Amscope T490 Questions

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natedoggraymond
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Amscope T490 Questions

#1 Post by natedoggraymond » Tue Feb 09, 2021 8:40 am

Hey all! This is my first post on the forum, so excuse me if I have done something bothersome by starting a new topic or posting in the wrong section. Any advice would be welcome!

I have been shopping for my first microscope for some time now and have narrowed it down to a few scopes. My goals with microscopy are discovery, personal research, and microphotography/videography. I seek to look at, identify, and learn more about microbes of all kinds. I intend to begin with the somewhat larger pondwater protists. I am a young college student and a passionate biology major. I could see my career or some of my research coming out of my experience with microscopy. It is certainly something I love. I have been greatly inspired by the work of James Weiss and Hank Green with Journey to the Microcosmos and dream of creating and/or experiencing content like theirs.

Basically, I'm looking for a microscope that is EXPANDABLE. I think darkfield, phase contrast, polarized light microscopy, Kohler illumination, microphotography, and all of the fun bells and whistles of this hobby are very appealing. Thus, I would like my first microscope to be one that, while not breaking the bank, can take me decently far with later upgrades and add-ons.

I have researched several options and have discovered that Amscope and Omax are the same company and both offer decent expandability. Within those companies, the Amscope T490B-LED microscope https://www.amscope.com/40x-2000x-led-t ... scope.html seems to fit the bill almost perfectly and I have deemed it my top choice. However, I have some big lingering questions that I have had difficulty finding answers to. I have reached out to these companies and have received mixed answers. If any of you can help me answer them definitively and thoroughly so that I can make an informed purchase, that would be greatly appreciated!

Here are my questions:

1. Does the Omax A195K-CA Kohler illumination unit https://omaxmicroscope.com/a195k-kohler ... copes.html fit on the Amscope T490B-LED microscope? I feel like the Omax microscopes that integrate the A195K-CA unit (especially the M837TL https://omaxmicroscope.com/40x-1600x-tr ... evice.html) are sufficiently similar to the Amscope T490B-LED that it might fit. Does anyone have any experience with this or happen to have these two pieces of equipment and would be willing to try it out for me? I feel like being able to upgrade to Kohler illumination down the road could be a very big plus, so I don't really want to be stuck without that capability. Unless, of course, you all think it rather unnecessary.

2. The user manual and the company representatives tell me that the LED bulb on the T490B-LED will not need to be replaced. While I recognize that LEDs last a very long time, I may never buy another microscope again. So while a 5 year warranty is comforting, I feel like it should be at least possible to access and replace the LED bulb in this scope. Does anyone have this microscope who can reassure me that the LED bulb is at least accessible? Will the Amscope BL-M148 replacement LED https://www.amscope.com/led-bulb-for-m1 ... -m158.html work in the Amscope T490B-LED? Are there other sources I could turn to for a replacement LED light?

3. The Amscope MD200 camera https://www.amscope.com/2-0-mega-pixel- ... amera.html seems like an awesome camera for microphotography/videography. It is inexpensive, compact, and has a decent 2.0 megapixels. Surprisingly, Amscope also claims that this little guy can record 1080p video at 25fps. This seems completely unrealistic to me as the camera is currently listed at $69.99 and uses USB 2.0. So I emailed Amscope, and they told me the specs were correct. I still question this though. Can anyone confirm or deny the capabilities of this camera?

Additionally, as far as buying cameras go, at what megapixel threshold do you feel like image quality ceases to improve? Does anyone have any camera suggestions for making YouTube-quality content (1080p 25fps video)?

4. My last concern is rather political. Is the Amscope T490 a copy of the Olympus CH2 or any other big name brand microscope? I do have a bit of an ethical compass and I'm struggling to accept that these companies might be more or less copying their more "prestigious" competitors.


Because some of the answers to these questions might not be what I want to hear, I see one of my possible backup scopes being the Omax M8311-CA https://omaxmicroscope.com/40x-2000x-tr ... piece.html. While this scope is much less appealing to me visually, I think it is compatible with the A195K-CA Kohler illumination device, darkfield condensers, and a phase contrast kit all from Omax. I feel like Omax has less of a user-friendly website and their scope-part compatibility leaves me uneasy. If anyone is aware of the Omax M8311-CA not being compatible with the darkfield condensers, phase contrast kits, or Kohler illumination device offered by Omax, please let me know.

Thank you!

Scarodactyl
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Re: Amscope T490 Questions

#2 Post by Scarodactyl » Wed Feb 10, 2021 3:25 am

In response to question 4, Olympus started out by copying Zeiss, and all major microscope makers are keenly aware of what the others are making. Plus the BH2 line is from the 80s, and any relevant patents are long expired.

natedoggraymond
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Re: Amscope T490 Questions

#3 Post by natedoggraymond » Wed Feb 10, 2021 6:51 am

Scarodactyl wrote:
Wed Feb 10, 2021 3:25 am
In response to question 4, Olympus started out by copying Zeiss, and all major microscope makers are keenly aware of what the others are making. Plus the BH2 line is from the 80s, and any relevant patents are long expired.
Thank you very much! This eases my conscience!

dtsh
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Re: Amscope T490 Questions

#4 Post by dtsh » Wed Feb 10, 2021 1:48 pm

natedoggraymond wrote:
Tue Feb 09, 2021 8:40 am
Hey all! This is my first post on the forum, so excuse me if I have done something bothersome by starting a new topic or posting in the wrong section. Any advice would be welcome!

I have been shopping for my first microscope for some time now and have narrowed it down to a few scopes. My goals with microscopy are discovery, personal research, and microphotography/videography. I seek to look at, identify, and learn more about microbes of all kinds. I intend to begin with the somewhat larger pondwater protists. I am a young college student and a passionate biology major. I could see my career or some of my research coming out of my experience with microscopy. It is certainly something I love. I have been greatly inspired by the work of James Weiss and Hank Green with Journey to the Microcosmos and dream of creating and/or experiencing content like theirs.
Check with your school for surplus! The schools around here retire the older, but entirely serviceable gear after some time and get new, so there's a good chance you can get a fairly high-end microscope of yesterday for not a lot of money.
natedoggraymond wrote:
Tue Feb 09, 2021 8:40 am
2. The user manual and the company representatives tell me that the LED bulb on the T490B-LED will not need to be replaced. While I recognize that LEDs last a very long time, I may never buy another microscope again. So while a 5 year warranty is comforting, I feel like it should be at least possible to access and replace the LED bulb in this scope. Does anyone have this microscope who can reassure me that the LED bulb is at least accessible? Will the Amscope BL-M148 replacement LED https://www.amscope.com/led-bulb-for-m1 ... -m158.html work in the Amscope T490B-LED? Are there other sources I could turn to for a replacement LED light?
In my family we have a saying, "What one man can put together, another man can take apart (and fix)". After a time everything wears out, it's unavoidable, but with a little time and ingenuity any broken part can be repaired or a replacement made. While LEDs are more complicated than a filament bulb, it should't be an impediment to replacement if you need to many years down the road. I upgraded one of my microscopes with a 10w LED recently and let me assure you, I'm no electronics guy. A friend helped me with the circuit and component selection and I put it all together.
natedoggraymond wrote:
Tue Feb 09, 2021 8:40 am
4. My last concern is rather political. Is the Amscope T490 a copy of the Olympus CH2 or any other big name brand microscope? I do have a bit of an ethical compass and I'm struggling to accept that these companies might be more or less copying their more "prestigious" competitors.[/b]
We'd get nowhere fast if we didn't copy each other. Patents exist to allow a company to manufacture a design with exclusive control *for a time*, but the trade off is that once that time is up, everyone gets it. Zeiss, AO, LOMO, all manufacturers build on prior art of those who got there before them.

natedoggraymond
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Re: Amscope T490 Questions

#5 Post by natedoggraymond » Thu Feb 11, 2021 9:04 am

dtsh wrote:
Wed Feb 10, 2021 1:48 pm
Check with your school for surplus! The schools around here retire the older, but entirely serviceable gear after some time and get new, so there's a good chance you can get a fairly high-end microscope of yesterday for not a lot of money.
That's a very good idea! Would you recommend checking with universities or high schools?
dtsh wrote:
Wed Feb 10, 2021 1:48 pm
In my family we have a saying, "What one man can put together, another man can take apart (and fix)". After a time everything wears out, it's unavoidable, but with a little time and ingenuity any broken part can be repaired or a replacement made. While LEDs are more complicated than a filament bulb, it should't be an impediment to replacement if you need to many years down the road. I upgraded one of my microscopes with a 10w LED recently and let me assure you, I'm no electronics guy. A friend helped me with the circuit and component selection and I put it all together.
I love that mindset! My only worry is that the LED is buried deep inside the microscope base and will be difficult to access. But, you're right, they had to get it in there somehow and therefore, I should be able to get it out. I also just feel like it would be so much easier if the LED were designed to be replaced and the company had spare ones for sale.
dtsh wrote:
Wed Feb 10, 2021 1:48 pm
We'd get nowhere fast if we didn't copy each other. Patents exist to allow a company to manufacture a design with exclusive control *for a time*, but the trade off is that once that time is up, everyone gets it. Zeiss, AO, LOMO, all manufacturers build on prior art of those who got there before them.
These are all very good points!

Thank you very much!

natedoggraymond
Posts: 37
Joined: Tue Feb 09, 2021 7:30 am

Re: Amscope T490 Questions

#6 Post by natedoggraymond » Mon Mar 08, 2021 8:36 pm

To those who care about my questions,

I purchased the Amscope T490B-LED (and have put lots of information on it and my experience with it here: https://www.microbehunter.com/microscop ... 24&t=12208). In the interest of building public knowledge about this scope and other Amscope and Omax products, I will attempt to answer some of my own questions.

1. The dimensions of the threads on the A195K-CA are given on the Omax website and it appears that the threads on the equivalent piece on the Amscope T490B-LED are much larger, thus deeming it incompatible. Additionally, the Omax A195K-CA has 32mm protruding below where the microscope base begins and the T490B-LED has much less than 32mm of clearance.

2. The LED assembly is accessible through the bottom of the microscope base. It looks nothing like the Amscope BL-M148 as there are multiple LEDs. I do not know as of yet if there is a way to upgrade this LED system, although it looks like someone with some electrical knowledge could do so.

-Nate
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PeteM
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Re: Amscope T490 Questions

#7 Post by PeteM » Mon Mar 08, 2021 10:27 pm

I'm curious about the LED version of the Amscope T490. Would it be possible to take a more complete pictures of the LED assembly? It looks like there are three glass tubes - different than most LEDS I'm familiar with. Can we assume there is also frosted plate between the illuminator to try and even out the light?

Have you tried taking photographs yet through the trinocular head? I'd be curious to know how even the illumination is.

Also, have they included an iris in the base?

The older T490 is one of the better yet affordable microscopes to get started with. Your update on the LED version will likely to of interest to many. Appreciate anything you can add.

hans
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Re: Amscope T490 Questions

#8 Post by hans » Mon Mar 08, 2021 10:44 pm

PeteM wrote:
Mon Mar 08, 2021 10:27 pm
Would it be possible to take a more complete pictures of the LED assembly? It looks like there are three glass tubes - different than most LEDS I'm familiar with.
The look like T-1 3/4 LEDs with clear domes to me, possibly seven of them arranged in a hexagonal pattern?

natedoggraymond
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Re: Amscope T490 Questions

#9 Post by natedoggraymond » Tue Mar 09, 2021 12:03 am

Great Questions! There is a frosted portion inside the removable black piece whose thread diameter I was discussing (the collector lens). I will take some more complete pictures of the LED assembly. It is difficult because there is a wire or two that prevents me from opening the LED access door very far. I will take some from above, having removed the black, threaded collector lens.

I have taken pictures through the phototube without issue and the illumination appears to be a bit less through the phototube. If I had to guess, I would put the perceived brightness at 60% through the binocular portion and 40% through the phototube when looking at both with one eye through a 10x eyepiece.

There is no iris in the base, but the LED brightness, is of course, variable. No Kohler possibilities here.

Pictures:
1. LED assembly viewed through door in base (wires impeding door from opening very wide). LEDs off.
2. LED assembly viewed from above, through the collector lens hole. Black, threaded collector lens removed. LEDs off.
3. LED assembly viewed through collector lens hole again. Black, threaded collector lens removed. LEDs on.
4. A more zoomed out view through the collector lens hole. Black, threaded collector lens removed. LEDs off.

-Nate
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natedoggraymond
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Re: Amscope T490 Questions

#10 Post by natedoggraymond » Tue Mar 09, 2021 12:06 am

More pictures:

1. The wires from the LED assembly and elsewhere plugging in to some part of the electrical system. Viewed through the collector lens hole, Black, threaded collector lens removed.
2. Black, threaded collector lens held up to the light to help visualize the frosting.
3. Black collector lens inserted. LEDs on.

-Nate
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natedoggraymond
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Re: Amscope T490 Questions

#11 Post by natedoggraymond » Tue Mar 09, 2021 12:07 am

hans wrote:
Mon Mar 08, 2021 10:44 pm
The look like T-1 3/4 LEDs with clear domes to me, possibly seven of them arranged in a hexagonal pattern?
Hans, you're right about the arrangement, but I'm not sure about the kind of LEDs.

-Nate

Greg Howald
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Re: Amscope T490 Questions

#12 Post by Greg Howald » Tue Mar 09, 2021 3:14 am

The led's appear the same shape and size of the one watt led bulb used in the Amscope m148 -150 series of monocular scope. If so a burned out bulb could be replaced with one of the spare bulbs which are available. I'm sure some soldering would be required. If those are one watt bulbs you are using 7 watts which should be really good illumination. The 490 is a sturdy and stable platform, well made and an Amscope top seller. Many accessories are available for it. Polarization is simple enough at under ten bucks. Dark field and phase contrast is readily available. The only thing I don't like about it is it's physical size. For me larger seems better. But that is just personal taste. You have chosen a good platform which will perform well, especially if you can figure out how to properly center the condenser.
Greg

natedoggraymond
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Re: Amscope T490 Questions

#13 Post by natedoggraymond » Tue Mar 09, 2021 7:25 am

Greg Howald wrote:
Tue Mar 09, 2021 3:14 am
The led's appear the same shape and size of the one watt led bulb used in the Amscope m148 -150 series of monocular scope. If so a burned out bulb could be replaced with one of the spare bulbs which are available. I'm sure some soldering would be required. If those are one watt bulbs you are using 7 watts which should be really good illumination. The 490 is a sturdy and stable platform, well made and an Amscope top seller. Many accessories are available for it. Polarization is simple enough at under ten bucks. Dark field and phase contrast is readily available. The only thing I don't like about it is it's physical size. For me larger seems better. But that is just personal taste. You have chosen a good platform which will perform well, especially if you can figure out how to properly center the condenser.
Thank you Greg! Do you have any tips for centering the condenser? It doesn't appear to me to be centerable.

-Nate

hans
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Re: Amscope T490 Questions

#14 Post by hans » Tue Mar 09, 2021 10:55 am

Would be interesting to know what LEDs those are. When I was looking at LEDs the T-1 3/4 ones I saw were limited to not much more than 20 mA due to high thermal resistance of the package. So even 7 of them at ~0.5 W total would still be less than the 3 W shown in the specifications.

natedoggraymond
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Re: Amscope T490 Questions

#15 Post by natedoggraymond » Tue Mar 09, 2021 1:51 pm

hans wrote:
Tue Mar 09, 2021 10:55 am
Would be interesting to know what LEDs those are. When I was looking at LEDs the T-1 3/4 ones I saw were limited to not much more than 20 mA due to high thermal resistance of the package. So even 7 of them at ~0.5 W total would still be less than the 3 W shown in the specifications.
Hmmm, suspicious. Do you think I could one day install like a 10W LED panel or something as a replacement?

-Nate

dtsh
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Re: Amscope T490 Questions

#16 Post by dtsh » Tue Mar 09, 2021 4:05 pm

natedoggraymond wrote:
Tue Mar 09, 2021 1:51 pm
hans wrote:
Tue Mar 09, 2021 10:55 am
Would be interesting to know what LEDs those are. When I was looking at LEDs the T-1 3/4 ones I saw were limited to not much more than 20 mA due to high thermal resistance of the package. So even 7 of them at ~0.5 W total would still be less than the 3 W shown in the specifications.
Hmmm, suspicious. Do you think I could one day install like a 10W LED panel or something as a replacement?

-Nate
I see no reason a person couldn't replace the supplied LED array with a different one; though you would likely need to replace the driver circuit as well. There looks to be plenty of room at least.

PeteM
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Re: Amscope T490 Questions

#17 Post by PeteM » Tue Mar 09, 2021 7:17 pm

Nate - thanks for the additional pictures and information on the LED version.

natedoggraymond
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Re: Amscope T490 Questions

#18 Post by natedoggraymond » Tue Mar 09, 2021 7:19 pm

dtsh wrote:
Tue Mar 09, 2021 4:05 pm
I see no reason a person couldn't replace the supplied LED array with a different one; though you would likely need to replace the driver circuit as well. There looks to be plenty of room at least.
Great! Thank you!

-Nate

natedoggraymond
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Re: Amscope T490 Questions

#19 Post by natedoggraymond » Tue Mar 09, 2021 7:20 pm

PeteM wrote:
Tue Mar 09, 2021 7:17 pm
Nate - thanks for the additional pictures and information on the LED version.
No problem!

hans
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Re: Amscope T490 Questions

#20 Post by hans » Tue Mar 09, 2021 9:44 pm

natedoggraymond wrote:
Tue Mar 09, 2021 1:51 pm
Hmmm, suspicious. Do you think I could one day install like a 10W LED panel or something as a replacement?
An interesting thing about the T-1 3/4 packages is that some have quite narrow beam angle around 15 degrees or less due to the relatively large diameter and longer focal length of the dome compared to the size of the die. That appears to be the case with the original ones judging by the large apparent size of the die and how it is already going out of view in the ones that are angled a little relative to the camera in the photo you took looking straight on. So the 3 W claim is a little suspicious, but just because I never came across higher-power ones doesn't mean they don't exist, and if they do it would be nice to know and find a source. Maybe someone with T490 or similar illuminator and DMM could measure the actual LED current?

As far as replacement, not obvious from your photos how strong the effect of the diffuser is. Would be interesting to hold a sheet of paper just below the condenser to see the size of the spot produced the LEDs and diffuser together. If the light is concentrated fairly well on the condenser aperture then substituting a large chip-on-board array could be quite a bit less efficient (require much more power to get the same amount of light into the condenser) because the light from the COB might be spread out over a larger angle with most missing the condenser. Of course COB arrays are available at such high power levels that you probably could end up with significantly brighter illumination by brute force, but at some point cooling becomes difficult.

The basic arrangement of the illumination in the Reichert-Jung 150 I have (also a student-oriented model) is similar to these and the Swift 380. The original bulb is a 6 V, 15 W halogen with integrated cold reflector to concentrate the light, followed by a mild diffuser with blue tint in the base below the condenser. The original bulbs are no longer available at reasonable prices so I was considering bypassing the electronics and substituting the more common 12 V, 20 W reflector bulbs but if higher-power T-1 3/4 narrow-beam LEDs exist that could be a nice alternative.

natedoggraymond
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Re: Amscope T490 Questions

#21 Post by natedoggraymond » Wed Mar 10, 2021 8:45 am

hans wrote:
Tue Mar 09, 2021 9:44 pm
An interesting thing about the T-1 3/4 packages is that some have quite narrow beam angle around 15 degrees or less due to the relatively large diameter and longer focal length of the dome compared to the size of the die. That appears to be the case with the original ones judging by the large apparent size of the die and how it is already going out of view in the ones that are angled a little relative to the camera in the photo you took looking straight on.
Ok, I'll be honest, I don't understand this entirely. But am I right that a narrow beam angle would be a good thing in this application?
hans wrote:
Tue Mar 09, 2021 9:44 pm
So the 3 W claim is a little suspicious, but just because I never came across higher-power ones doesn't mean they don't exist, and if they do it would be nice to know and find a source. Maybe someone with T490 or similar illuminator and DMM could measure the actual LED current?
I actually have a little DMM and measured the voltage to be 2.90 V for the whole array and each LED when the variable brightness was all the way up, but have no way of measuring Amps and therefore Watts. But if the voltage means anything to you, that's the reading I got.
hans wrote:
Tue Mar 09, 2021 9:44 pm
As far as replacement, not obvious from your photos how strong the effect of the diffuser is. Would be interesting to hold a sheet of paper just below the condenser to see the size of the spot produced the LEDs and diffuser together. If the light is concentrated fairly well on the condenser aperture then substituting a large chip-on-board array could be quite a bit less efficient (require much more power to get the same amount of light into the condenser) because the light from the COB might be spread out over a larger angle with most missing the condenser. Of course COB arrays are available at such high power levels that you probably could end up with significantly brighter illumination by brute force, but at some point cooling becomes difficult.
This makes good, logical sense. Thank you for the input!
hans wrote:
Tue Mar 09, 2021 9:44 pm
I did take some pictures of how the light diffuses, but I will say that this is a hard phenomenon to capture with a camera and I would say that the picture makes the light look more concentrated that it appears in real life.
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Greg Howald
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Re: Amscope T490 Questions

#22 Post by Greg Howald » Wed Mar 10, 2021 2:03 pm

Centering the condenser.
Many condensers on Amscope equipment can be centered with some difficulty even though instructions for that are not given. To see if it can be centered, remove the condenser and examine the condenser holder. Many consist of a ring of metal inside the casting. That ring is usually a little loose. The ring is usually a complete circle and the condenser slides up inside the ring and is held in place by a locking screw that goes all the way through both the outer and inner rings and the pressure of the screw pushing on the condenser is what actually holds it in place.
If that is the type of condenser holder you have then it can be centered. The inner ring is held in place by three very small Allen screws. Those three screws are the means of centering. You can go to the hardware store and buy three Allen wrenches to stick in there to adjust the screws and fumble with it a lot, or in the special screw selection that is in all those plastic boxes on the shelf you can pick up three gun screws about one inch long. Replace the Allen screws one at a time So things don't fall apart and then you have three screws sticking out that are nice and solid and easy to work with to center the condensing ring. Ok, so it's an involved process, but worth it. Be sure that when you mount the condenser to center it you tighten the lock screw only enough to hold the condenser in place . if that screw is too tight is will lock everything in place and you won't be able to center the condenser.
Greg

hans
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Re: Amscope T490 Questions

#23 Post by hans » Thu Mar 11, 2021 1:07 am

natedoggraymond wrote:
Wed Mar 10, 2021 8:45 am
...am I right that a narrow beam angle would be a good thing in this application?
Just speculating, but the design does look like it could be optimized with a relatively narrow beam from the LEDs in mind. What is the distance from the LEDs to the diffuser/lens?
natedoggraymond wrote:
Wed Mar 10, 2021 8:45 am
I actually have a little DMM and measured the voltage to be 2.90 V for the whole array and each LED when the variable brightness was all the way up, but have no way of measuring Amps and therefore Watts. But if the voltage means anything to you, that's the reading I got.
Yeah that is a normal forward voltage for a single LED, doesn't tell much except that the LEDs are in parallel. There is probably a resistor somewhere in series with the array, either for current sensing or current limiting depending on the design of the driver, which you could measure the voltage across to determine current. But understandable if you don't want to tear into your new microscope too much...
natedoggraymond wrote:
Wed Mar 10, 2021 8:45 am
I did take some pictures of how the light diffuses, but I will say that this is a hard phenomenon to capture with a camera and I would say that the picture makes the light look more concentrated that it appears in real life.
Yeah does look pretty well concentrated in the photo.

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Re: Amscope T490 Questions

#24 Post by natedoggraymond » Fri Mar 12, 2021 9:15 am

Greg Howald wrote:
Wed Mar 10, 2021 2:03 pm
Centering the condenser.
Many condensers on Amscope equipment can be centered with some difficulty even though instructions for that are not given. To see if it can be centered, remove the condenser and examine the condenser holder. Many consist of a ring of metal inside the casting. That ring is usually a little loose. The ring is usually a complete circle and the condenser slides up inside the ring and is held in place by a locking screw that goes all the way through both the outer and inner rings and the pressure of the screw pushing on the condenser is what actually holds it in place.
If that is the type of condenser holder you have then it can be centered. The inner ring is held in place by three very small Allen screws. Those three screws are the means of centering. You can go to the hardware store and buy three Allen wrenches to stick in there to adjust the screws and fumble with it a lot, or in the special screw selection that is in all those plastic boxes on the shelf you can pick up three gun screws about one inch long. Replace the Allen screws one at a time So things don't fall apart and then you have three screws sticking out that are nice and solid and easy to work with to center the condensing ring. Ok, so it's an involved process, but worth it. Be sure that when you mount the condenser to center it you tighten the lock screw only enough to hold the condenser in place . if that screw is too tight is will lock everything in place and you won't be able to center the condenser.
Greg
Greg! This is fantastic news and a very thorough explanation. Thank you! The gun screw idea is wonderful! How do I go about centering the condenser? Remove the eyepiece and close the condenser aperture and try to get the bright circle in the center of the field of view? How will I know when my condenser is properly centered?

Thank you!
-Nate

natedoggraymond
Posts: 37
Joined: Tue Feb 09, 2021 7:30 am

Re: Amscope T490 Questions

#25 Post by natedoggraymond » Fri Mar 12, 2021 9:22 am

hans wrote:
Thu Mar 11, 2021 1:07 am
Just speculating, but the design does look like it could be optimized with a relatively narrow beam from the LEDs in mind. What is the distance from the LEDs to the diffuser/lens?
It is hard to be exact, but about 45mm
hans wrote:
Thu Mar 11, 2021 1:07 am
Yeah that is a normal forward voltage for a single LED, doesn't tell much except that the LEDs are in parallel. There is probably a resistor somewhere in series with the array, either for current sensing or current limiting depending on the design of the driver, which you could measure the voltage across to determine current. But understandable if you don't want to tear into your new microscope too much...
Ah, interesting, I don't think I want to take the base off, but I am curious.. It would be awesome to upgrade it. Thank you for your wisdom!

-Nate

Greg Howald
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Joined: Tue Oct 20, 2020 6:44 am

Re: Amscope T490 Questions

#26 Post by Greg Howald » Fri Mar 12, 2021 11:53 am

Dear Nate. You are correct so far as centering is concerned. I've also tried using a 5x eyepiece and had success with a centering telescope. The simple rule is this. If it looks to be on center, it is.
Greg

natedoggraymond
Posts: 37
Joined: Tue Feb 09, 2021 7:30 am

Re: Amscope T490 Questions

#27 Post by natedoggraymond » Fri Mar 12, 2021 7:45 pm

Greg Howald wrote:
Fri Mar 12, 2021 11:53 am
Dear Nate. You are correct so far as centering is concerned. I've also tried using a 5x eyepiece and had success with a centering telescope. The simple rule is this. If it looks to be on center, it is.
Greg
Thank you again!

sheaney
Posts: 4
Joined: Fri Mar 19, 2021 11:37 am

Re: Amscope T490 Questions

#28 Post by sheaney » Fri Mar 19, 2021 1:11 pm

natedoggraymond wrote:
Tue Feb 09, 2021 8:40 am
I have been shopping for my first microscope for some time now and have narrowed it down to a few scopes. My goals with microscopy are discovery, personal research, and microphotography/videography. I seek to look at, identify, and learn more about microbes of all kinds. I intend to begin with the somewhat larger pondwater protists. [...] I have been greatly inspired by the work of James Weiss and Hank Green with Journey to the Microcosmos and dream of creating and/or experiencing content like theirs.

Basically, I'm looking for a microscope that is EXPANDABLE. I think darkfield, phase contrast, polarized light microscopy, Kohler illumination, microphotography, and all of the fun bells and whistles of this hobby are very appealing. Thus, I would like my first microscope to be one that, while not breaking the bank, can take me decently far with later upgrades and add-ons.
Hi natedogg and all, Thanks for this fascinating discussion! It's just what I have been looking for.

I too am shopping for first scope and am at a similar stage to where you were at, Nate, at time of OP. I too, I find Journey to Microcosmos inspiring and want to capture video. I am considering the 20W halogen T490A-DK darkfield version. How have you managed to get on with polarisation, or have you got to that point yet? I am aiming to try out, along with standard brightfield, oblique and darkfield (for microbes) but polarisation is also an important part as I want to study and capture birefringent crystals too. I note, however, that this scope is 160 fixed mechanical tube length, which presents some problems for polarisation?

sdsdfdsf
Greg Howald wrote:
Tue Mar 09, 2021 3:14 am
Polarization is simple enough at under ten bucks. Dark field and phase contrast is readily available. [...] You have chosen a good platform which will perform well, especially if you can figure out how to properly center the condenser.
Greg
Greg, you seem to be confident that polarisation can be achieved easily and cheaply with this scope. Would you mind elaborating on your experience?
Best wishes
Stuart

Greg Howald
Posts: 1185
Joined: Tue Oct 20, 2020 6:44 am

Re: Amscope T490 Questions

#29 Post by Greg Howald » Fri Mar 19, 2021 1:59 pm

Polarizing sheets are readily available from Amazon and other places. Cut them in circles of the right diameter. One goes in in between the head and the body of the scope. One on the illuminator. Rotate the one on the illuminator to adjust the degree of polarization. Some polarizers are linear and work in any position. Some are circular polarized and those are one way. Hold the two filters stacked together up to a light to orient them before installation. There's nothing to it really. Oliver Kim has made a you tube video on simple polarization. It's a great reference.
Have fun. Greg

sheaney
Posts: 4
Joined: Fri Mar 19, 2021 11:37 am

Re: Amscope T490 Questions

#30 Post by sheaney » Tue Mar 23, 2021 4:20 pm

Greg Howald wrote:
Fri Mar 19, 2021 1:59 pm
Polarizing sheets are readily available from Amazon and other places. Cut them in circles of the right diameter. One goes in in between the head and the body of the scope. One on the illuminator. Rotate the one on the illuminator to adjust the degree of polarization. Some polarizers are linear and work in any position. Some are circular polarized and those are one way. Hold the two filters stacked together up to a light to orient them before installation. There's nothing to it really. Oliver Kim has made a you tube video on simple polarization. It's a great reference.
Have fun. Greg
Thanks Greg, in terms of generally adapting a microscope, I have looked into this (I favour linear polarising) and have seen the Microbehunter video on home made polarising, among other sources I have looked at. What I want to know is more specific to this microscope: is the only way to do polarising with this microscope to hack it? Does this hack not present problems with the fixed tube length? Here is a quote from a page on Nikon Microscopy U:
Adding optical accessories into the light path of a fixed tube length microscope increases the effective tube length to a value greater than 160 millimeters. For this reason, addition of a vertical reflected light illuminator, polarizing intermediate stage, or similar attachment can introduce spherical aberration into an otherwise perfectly-corrected optical system. During the period when most microscopes had fixed tube lengths, manufacturers were forced to place additional optical elements into these accessories to re-establish the effective 160-millimeter tube length of the microscope system. The cost of this action was often an increase in magnification and reduced light intensities in resulting images.
Being of a more modern design, does the T490's optical system compensate for this? I would think to do polarising properly you would need an incident light intermediate tube - I'm guessing the T490 does not have the option to upgrade with this accessory?

Also, as you mentioned it is adaptable for polarising, I thought you meant it was actually designed to upgrade by fitting official adapters/filters (ie have a slot to insert dedicated polarising filters both after the nosepiece and (rotatable) in the condenser, be possible to add Bertrand lens, etc), rather than not be designed for the purpose and there is a hack to get around the limitation.

No worries, if you don't know the answer to all this, your kind help is much appreciated even so! :D I tried contacting Amscope before, some time ago and nobody replied. I can always try again.

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