I'm going to need to buy a microscope

[ChrissySC]

?

 

Brand, book, page, price? Make it simple? 3rd grade science worthy.

 

 

http://www.freyscientific.com/Resources/HowtoChooseaMicroscope/tabid/91/Default.aspx

 

Explains well - with term definition.

[Iucounu]

Any thoughts on this Celestron 44104?

 

Celestron 44104 500x Power Advanced Biological Microscope $119

 

... together with this camera?

 

Celestron Digital Microscope Imager $42

[amsunshine]

Hmmmm, when my 4 yr old asked if we could buy a microscope to he could "see little things bigger," I figured I might as well buy a decent microscope even though he is only 4. So I bought this one: http://www.amazon.com/gp/product/B000NOU54O/ref=oh_o03_s00_i03_details

 

Now I'm starting to wonder if I just wasted $60! LOL, I was thinking that was pretty expensive as far as microscopes go...apparently not!

 

It hasn't arrived yet...but I'm hoping it will serve our purpose for the next couple of years until they're old enough for one of those fancy microscopes...lol.

 

No, you didn't waste money. It's a very nice little scope for young ones -- and it's nice that it is battery operated. We have one and although we will get a much nicer one for junior high/hs, this one is perfect for the years prior, imo.

Edited March 19, 2012 by amsunshine

[H0MEFree]

Keep an eye out on Ebay. Stay away from anything that could be bought at a museum or ToyRUs.

 

I got a "National" for only $60 on Ebay. One of the best purchases I ever made and for a killer deal.

 

 

 

 

 

 

 

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[Education Explorers]

Don't confuse "stereo" and "binocular".

 

A stereo microscope (also called a dissecting microscope) uses two objective lens and two eyepieces to provide a three-dimensional view of the object. Stereo microscopes operate at low to medium magnifications, typically in the range of 10X to 40X. Some models have zoom, so you can vary the magnification over a range.

 

A standard (compound) microscope uses only one objective lens to provide a two-dimensional view, but the image from that lens may be viewed with one (monocular) or two (binocular) eyepiece lenses. (Actually, there are trinocular models that have a binocular setup for one user and a third, single eyepiece for a teacher or to mount a camera.) Compound microscopes usually offer three, four, or five discrete magnifications, with 40X being the lowest and 400X or 1000X being the highest.

 

Many people prefer a binocular compound microscope to a monocular, but the former does have some disadvantages. First, in models of similar optical and mechanical quality, the binocular model will cost significantly more. Second, if two or more people are using the microscope, the binocular model can be a pain in the butt. Each time the other person wants to use the scope, you may need to adjust both the diopter setting on the second eyepiece and the distance between the eyepieces. Third, unless the scope is perfectly adjusted, which they often are not in inexpensive models, the images from the two eyepieces may be just slightly out of sync. That may be so subtle you don't notice it, but it can lead to eyestrain.

 

There is a quick, easy solution for you, if you don't mind looking like a pirate. Just buy an eyepatch with an elastic band. I picked one up at a toystore for a buck or so and have been using it for years for astronomical observing.

 

First of all, I want to say how much I appreciate your time in elaborating on the different microscopes. We need to purchase one now for next year. We will be teaching Middle School and Elementary Biology. I have no desire to purchase another microscope for high school. If we have kids who want to take AP Bio, I guess we will have to address the issue at that point. I just want to make a solid purchase that will be effective throughout our studies. Like anyone else, I would like a good value for my money. Your responses have been extremely helpful and timely for our family.

 

I have forwarded this thread to my husband and he had a specific question that perhaps you could address. He emailed me,

 

"I have always had trouble seeing through a single viewer like a microscope. There are ways to transmit the view to a screen, which to me makes it much more pleasurable to use. Some of them are build into the microscope, some are cameras that clamp on. I would like to check them out."

 

Do you have any specific information about cameras which would allow the transmission to a screen? If so, what are the cost involved?

 

Thanks!

Edited March 19, 2012 by Education Explorers

[TheHomeScientist]

Do you have any specific information about cameras which would allow the transmission to a screen? If so, what are the cost involved?

 

Thanks!

 

Well, for a microscope sufficient for high school through AP biology, you'll want something with a 100X oil-immersion objective (for 1,000X magnification) and a mechanical stage. That puts you in the $225+ range for a house-branded scope, or about $350 and up for a better quality brand like National Optical. That's assuming a monocular head. For a binocular head, you'd typically add $50 to $150.

 

As far as displaying the image on a screen, almost any microscope camera can display the image in real-time on a computer display. The problem is that cameras with reasonable quality aren't cheap. You can buy a cheap one for $60 or so that has very low resolution (640x480), but anything that provides a decent high-resolution image is going to cost $200 or more, possibly much more.

 

I just looked at the HST digital microscopes page, and the least expensive model that would be suitable for AP biology is something like $650, a significant percentage of which is the cost of the camera.

 

The other thing is, except with very high-end equipment, an image on screen isn't going to be anywhere near as good as what you can see actually looking through the eyepiece.

 

Your husband's problem may be with eye relief, which is the distance between the outer lens of the eyepiece and the eye. People who wear glasses often have problems using standard eyepieces, as do some who don't wear glasses. You can purchase a replacement long eye-relief eyepiece if the scope you buy doesn't have sufficient eye relief.

[Iucounu]

As far as displaying the image on a screen, almost any microscope camera can display the image in real-time on a computer display. The problem is that cameras with reasonable quality aren't cheap. You can buy a cheap one for $60 or so that has very low resolution (640x480), but anything that provides a decent high-resolution image is going to cost $200 or more, possibly much more.

Any thoughts on this Celestron 44104? It only has 500X resolution, but it would be for a six year old and hopefully last us for a number of years until we need something better. But how about that 2 megapixel Celestron camera for $42?

 

Celestron 44104 500x Power Advanced Biological Microscope $119

 

... together with this camera?

 

Celestron Digital Microscope Imager $42

[Iucounu]

Another question: how is the quality when using a 20X (WF20) eyepiece? It seems that with a lot of 400X microscopes, this would get to 800x magnification, but how bad would the image quality be compared to a 1000x immersion oil objective? Would there be any gain in actual resolution over 400X with a 10X eyepiece (or 500X with a 12.5X eyepiece)?

[TheHomeScientist]

Any thoughts on this Celestron 44104? It only has 500X resolution, but it would be for a six year old and hopefully last us for a number of years until we need something better. But how about that 2 megapixel Celestron camera for $42?

 

Celestron 44104 500x Power Advanced Biological Microscope $119

 

... together with this camera?

 

Celestron Digital Microscope Imager $42

 

I haven't seen those specific items, but I'd expect them both to be decent low-end products, suitable for elementary students through middle-school. Celestron is a decent brand name. The microscope appears to have separate coarse- and fine-focus knobs, which is a good thing, and there even appears to be a mechanical stage, which is another good thing. A 2MP camera has enough resolution to provide a full-screen display, or nearly so, on typical computer monitors. If it were me, I'd check the reviews and, assuming they're decent, go for it.

[TheHomeScientist]

Another question: how is the quality when using a 20X (WF20) eyepiece? It seems that with a lot of 400X microscopes, this would get to 800x magnification, but how bad would the image quality be compared to a 1000x immersion oil objective? Would there be any gain in actual resolution over 400X with a 10X eyepiece (or 500X with a 12.5X eyepiece)?

 

You'll probably run into optical issues. The image will be larger but dimmer, and not much if any additional detail will be visible. That's called "empty magnification".

 

In microscopy, there's a concept called numerical aperture (NA), which applies to both objective lenses and the sub-stage condenser. The rule of thumb is that maximum useful magnification is roughly 800 to 1000 times the numerical aperture of the optical system. A typical "400X" microscope has a 40X objective and condenser both of which are 0.65 NA. That means the maximum useful magnification is about 520X to 650X. (All of that also assumes the optics are "perfect", which of course they aren't in inexpensive scopes.) A "1000X" scope typically has a 100X (oil-immersion) objective with a 1.25 NA and a condenser that's also 1.25 NA, allowing maximum useful magnification of 1000X to 1250X (with a 10X or 12.5X eyepiece). Using a 20X eyepiece on the 0.65 NA scope does provide 800X magnification, but that translates to a larger but dimmer image that has little or no more detail than the image at 400X or 500X.

[Iucounu]

Thank you, Robert. Once more you have been immensely helpful. With regard to empty magnification, there is a similar result in photography when stacking teleconverters on lenses-- past a certain point, there's no point. :)

 

I was wondering what you think of this model:

AmScope 40X-1600X LED Binocular Compound Microscope $239

 

I have read that the AmScope microscopes are decently built for the price, and that though they send little documentation with the scopes, their customer service isn't bad.

 

If I buy this one it will really stretch our budget, so I'd hold off on the camera purchase for now. That might not be a bad idea, as the prices seem to be falling on those year-to-year, with the general advance of manufacturing in digital photography in general.

 

The reason I found this particular model was that I went searching for these features:

* LED illumination

* binocular head (to make it easier for our son to use, especially with the plan to attach an eyepiece camera at some point-- this would allow eyeball focusing with the camera attached)

* mechanical stage

* 100X oil immersion objective

 

Given that 20X eyepieces on 1000X oil immersion objectives seem to really be pushing the envelope on resolution from the samples I've seen, and what you wrote on the limits of useful magnification with a 400X objective, I actually like the idea of a 16X eyepiece a little more than a 20X one. I also found a separately sold 12.5X Bausch and Lomb pair of eyepieces for $30, but I don't want to spend that much extra money right now. The 16X eyepieces coming with this one seem like a plus. Even if they're at the limit of your rough estimate based on "perfect" optics, a 12.5X-16X eyepiece on a 400X objective will probably give some benefit.

 

ETA: I just went back and read your previous comment in this thread:

With inexpensive Chinese scopes, a binocular head typically amounts to a $75 to $150 option. In my opinion, if you're going to spend $75 to $150 more on a scope, you'd be better off going with a monocular head and getting better quality and/or features for your money.

 

I guess this AmScope qualifies as an inexpensive Chinese scope. I will keep searching and sifting through results. I have a ton of microscopes bookmarked now, and I'm starting to discard some of them as my understanding expands.

Edited March 20, 2012 by Iucounu

[Iucounu]

Maybe I should just ask this question: What do you consider to be the cheapest decent-quality LED-illuminated microscope with binocular eyepieces and a 100X objective? Are all of them simply out of my sub-$300 price range?

[TheHomeScientist]

Yes, I've been asked before about this AmScope model. Again, I've never actually seen it, but I've seen enough similar models (AmScope is a store brand of generic Chinese microscope) that I'd expect it to be of decent mechanical and optical quality, with considerable variation due to the lack of strict quality control on scopes in this price range. I'd definitely check the scope as soon as it arrives to make sure it's parfocal and parcentered (as described in our home biology lab book, which there's a download link for somewhere around here...) Other than that, you should be good to go.

 

You have to understand that I'm a lot more critical of microscope quality than most homeschool users would be. Most of them have very little experience in evaluating microscopes, and no basis for comparison. I, on the other hand, am cursed because I know just how good first-tier models from Leitz, Zeiss, Fujinon, and so on really are. On the other hand, those scopes cost anything from $2,000 or $3,000 to $25,000 or more, so it's not really a fair comparison. On the gripping hand, I'm always stunned by just how good National Optical models that sell for $500 to $1,200 are in comparison to premium German and Japanese models that cost literally ten times as much.

 

So, the short answer is that I think (barring you getting a really bad example) you would be very happy with this scope. The specs are fine; everything is there that you want to be there. And this is much more scope than the Celestron model, which'd only take you through middle school. This AmScope model will take you through high school AP Bio work and on to university. So, yeah, my advice given your budget would be to buy this one. You're not going to find a binocular model that's noticeably superior without spending a lot more.

[TheHomeScientist]

Oh, yeah. I'm sure you'll want to try the 16X eyepieces, but I think you'll find they don't add much, if anything. They're more a marketing gimmick than anything else. If I were you, I'd put the 10X eyepieces in place and just use them. It won't be worth your trouble to change back and forth between 10X and 16X eyepieces.