help! can't focus on 40x

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starguy75
Posts: 41
Joined: Sat Sep 03, 2016 9:38 pm

help! can't focus on 40x

#1 Post by starguy75 » Mon Oct 10, 2016 3:51 pm

I can look at water samples fine with 4x,10x objectives with the 10x eyepiece but as soon as I try to use 40x objective i can't focus at all, is this normal or did I break it?

starguy75
Posts: 41
Joined: Sat Sep 03, 2016 9:38 pm

Re: help! can't focus on 40x

#2 Post by starguy75 » Mon Oct 10, 2016 4:42 pm

I figured it out, I wasn't getting close enough to the slide with the 40x, I was afraid I would crash into it, it works.

carlh6902
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Re: help! can't focus on 40x

#3 Post by carlh6902 » Mon Oct 10, 2016 5:03 pm

Starguy,

Assuming you have a scope with parfocal optics (all modern scopes are), the best way to do this is to start at lowest power and achieve a focus. Then as you go up to the next higher power, you should already be at (or very near to) the proper focus point. So if you focus and center the specimen at low power (4x), then move up to the next higher power (10x), you should only need to tweak the fine focus a bit and re-center the specimen. Same thing when you go from 10x to 40x. This method guarantees you don't crash your objective into the slide (assuming you are using the slide with the cover slip on top, and assuming a standard thickness cover slip). You will always need to use a real cover slip on the higher power (40x and 100x) objectives.

Carl
Last edited by carlh6902 on Fri Oct 14, 2016 3:47 am, edited 1 time in total.
--- If you're in the Kansas City area and you need help with an Olympus BH-2 scope, PM me. I love to work on these things ---

JimT
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Re: help! can't focus on 40x

#4 Post by JimT » Mon Oct 10, 2016 10:40 pm

Starguy75, Check out your local library for basic books on how to use your microscope. Even juvenile books can offer good advice. Also search the internet for books and articles on basic microscope techniques. Check out this sites home page for tips and techniques.

When I started the only thing I knew was which end to look thru but a little due diligence and research pays off. Especially for the basic stuff.

JimT

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