Name: April
Status: other
Grade: other
Location: IL
Country: N/A
Date: September 2006
Question:
What advantages does the low-power objective lense
have over the oil immersion objective for viewing fungi?
Replies:
April,
As long as you can see enough detail with the low power lens, you will get
much greater depth in your field of view. Field depth relates to how much
of the object you can have in focus at once--reguarding foreground,
middleground and background. A low power lens generally can focus all
three, where the higher powered lenses can only focus in on one. The oil
immersion lens is primarily used only to view extremely small things and
since the lens is almost touching the plate, oil must be used to protect the
lens. It also affects the refractive index of the light. I don't think
that this has anything to do with the change in the field depth, but it's
important information so that you don't wreck the lens. Also a low power
lens generally doesn't require as much light, so if your object is light
sensitive or heat sensitive (ie it is still alive), then a low power lens
will be nice because you don't as high of wattage.
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