I have a Graf-Apsco microscope with a 10X eyepiece and 3.5X, 10X, and 44X objectives. If I buy a 20X eyepiece will I have any problems. Is this a normal thing to do to increase magnification? Would buying a 100X objective be a better way to go? Can I use an oil immersion on a microscope that does not have one now? I want to study mushroom spores and lichens. What I have now works good but is not powerful enough sometimes. I have been using microscopes off and on for many years but never became involved in the technical details
Thanks for any help
David Smith
basic eyepiece question
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Charles Krebs
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David... you can get a "stronger" eyepiece. That will magnify the image formed by the objective, making things appear larger. It will not, however provide any more resolution. The amount of detail that is resolved is determined solely by the objective, and specifically its numerical aperture. Now, even though there will not be any additional detail resolved, the detail that is there will be "enlarged" and therefore it is likely you will be able to observe small structures somewhat better than with a 10X. I might suggest a 15X eyepiece. With a 15X, you should be able to see just about all the detail that your objective is resolving, and it is easier to keep your eye aligned over the eyepiece. (BTW.... when you magnify an objectives image beyond what is needed to discern all the resolved detail you get what is called "empty magnification"... things are bigger, but you are not getting any more information).
You can use an oil immersion objective even though you do not now have one. Ideally, to get the most from an oil immersion objective you will need to have a condenser that has a numerical aperture at least as large as the objective. If the numerical aperture of the objective is over 0.95, the best resolution will occur when the slide is also oiled to the condenser. Frankly most people don't oil the condenser to the slide, but it is the only way you can get the resolution that a high NA 100X can potentially provide. Without oiling the condenser to slide the largest numerical aperture you can obtain is about 0.9 to 0.95. If your 44x has a NA of about 0.65-0.7, then even when used without an oiled condenser, you would be resolving more detail with a typical 100x objective (the objective must still be oiled to the slide).
Working with an oiled 100X is not something everyone enjoys.
It might make sense to see if a stronger eyepiece accomplishes what you need first.
Charlie
You can use an oil immersion objective even though you do not now have one. Ideally, to get the most from an oil immersion objective you will need to have a condenser that has a numerical aperture at least as large as the objective. If the numerical aperture of the objective is over 0.95, the best resolution will occur when the slide is also oiled to the condenser. Frankly most people don't oil the condenser to the slide, but it is the only way you can get the resolution that a high NA 100X can potentially provide. Without oiling the condenser to slide the largest numerical aperture you can obtain is about 0.9 to 0.95. If your 44x has a NA of about 0.65-0.7, then even when used without an oiled condenser, you would be resolving more detail with a typical 100x objective (the objective must still be oiled to the slide).
Working with an oiled 100X is not something everyone enjoys.
It might make sense to see if a stronger eyepiece accomplishes what you need first.
Charlie
