Stereo Microscope, Trinokular vs. Simul Focus: optical quality? - Page 1
Forum section: electronics / beginners

author: hirada
author_rank: Regular Contributor
timestamp: September 30, 2020, 08:57:52 pm
content: Has anybody experience with both a trinokular and a simul focal stereo microscope of similar make? Or some knowledge of the internals?I am wondering, when operating either without any camera attached, are there any differences in the image quality to be experienced? As the simul focal may (or may not, that's the question) have additional elements like prisms in the optical path to archieve that 3 beam split?Like a barlow affects image quality, even if small.

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 01, 2020, 07:43:39 am
content: A microscope that shares the view of an optical path between the eyepiece and camera (your "simul focal?), typically uses a 50:50 beam splitter which should transmit at least 45% of the light to the eyepiece and 45% to the camera. The other optical path also gets one, or a neutral gray filter, so the eyepiece brightnesses match.Fancier microscopes let you switch out the beam splitter(s)/filter and direct 100% of the light to both eyepieces.EDIT:To finish my interrupted answer, the beam splitters will introduce some aberrations if the beams diverge. I have no idea by how much as I have only used cameras on infinity corrected microscopes.

author: hirada
author_rank: Regular Contributor
timestamp: October 01, 2020, 10:23:59 am
content: Quote from: jfiresto on October 01, 2020, 07:43:39 amThat is an interesting statement, as usually the non switchable (the simual focals) are considered to be the fancier ones and are more expensive and sought after, even though the switchables should have a better optical image quality.

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 01, 2020, 10:37:46 am
content: Quote from: hirada on October 01, 2020, 10:23:59 amCould you be thinking of microscopes that only give you the choice of either using just one eyepiece and the camera or both eyepieces and no camera?The microscopes I am thinking of let you either use both eyepieces and the camera, all roughly half dimmed, or both eyepieces at full brightness and no camera. In addition to splitting the light 50:50 or 100:0, some microscopes used to have a third setting that sent 80% to the camera and 20% to both eyepieces: so that a lecturer using a video camera saw the same brightness as his or her audience.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 01, 2020, 11:13:51 am
content: If you plan to use the camera port a lot, then the choice is clear, get one in which some light is always going to the camera port.I bought an Eakins / Amscope / look alike, but with the left side switchable between eye and camera, and did this for the presumed higher light output.Price difference between not having the camera port was negligible, and this way have the option open to add an adapter to make some macro photos or a bit of video if I like.But it's the only microscope I have, so I can't compare.Also:Eyes are pretty much logarithmic and are usable for about 7 or 8 orders of magnitude. Halving the amount of light is just a few dB and probably barely noticeable.A thing that is noticeable is that you want much more light when zooming in with the microscope. Which is logical, cause when you look at a smaller area, the total amount of light that is reflected into the eyepiece is less, and it's surface area, so quadratic with the zoom factor.If you're a mechanical handyman without much money, then seriously think about making your own microscope stand. The separate microscope heads are not very expensive. The vertical focus is relatively expensive for what it does, and of barely adequate quality. The big boom stands are apparently of even less quality (multiple complaints about lineair ball bearings fretting into the tubes), and because of it's weight it's also expensive in shipping.If you buy some square lineair rails, and get some square steel or aluminum tubing you can make a much higher quality stand from it, and even if you pay yourself a day's salary it may still be cheaper.

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 01, 2020, 11:25:38 am
content: Quote from: Doctorandus_P on October 01, 2020, 11:13:51 amThis is one of my current projects using new parts sourced within Germany. I just need to find some scraps of hot rolled steel to practice using form taps and I can start cooking.

author: hirada
author_rank: Regular Contributor
timestamp: October 01, 2020, 02:39:00 pm
content: Quote from: jfiresto on October 01, 2020, 10:37:46 amYes, as far as I have understood, trinokular scopes have either both eyes and no camera, or one eye and a camera port, mode of operation changed by a switch. Simul focal have always both eyes and a camerad port light. That is at least how all those amscope/fyscope/eakins etc. are advertised and the usual youtube influencer seem to go d'accord. Fine with me.However, if the camera is only rarely needed, because one does not intend to do any video content, I was wondering, wether the trinoculars would not be a better choice, as they are slightly cheaper and may offer a tad bit better quality, since most of the optics will be the same, but the beam will not be split (and the nd filter may be missing). That is what I am taking away form this thread. Quite helpful.Since a binocular would basically be fine with me as well, I am currently looking more into getting a used quality scope, as those china scopes have a reputation of good optics, but really bad machanics, but I am not sure wether I know enough of all the captchas and what to look out for to take that risk. If not, I'll prefer a trinocular to a simul focal.Making my own stand is unfortunately completely outside my capabilities. I would exchagne the tubes of the boom stand, but that's about it and I am more into articulated stands anyway.

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 03, 2020, 10:44:05 am
content: Quote from: hirada on October 01, 2020, 02:39:00 pmImagine a non-technical reseller of anad hoccopier of old microscope designs were to describe what he sells. I can well believe what they wrote.I could probably write pages untangling the astounding and nonsensical claims found in modern mass microscope marketing, for example, that a microscope is simul-focal. Simul-focal literally means all the images are in focus at the same time. Well,everycompetently designed and manufactured stereo microscope is that or else the imaging will suffer.What they often seem to mean and that you may want is that the microscope provides a simultaneous view. A trinocular microscope can be designed to do that: the camera port and both eyes can all view the specimen at the same time. Or it can only can be designed so that the camera and just one eye can view the specimen, and the other eye goes dark. The latter is sometimes a little less helpful because the eye gets, say, the right side view and the camera gets the left, so that the eye and the camera view slightly different areas of the specimen from different angles.You can take perfectly good stills or videos with a microscope that splits the light 50:50 between an eyepiece and the camera (simul-view) or that steals all the light from one eyepiece and sends it to the camera. People go either way. Sometimes they want or need to know exactly what the camera will capture; sometimes they want or need the extra brightness. The competence and care the designer and manufacturer take with the the microscope and camera is usually the deciding factor and makes the other differences insignificant.With that in mind, Louis Rossmann shows the camera images froma couple Chinese Greenough zoom stereo microscopes, one with a poorly executed camera port ("Amscope") and one with a better one ("Rossmann scope").For comparison, I have attached a 1080p video frame taken by a newish camera from a clean, used "Big Four" microscope that was inspecting fiber optic assemblies some 30 years. It is not a very good picture: the circuit board was tilted and only the center is in focus. (I had to return the camera.) You can see in the dust, however, the greater detail you can get even with a "routine" (low end) microscope when a company is competent and careful about its design and manufacture. If you are up for the adventure, you can get some really nice used microscopes for a small fraction of what they would cost, new today. But you need to be patient and willing and able to return things that do not live up to their description.

author: hirada
author_rank: Regular Contributor
timestamp: October 04, 2020, 10:19:08 am
content: Again, thanks very much for you indepth exlpanation. Higly appreciated.Quote from: jfiresto on October 03, 2020, 10:44:05 amAnd between those two principles I am looking for the one, that potentially has the bettervisualquality, as the camera would only be nice to have. Since the simul view has a beam splitter, probably similar to what a binoviewer for a [cyclops style] telescope does, I guess the switching solution would be the prefered one, if I eventually should decide go down that road.So for Mr. Rossmanns Amscope recommendations (as the "Rossmann scope" is not available any more), I would prefer the amscope SM-4TZ (switching) to the SM-4NTP (simul view). For me, visual is far more important, but given the price difference to a pure binocular one, it probably does not hurt to have the camera port as an option. Unless of course the lousy mechanics for the switch influences the visual optics... have not thought about that so far.

author: Psi
author_rank: Super Contributor
timestamp: October 04, 2020, 11:18:08 am
content: I've tried the normal and the Simul Focus version of the typical china microscope that most of us have.When it arrived the Simulfocus one seemed really bad in terms of optical alignment and no one wanted to use it.But then, for no apparent reason, it started working fine.My suspicion is that the simulfocus head we got has loose optics, maybe due to a drop at some point during shipping, and maybe the alignment shifts sometimes.So i'm not too sure what to make of it.but I can say the following.When the simulfocus version we have here isn't suffering that optical issue it seems just as good as the standard one with the little knob you pull out.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 04, 2020, 11:36:00 am
content: The trouble with your thinking is that you probably skip over the most important part, and focus on a (mostly) insignificant thing.Does a red car drive faster then a blue car?Most of the quality of a microscope is in a combination of the materials used, the accuracy with which the lenses are ground and aligned.From what I understood of the (Chinese) market of these things, is that each shop has a different scope, and lots of them are built from parts bought from the same manufacturers, and that is why they look all the same.But even if the parts come from the same factory, they may be batches with different accuracy for different prices etc.A part of the alignment is the alignment with which the light that comes out of the microscope fits with your eyes.If this is even a tiny bit off, then it's a similar effect to looking cross eyed.I do the alignment purposefully by alternatingly closing my left and right eye, and then mentally comparing the pictures I see. The edges of the circles in the microscope should be very similar.If you go search Ali for the lowest price scope, you probably also get the lowest quality one.Throw in EUR50 extra and you may have a better quality microscope, but it's a gamble either way.I decided to buy a microscope from one of the vendors that had the "amscope" logo on their pictures, but I do not know if it means much. It's still a gamble.The whole concept of "brand names" does not mean much in China apparently.For me, thegamble turned out well. I'm quite happy with my microscope.There probably are better microscopes around, but its more then adequate for what I use it for.0603 parts look like the size of match boxes, and your soldering tip about the size of a finger.I have not done it yet, but I think I could easily solder 0201 with it.Also:I bought mine with 2 barlow lenses. A 0.5x lens, and a 2x lens.The 2x lens is absolutely useless for electronics work, as it has much to big magnification, and work distance is pretty small. But I bought it still for looking at all kind of other things.With the 0.5x barlow lens, work distance is about 20cm and depth of field also increases (in the same proportion?)A (slight) problem with the 0.5x barlow lens is that because of this great working distance, the eye pieces are also very high. They are 46cm above the working surface of my desk, which means you have to sit straight behind it with a straight back to get your own eyes high enough. It does work okayish. It's not really tiring or anything like that, but it does feel a bit uncomfortable.I could use the microscope without a barlow lens. but then the underside is open and insides get dirty from solder fumes. (You can buy a glass plate which screws on to remedy that)Ideally for me would probably be a 0.7x barlow lens. You can also buy these lenses later as add-ons. They cost around EUR30.

author: jfiresto
author_rank: Frequent Contributor
timestamp: October 04, 2020, 12:29:41 pm
content: Quote from: hirada on October 04, 2020, 10:19:08 amYou are welcome.QuoteI have used both kinds and have seen little if any difference, other than one is twice as bright at the camera. I think you will find the image quality will be much more determined by the overall cost cutting that went into the design and production of the microscope. I would want to know what compromises were made to make a microscope cheaper and still good enough, rather than cheaper and not quite.

author: AlfBaz
author_rank: Super Contributor
timestamp: October 04, 2020, 01:37:43 pm
content: I had an amscope trinocular scope.It received a rather large knock and went out of alignment, impossible to use with both eyes.I purchased a replacement which is essentially the same head but simulfocal and there's no perceivable difference when looking through the lenses.As far as camera images both produce the same quality and brightness, having said that the camera I have is pretty shitty so perhaps a better camera might had picked up a difference

author: hirada
author_rank: Regular Contributor
timestamp: October 06, 2020, 11:31:18 am
content: Quote from: Doctorandus_P on October 04, 2020, 11:36:00 amThat is why I have referred to both variations of the same manufacurer, amscope, assuming that the quality (or lack thereof) may be the same for both types, with just the difference being one having a beam splitter and the other one a hole for rotating the prism (suspected). Amscope may be more expensive, but at least they have european support, something I would not expect from buying at ali.I am aware, that buying cheap chinese is always a risk, that (and for other reasons) is why I am still thinking of a used one as an alternative. But within that one manufacturer I was just interested, wether there are principal differences that could influence my decision, as most reviews I have gotten hold of refer to the convenience of the simul view, and maybe the quality of the camera, both of which are not important for me.I am aware, going that road is a gamble, as I can't influence or judge the build quality beforehand, I just can go for what may give me better chances.However, as stated here multiple times, there is no real visual difference between the two, so this is nothing to worry about and given the rather bad mechanical quality, misalignment due to tolerances in the switch may be a greater risk than using the beam splitter.That helped a lot.Thanks to all four your time, explanations and sharing of your particular experience

author: Nusa
author_rank: Super Contributor
timestamp: October 06, 2020, 02:46:39 pm
content: Realize that even if there is a loss of brightness after beam-splitting, that's solvable by simply providing more light. One also needs more light at higher magnifications. There's a reason the brightness is adjustable on microscope lights.