List Price: $1,000.00
Sale Price: $239.98
Today's Bonus: 76% Off
AmScope 40X-2000X Lab Vet LED Monocular Compound Microscope with Double-layer Mechanical Stage
AmScope 40X-2000X LED Monocular Digital Compound Microscope w 3D Stage and 1.3MP Camera
The AmScope M620 is a very nice microscope for the price, with all the usual lab-scope controls in the usual places, nice features and pro feel. It's only $160 ($240 with the 1.3 MP imager), while other brands sell lesser models for considerably more. It has some minor flaws in the optics but is otherwise nearly entry-level lab-grade.
Why this one, and not a cheaper model? Condenser focus, iris diaphragm, filter ring, mechanical stage, and 4 objectives. You do get all those on a cheaper model. Get a USB imager instead of a more expensive binocular 'scope, you'll be glad you did. Viewing on computer screen is so much easier than using an eyepiece, and you can expand your hobby into photomicrography. Don't get a .3, get at least a 1.3 or 3 megapixel imager.
It arrives double-boxed in a molded styrofoam container. Keep it for moving/shipping! Mine arrived with the camera in bubble wrap and floating around loose in the box, and a scratch in the paint on the optical tube. It came with a useless one-page instruction sheet, (and missing the "User's Microscope Manual"), and no tools. You'll need a tiny jeweler's screwdriver for the eyepiece tube, and a couple metric Allens for the condenser and head adjustments. Mine came with everything just a bit out alignment. You need to go online and study microscope optics and align the thing properly, if you really want to fine-tune it. The pivoting head, condenser, and LED light can all be centered with little screws and lots of patience.
AmScope's descriptions are a bit off some of the ad-wordage on this model was obviously taken from another model, probably the B120, which is the binocular version of this microscope. "Lab Vet" not this is an "advanced student" (high school) microscope, optically no where near any professional 'scope. It's a $160 microscope, competing well with other brands at the $350 level, but any real "lab" microscope starts at $1200+.. Indeed, a single lab-grade objective lens costs more than this whole microscope. But it's more than good enough for hobby and educational purposes, and it will teach one how to safely and properly handle an expensive pro model.
"Abbe" condenser not really it's a single, uncorrected lens with focusing rack and iris diaphragm. But it does the job, and it even has a tiny up-stop setscrew you can set so you can't rack it up too far and hit the slide. (Likewise, it also has a focus-stop setscrew and you want to set that so the 100x lens almost touches the coverslip.) If you turn the condenser focus knob quarter-turn down from top, it focuses on infinity; near the bottom of its travel it focuses on the light. To remove the condenser, you first unscrew and remove the lamp cover/lens, then loosen the condenser setscrew, the drop it down out of its holder ring (don't hit the LED). You can then unscrew the top lens, but there's no other lens in there to use for the low-power objectives, like a real Abbe would have. To center the condenser, it has 2 Allen setscrews in front, and a spring-loaded pin in the back; these hold and center the dovetail ring that holds the condenser.
"Professional 30 degree inclined 360 degree swiveling monocular head" not it's 45 degrees, I measured it with a Dasco angle finder.
Illumination: The lamp is a more than adequate LED light with frosted hemispherical lens and variable brightness. But no field aperture iris. Can do "critical" illumination, but strictly speaking, not "Kohler." Still, it has enough adjustment to make your lighting work OK for all 4 objectives. You just have to experiment and find the "happy" setting of condenser focus and iris opening for the selected objective and specimen. Go online and study the trade-off between contrast and resolution to learn how to set condensers properly. The iris lever has no NA markings; but the condenser says "N.A. 1.25" on the top, matching the 100x OI objective. One might suppose that means wide-open, but who knows? In almost all cases, the best resolution occurs with the condenser near the top and the iris nearly closed.
Filter: The condenser has a swing-out filter holder, 32 x 2 mm (you should cut your homemade filters 31.75mm). Black one out with something and swing it out a little to create a crescent oblique lighting, which is quite nice and useful for many specimen, gives a sorta 3D effect. Also, it's easy to make darkfield patch stops, and Rheinbergs, with your x-acto circle cutter, overhead transparency plastic, clear packing tape, electrical tape, and Roscoe Strobist filter kit, etc. Making all sorts of filters and stops is lots of fun.
Stage: The cast aluminum frame and stage are fairly rigid. The x-y stage and fine focus controls are nice and thick-greasy with almost no grease-tension backlash. The gearing is way too touchy at 100x obj but you get used to it. The stage has just enough flex to notice in your focal field when touching or moving stage at high power. It is a very solid machine, but it does flex just a tiny bit.
The stage has one BIG design flaw: it only travels fore and aft 20mm, so to scan the lower 5mm of a slide, you have to turn the slide around. The specs, and the scale on the side, say it moves 30mm, but it is internally stopped at 20mm, and it must be, because if it traveled further back it would hit the frame, and if further forward, the condenser. There is no way to correct this; the entire frame would have to be 5mm deeper.
Optics: The 4 objectives (4,10,40,100) are achromats, correcting only one color (as opposed to apochromats that correct 3 colors), and not planatic (ie, focus not flat). Meaning that what you will see is some color fringes, and not a perfectly flat focus field. That's normal and expected at this price-range. The 40 and 100 are spring-loaded, and have parfocal adjustment rings (under the cover tube), and they are extremely touchy. But after a couple hours, you can get the parfocal almost perfect. The rotating prism head has three setscrews and you can play with them for several hours and get pretty good parcentering. Look online for tutorials on how to do these alignments, if needed. The prism in mine came a bit dirty, and is impossible to properly clean without major disassembly (best done by a repair shop).
The M620B comes with 10x and 20x eyepieces; the 10x has a big needle pointer (with a bent tip); using the 20x with the 100x oil objective provides 2000x magnification, which is called "empty magnification" -anything over about 1250x is just numerical marketing baloney, exceeding the capabilities of any light optics. The best high-res air picture is with the 40x obj and the 20x eye for 800x; or you can dip the 100x OI in oil but bacteria are still just itty-bitty dots and rods. Note that the 100x is made to be used only in immersion oil, and it will look poor in air. The 'scope comes with a tiny bottle (about 6 ml) of immersion oil; after that, order some Cargill type A from TedPella. There are several good videos on youtube about how to use oil-immersion lenses.
Upgrading: Yes, everything is a "standard" size: The design length is 160, eyepiece tube is 23, the condenser holder is 37, the filter holder is 32, and the objectives are DIN standard. That means you can change out the optics with expensive pro lenses, if you have the money and the need to do so. A 60x plan-apo would be a nice addition...
Imager: I got mine with the 1.3 megapixel USB imager, which provides 1280x1024, the same as my second LCD monitor. Viewing your specimen on a computer monitor is much better than centering your eyeball exactly some mm over an eyepiece for 99 hours... Go ahead and get an imager it makes the microscope much easier to use, and you can snap pictures and make videos and share your discoveries.
The FMA037 0.5x camera adapter I received has tiny bubbles in the optical coatings, and several internal rainbow reflections, both visible at high contrast setting (iris closed). I disassembled it and carefully cleaned its lenses and it didn't change a thing. If you hold the camera still and rotate the adapter (it threads into the camera), you see them rotate. This is very annoying, even at this price. Lens coatings shouldn't have bubbles.
Software: The AmScope ToupView software is quite nice! It has lots of camera image controls, and lots of drawing controls for annotation and measurement. It even has a focus stacker (like Picolay) it calls "Manual Fusion" that works well. You can watch full-screen, or snap photos or video. Unfortunately, it only does AVI and MJPEG-WMV video, whilst x264-MP4 is state-of-the-art nowadays. The video frame rate peaks out at ~13.5 FPS but will be much slower if the light is too low. It does have measurement features but you need a micrometer slide to calibrate it. I determined experimentally that the 4x is seeing ~3.5mm (3500um) HFOV at 1280 pix, and put in derived factors for the 10, 40, and 100. It's close enough for hobby purposes. ToupView has one little bug: you press Esc key to go full-screen, but pressing again doesn't restore to normal window! Workaround: hit Win-Tab to reselect the ToupView window, then hit Esc and it'll work.
OK, so should you buy one? Would I buy again? Yes, it's situated between student and pro, leaning a bit toward the latter. At this price, you can live with some minor optical aberrations and the 20mm stage limit, and it's otherwise configured like an expensive lab microscope. Most of all, it won't break the bank.
I will expand this microscopy hobby on my web site as I learn more about it it's a fascinating multi-hobby loaded with endless fun.
--kv5r dot com
Click Here For Most Helpful Customer Reviews >>
We are a homeschooling family; I bought this microscope not only for our homeschool use, but also to use for a biology class I am teaching to 2-3 graders at a local coop. It is easy to use. It does take some getting used to when you attach the camera and connect it to the Mac. The focusing is a little harder than when you are looking through the lens yourself; it is a little harder to get the lighting right when it is connected to the computer, too. However, all of that is worth it if you are showing a bunch of kids (there are 18 in my class) something. I put some water on hay for a couple of days and in class we took a drop of it and saw the protozoa racing across the screen. It was very neat. The kids are so curious with the microscope that I invited them to bring things next week for us to look at up close and personal!The "manual"---I use that term very loosely--is terrible! There were no instructions on how to connect the camera to the microscope (and, no, it is not obvious). I called the amscope company and their customer service rep was excellent at explaining what to do. I told him they needed to put an actual manual with the microscope and he agreed; I believe he said they are working on it.
No comments:
Post a Comment