ring in a clockwise motion in relation to the coarse focus knob. A ¼ to ½ turn is all that should be necessary. Again tighten the allen screw.
Test the tension. If the microscope body still drifts, repeat the procedure above. If the tension is now too tight, reverse the procedure. A little practice will make you an expert in adjusting the drift control.