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Microscope for individual cells/bacteria?

  1. Jun 6, 2010 #1
    On a whim, I started looking at microscopes on ebay today. I don't really know anything about them though. I'm an amateur astronomer, so I know all about telescopes, but in microscopes, I wouldn't know what to begin to look for.

    I found this one that's just under $300. It says it will go from 40x - 2000x magnification.

    Is it a rip off? It worried me because there are like a hundred adds for the exact same scope, so it's obviously mass produced. If I got something like that, could I see individual cells or bacteria?

    If it is a rip off, any recommendations on something better?

    Thanks.
     
  2. jcsd
  3. Jun 6, 2010 #2

    Mapes

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    Hi Scott.K, welcome to PF. Live cells are transparent, so it's quite difficult to see them with a simple microscope. You probably want a http://www.google.com/images?q=phase contrast cells" microscope, which includes slightly more complicated optics. Make sure you let the vendor know that you want to observe cells, so they can steer you towards the right scope.
     
    Last edited by a moderator: Apr 25, 2017
  4. Jun 6, 2010 #3
    Hmmm... it all depends on how much you are willing to spend. I mean PCMs as mentioned above would be the best bet for viewing any living cells but they are pricey. You could see them on other sorts of microscopes but they would in most cases be quite faint. You could however view the cells by staining them. :tongue:.
     
  5. Jun 7, 2010 #4

    Andy Resnick

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    I don't see any link to the microscope you are interested in, but here are my thoughts:

    1) you get what you pay for. Cheap microscopes abound on eBay etc, and are not worth the photons used for you to see the ad.
    2) I suspect you are looking at a cheap microscope because the magnification is presented as a useful spec. In reality, the *numerical aperture* is the metric of interest.
    3) For a cheap microscope, I heartily recommend the Digital Blue QX-5. It's a remarkable feat of engineering.
    4) For looking at cells and bacteria, you need specialized optical techniques: typically people stain the cells (HE (hematoxylin and eosin) staining is very common for commercial slides). Absent the stain, you need to perform something like phase contrast imaging with requires specialized objectives and condenser filters.
    5) a good source of inexpensive decent microscopes is medical students- when they are done with whatever class they needed a microscope for, they will usually sell them at a decent price.
    6) An inexpensive *used* decent-quality microscope with phase contrast optics will cost around $1-2k.
    7) An inexpensive *used* decent quality microscope with brightfield-only, a condenser, and a set of lenses will cost about $300-500.
    8) Feel free to contact me off-line for additional information. I have 6 scopes in my lab and have built several others.
     
  6. Jun 7, 2010 #5

    Borek

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    In my (limited) experience 2000 magnification is a fairy tale, especially in the cheap microscopes. I think it is better to buy a decent used one aiming at 600, perhaps 900.
     
  7. Jun 7, 2010 #6
    Last edited by a moderator: Sep 25, 2014
  8. Jun 7, 2010 #7

    Andy Resnick

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    Oh, the Amscopes. I've never used those, but here are my concerns:

    1) The illumination source is adequate, but cannot be aligned.
    2) The sample stage (focus) is fairly coarse- making it difficult to keep the sample in focus, especially for high NA lenses.
    3) The objective lenses are DIN lenses, but most likely inferior quality- they are spec'd as achromats. Fortunately, you can buy used Zeiss DIN lenses cheap, and those should work much better than whatever comes with the scope. That said, decent quality lenses will outperform the focus drive.
    4) The higher magnification present on the eyepiece, the worse the image quality- field curvature becomes terrible at 16X and 20X is even worse.

    Bottom line, you can do better. For example:

    http://cgi.ebay.com/GREAT-Nikon-Bin...tem&pt=LH_DefaultDomain_0&hash=item45f31c9a27

    http://cgi.ebay.com/Carl-Zeiss-Micr...tem&pt=LH_DefaultDomain_0&hash=item2ead71f886

    In the end, it really depends on what you want to do- looking at pond boogers is easy, and does not require much. Looking at bacteria is much harder.
     
  9. Jun 7, 2010 #8

    Andy Resnick

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    Scott.K-

    Hang on a second, I don't want to send you off in a direction you aren't ready for.

    I don't have a feel for your comfort level with microscopes as instruments- can you tell me more about your telescopes?
     
  10. Jun 7, 2010 #9
    I think the Nikon one would be a great buy. We had very similar ones at highschool and they never let me down :smile:.
     
  11. Jun 7, 2010 #10
    I have a Celestron 8" sct as my primary scope. I had a 4.5" meade, but that just sits in the closet now. lol. I've managed to do astrophotography on a couple of different levels, but I haven't had the time to do deep sky like I want to. That's why I'm looking into microscopes. I never have enough time, energy, or clear skies to drive out away from the city and attempt to do deep sky imaging.

    Here's a video I made of the moon...



    I'm sure I could handle focusing a high power microscope, but I'd rather keep in the 200-300 dollar range if the difference to $400 is negligible.
     
    Last edited by a moderator: Sep 25, 2014
  12. Jun 7, 2010 #11
    Holy crap, scott great resolution in that video. :rofl:
     
  13. Jun 7, 2010 #12

    Andy Resnick

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    Ok. Well, I saw the celestron sell for about $1k- you would be surprised if you could find a similar performing scope for $300, right? It's the same thing with microscopes.

    Again, in microscopy, magnification is *not* the correct metric to use, it's NA. NA is what lets you resolve fine detail: magnifying a blurry spot gives you a large blurry spot.

    I'm very serious about the digital blue QX-5 as a starter microscope. Consider that the equivalent of the Meade 4.5". The equivalent microscope to your celestron is something like the Nikon E100, Leica DM750, Zeiss Primo Star, etc.

    Good deals can be had on used scopes as well- the key is knowing what you want to look at. A stereo zoom scope is good for looking at some things, a compound microscope for others.
     
  14. Jun 14, 2010 #13
    I have that exact same microscope that I got off of ebay for about $300 (from the same seller too!). I did not know it was cheapo microscope as it seems to work for me. I have a collection of pre-prepared slides and I can see single cells just fine.

    I believe these are the standard type of microscopes used in high school and college labs so they can't be that bad.
     
    Last edited by a moderator: Sep 25, 2014
  15. Jun 14, 2010 #14
    Cool. I still haven't really decided. I won't be able to get one until September anyway. All the reviews I've read on the Amscopes say that they're pretty nice. The only thing people have mentioned to me is that the eyepieces are not top quality, and that the objectives could be better, but for me, I doubt it would make a difference anyway, seeing as how I've never owned a microscope, and I would have nothing to compare it to.
     
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