Chinese stereo zoom microscope: very precise head position needed w/ eyepieces? - Page 1
Forum section: electronics / testgear

author: TheBloke
author_rank: Contributor
timestamp: May 09, 2018, 07:41:16 pm
content: Hi allI tend to write a lot, so here's the quick summary of my question/issue:I just got my first stereo microscope, a trinocular zoomno-name Chinese modelwith single-boom stand, camera, LED ring and 0.5, 2.0and 0.3auxillary objectives. It's great, except I'm finding it harder than I anticipated to maintain a solid circular image in the eyepieces. It seems the slightest movement of my head or my eyes causes the image to narrow, go dark/black at the edges or double. It seems the required position of head and eyes relative to the eyepieces is incredibly small, smaller than I ever imagined. I've spent quite a lot of time adjusting the eyepieces and with a little practice of where and how to position my head, it's a bit better. But still not as easy and comfortable to use as I expected from watching others use them on YouTube.I don't know if this is common to these microscopes, or might be the result of my misconfiguration, or else a problem with my cheap(er) no-name Chinese device.I wanted a stereo microscope for repairs on SMD components such as laptop motherboards. I started out looking at Amscope, but my budget limited me to scopes such as the SE400-Z and I was really taken with the idea of getting a trinocular zoom microscope, ideally with a camera (which I figured would be preferable for general investigations with schematics/boardviews.)So I decided to do as I usually do and buy cheap no-name Chinese stuff. I foundthis packageon AliExpress. I got an especially good price - it's now listed as $595 / £446 but I paid only $410 / £300. Most gratifingly, the seller listed it at the wrong price (as she explained when I asked why it was removed from sale hours after my order) but still honoured my order.Mostly I'm really happy with and impressed by it. The picture, field of view and working distance are superb - not least considering that until now I've been using one of those awful $15 USB things. It's simul-focus, parfocal, and the camera is pretty good through HDMI at 60hz (albeit providing a narrower field of view than available through the eyepieces.)The only issue, as mentioned above, is my difficulty in maintaining a clear, consistent image through the eyepieces. I have to have my head and eyes in a very precise, small area in order to get a complete circular image. If my head moves even a couple of millimeters, or my eyes aren't completely central, the image narrows at the edges as one or other eye is no longer getting a full image. And I can't put my head/eyes fully up against the eye pieces, else I get tunnel vision. I have to hold my head a few millimeters back from the eyepieces.The result of all this is that it's somewhat uncomfortable to use for any period of time - I can't rest my forehead on the eye pieces, and I'm trying to hold my head back a few mm while also trying to hold it completely still and keep my eyes centered. Any minor deviations and the image quickly darkens or doubles.I've spent a long time tweaking the eyepieces - interpupillary distance and the diopters (adjustable on both eyepieces.) Adjustments and practice have made things better, but I still find it a little awkward to use.Maybe all stereo microscopes are like this? But that's not the impression I got when watching people use them in videos. Or maybe there's more adjustments I can make? Or maybe my 10x/20 eyepieces aren't the best? I could probably replace the eyepieces with Amscope branded ones, as I guess the fitting will be standard. I'd rather not spend more money, but will if it could definitely improve things.Here's a few photos (click for larger):As shown the eyepieces have a removable plastic ring at the bottom, and I'm yet to work out its purpose. it doesn't appear to affect how the eyepieces sit in the head. They rest on the bevelled edge you can see half way up, so the ring doesn't seem to affect their height or position in any way. I'm using the eyepieces with the eye guards attached, and that does help as they stick out a little way from the eyepieces and block out some light when I'm close in. I should add that I normally wear glasses, but am looking through the microscope without them because the viewing angles are even worse trying to use the scope with them on (even with the guards removed). I'm short sighted, but can read things up to 2-3 feet away, so the image through the microscope is clear enough without my glasses. But obviously my eyes aren't the best, with variable amounts of astigmatism in each eye, and I don't know if that affects things at all.As this is my first stereo microscope I hoped to check with more experienced users as to whether all this is normal or not. Any advice would be most appreciated. Thanks in advance.PS. if it makes any difference I'm currently testing with the 0.5 auxiliary objective/Barlow lens, which gives a good combination of working distance, zoom level and field of view. I also have a 0.3 Barlow which would further extend WD and FOV at the expense of zoom, or the option to operate at 1x with no auxiliary objective attached; I've not experimented with those options yet. I don't anticipate using the 2.0 objective for anything, at least not anything electronics related.

author: BillB
author_rank: Unknown
timestamp: May 09, 2018, 08:01:55 pm
content: I've got a very similar setup, only with Amscope (3.5-45X with .5X barlow), and while I can't offer any specific advice beyond the adjustments you've already been making, my experience was similar when I first got mine. I wear glasses, but my lenses to not touch the rubber eyeguards while I'm viewing. Over time, I got used to how my head needed to be positioned and now it's second nature and very comfortable.Tonight, when I am in front of it again, I'll try to take note of what I did adjustment-wise and how far away I am from the eyepieces. My first guess right now is that you might still need to adjust the interpupillary distance and/or you might be a little too close to the eyepieces.

author: _Wim_
author_rank: Super Contributor
timestamp: May 09, 2018, 08:09:13 pm
content: I have the same issue with my KYOWA SD-2P microscope (also a low-cost stereo microscope that I got for free without a stand). I also was expecting this to be much better, but have not yet had the change to compare it to a high end model. I also wear glasses, and use the microscope with an without.I only use this microscope when I want something with a higher magnification that my old Mantis (which is fantastic and very comfortable to use, but has a max magnification of 8x), so I never really looked into the issue deeply.

author: chris_leyson
author_rank: Super Contributor
timestamp: May 09, 2018, 08:55:13 pm
content: I've haven't used a stereo microscope since being made redundant from my last job nearly a year ago but it was sometimes hard work getting your head in just the right position. In my new job we've got an old Mantis which is great. You might want to look at wide field eyepieces or oculars and they might improve the situation. Standard microscope eyepiece diameter is 23mm sometimes 30mm which is a shame because I have a few telescope eyepieces but they are 31.75mm. I haven't saved up enough to buy a trinocular microscope but when I do I will have to find the nearest stockist and take a trip over there just to try things out.

author: BillB
author_rank: Unknown
timestamp: May 09, 2018, 10:31:39 pm
content: Ok, just sat in front of the scope again. I think what you are experiencing is completely normal. With the eyeguard rubber up, my glasses would touch; with the rubber folded down I am a little closer, but of course not touching.After you spend some time you will find your natural position, and you'll eventually become accustomed to it. I spend significant amounts of time on it and don't struggle at all finding/keeping the proper position.

author: TheBloke
author_rank: Contributor
timestamp: May 09, 2018, 10:47:43 pm
content: Quote from: BillB onTodayat 23:31:39OK, thanks very much for checking that for me. And to everyone else with the similar experiences.It's good to know there's likely nothing wrong with the unit I have. I'll just keep working with it and hopefully find that with time I get used to how to sit and what I can and can't do while using it. For example I'm thinking it's probably easier to move the target object (eg motherboard) around in the view rather than trying to move my eyes to see things at the periphery.Despite the learning curve it's definitely a lovely device to use and I'm loving the difference it makes. I didn't think having a stereo image would be all that big a deal but it makes a surprisingly big difference to how everything looks.Thanks again, all!

author: digsys
author_rank: Unknown
timestamp: May 10, 2018, 12:23:07 am
content: Same results as others -Amscope. Sometimes I get it perfect first try, other times it's like tossing and turning in bed .. never quite right.I did find some huge rubber eye-cups, which helped a lot, but still never perfect. So I guess it's normal.

author: TheBloke
author_rank: Contributor
timestamp: May 10, 2018, 12:34:36 am
content: Quote from: digsys onTodayat 01:23:07Thanks, larger eye caps sound like a good idea. Putting on the ones I have certainly helped and if I had ones that extended out further they might come to the right distance from the glass for holding my head, making it easier to repeatably return to that position and stay there.I'm guessing my scope is more or less a replica of Amscope. Certainly the specs and physical appearance all seem basically identical. Actually wouldn't surprise me if they're all made in the same factory. So anything meant for Amscope should work, and any Amscope accessories likely have Chinese copies anyway. I'll have a look around for bigger eye caps.

author: nanofrog
author_rank: Super Contributor
timestamp: May 10, 2018, 01:07:32 am
content: Quote from: TheBloke on May 10, 2018, 12:34:36 amThe brand/label doesn't matter. Just be sure you're ordering the correct size and you'll be fine.Some size info that might be useful to you:Barlow, filter, ring adapter = 48mmEye tube = 30mmThese ^ are inner diameters.For rubber eye guards/shields, just look for something that fits 32 - 33mm OD (they'll stretch a couple of mm if you need it).

author: TheBloke
author_rank: Contributor
timestamp: May 10, 2018, 02:50:56 am
content: Quote from: nanofrog onTodayat 02:07:32>Quote from: TheBloke onTodayat 01:34:36The brand/label doesn't matter. Just be sure you're ordering the correct size and you'll be fine.Some size info that might be useful to you:Barlow, filter, ring adapter = 48mmEye tube = 30mmThese ^ are inner diameters.For rubber eye guards/shields, just look for something that fits 32 - 33mm OD (they'll stretch a couple of mm if you need it).Lovely, thanks a lot.While looking for eye shields I've been looking through other eyepieces. I'm thinking I might try getting another pair, just to see how they differ at all. (OK and I like buying accessories..)I've found a couple of different and potentially interesting ones :WF10X/23mm Zoom Adjustable High Eyepoint Wide Angle Eyepiece 30mm- 23mm FOV vs my current 20. And adjustable in some way, not sure how? Does that mean the 10x zoom level is variable?SWF10X Field of View 23mm Super Wide Angle Optical Eyepiece 30mm- claim to be 'super widefield' vs 'widefield' (labelled SFW vs my current WF.) I'd thought widefield referred to FOV, ie the 20-23mm part? But maybe this means what I wanted, greater viewing angle through the eyepieces? Bit expensive for a pair.Also these, similar, slightly higher price.WF5X 20mm5x instead of 10x - I've been wondering what difference that makes in practice - eg the difference between having zoom 1x + 10X versus zoom 2x + 5X. I suppose it means lower FOV at the same zoom level. Don't know if lower magnification eyepieces might also have a more generous viewing angle?Not sure how much different eyepieces can affect the viewing angle issues I described, but regardless it might be interesting to try a different pair to see how they affect things, like maybe one of the 10x / 23mm sets just for the extra 3mm of FOV. Extra FOV is always nice. But I'd definitely be interested in the SFW ones if that does indeed affect my viewing angle.

author: jfiresto
author_rank: Frequent Contributor
timestamp: May 10, 2018, 08:54:20 am
content: A pair of adjustable eyepieces allow you to correct the focus of one eye to match the other ("diopter adjustment") and to focus the eyepieces to match the microscope. A microscope that is parfocal, projects an intermediate image inside each eye tube at a fixed distance into the tube – that doesn't change as you change the magnification. The focus of the fixed eyepieces that came with your microscope are set to the microscope's intermediate image so that the microscope stays in focus as you zoom in and out.The removable plastic ring you ask about shows you the depth of the intermediate image (assuming competent design). The ring holds an optional, measurement reticle at exactly that depth, so that the markings on the reticle are in focus, and remain in focus as you zoom in and out.To make life interesting, different microscope makers have different notions as to what depth to place the intermediate image. Unless a pair of eyepieces were specifically and accurately made for your microscope, or the original it copies, you likely want adjustable eyepieces so that you can move their focus to the microscope's intermediate images – and make the microscope parfocal. Alas, very few adjustable eyepieces let you move the reticle platform to the intermediate image to make a reticle useful.A pair of adjustable 10/23 eyepieces would be what I would go for – matching the microscope if you plan to use a reticle. Unless the microscope is poorly made, it should have enough resolution for 10X, which you can then reduce with your 0.3X auxilary objective to win working distance.

author: TheBloke
author_rank: Contributor
timestamp: May 10, 2018, 08:59:14 pm
content: Quote from: jfiresto onTodayat 09:54:20Thanks very much for all the details.My microscope head already has diopter adjustments in each eyepiece housing - a gnurled ring that turns the whole housing:So I'd assume that having the same adjustment on the eyepiece itself wouldn't really be necessary in this scope? I don't have any problem getting the microscope set up parfocally - it's in focus across the whole zoom range, achieved with minor adjustment on the diopters (I followedthis guide.)Regarding the plastic ring, are you saying that its only purpose is to hold an optional reticle? The ring serves no purpose unless such a reticle is installed? The reticles are transparent sheets, with a cross-hair or lines on them? I've seen those for sale. The rings don't seem to have any kind of lip inside, but I guess the reticle is exactly the right diameter to fit exactly inside the ring. I don't anticipate ever needing a reticle though (the camera can add one, and/or a grid of lines, to its digital image should it ever prove useful.)Currently I'm most drawn to those "super widefield" SFW 10x/23 eyepieces. I still don't fully understand if "super widefield" vs my current "widefield" does affect the viewing angle through the top of the eyepieces (as opposed to affecting the FOV of the sample under inspection.) I couldn't think what else it would be, given I thought the FOV was represented by the 23mm in the spec.Unless widefield/super widefield is simply a label describing FOV at a certain level? Like WF is 20mm, SWF is greater, and non-widefield is lower - something like that?In which case maybe the "super widefield" on these means nothing, it's only the FOV of 23mm that's important? But I wondered if it might be significant that they are specifically labelled SFW on the side, where most (including mine, and the Amscope originals) are labelled WF:

author: BillB
author_rank: Unknown
timestamp: May 10, 2018, 09:36:04 pm
content: The 23 number you are seeing is more likely the mounting size diameter.I wouldn't get hung up on super vs. non-super wide field. Amscope themselves use the term to describe 10mm, 15mm and 20mm fields of view.But, simply, you can tell you have a super wide-field set by looking at the size of the opening for the top lens. It is very big vs. the peep-hole opening that normal eyepieces have. Look at the Amscope eyepiece page and the difference will become clear.http://www.amscope.com/pair-of-super-widefield-10x-microscope-eyepieces-30mm.htmlhttp://www.amscope.com/pair-of-super-widefield-15x-microscope-eyepieces-30mm.htmlhttp://www.amscope.com/pair-of-super-widefield-20x-microscope-eyepieces-30mm.html

author: KrudyZ
author_rank: Frequent Contributor
timestamp: May 11, 2018, 01:56:14 am
content: How precisely you have to place your eyes to see a proper image is determined by the position and size of the exit pupil of the objective lenses.The microscope projects an image that needs to pass through the pupil of your eye to be seen.Sizing the exit pupil is a trade-off like anything in engineering.Making it small will create a bright image, but your eyes need to align well, while making it larger will allow for misalignment, but some of the light will be blocked by the iris of your eyes, creating a darker image.Placing the exit pupil farther away from the objective gives you some space that's useful if you wear glasses, but requires larger lenses, increasing cost.Placing it closer allows either for cheaper construction or better correction, but your eyelashes might sweep the front element with every blink.https://en.wikipedia.org/wiki/Exit_pupil

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 11, 2018, 02:10:55 am
content: I used a Nikon Labophot stereo microscope similar tothisfor years and had exactly the same experience especially at higher magnifications. Careful adjustment of the interocular distance helps. I don't think this is down to being Chinese.Somewhat OT, when I was about 9 I got a small microscope. Every now and then I'd see a huge image of my eyelashes - it scared the crap out of me. Suffice to say I overcame that fear (and of moths).

author: TheBloke
author_rank: Contributor
timestamp: May 11, 2018, 02:26:28 am
content: Quote from: KrudyZ onTodayat 02:56:14;https://en.wikipedia.org/wiki/Exit_pupilOh that's very interesting, thank you. So in fact the issue I'm having is really nothing to do with the eyepieces at all, but rather the optics below the eyepieces - the main objective, and any auxillary objectives?To test that - partially at least - I just tried removing the 0.5 auxillary I've been using exclusively, running the scope at 7-45x for the first time. And yes it definitely seemed more generous in terms of position of eyes and head. I don't know if I'm imagining it, but I also thought the image was a little brighter and 'cleaner'. I suppose that's perhaps not surprising - the fewer lenses in the path, the better.Unfortunately the working distance drops to only about 100mm / 4", and it's even lower with my LED ring in place. Not enough for comfortable soldering/desoldering I think. I could probably improve things by using a different light source. But I think I'll perservere with 0.5 for now, and try and get used to getting the position right.I suppose there's the possibility of getting a better/different 0.5 auxillary. Though it might be hard to find one guaranteed to be better, at least without spending significant money (ie. not from AliExpress.)I did see my eyelashes once this evening - well an eyelash shaped shadow anywayThat's cleared a lot up, thanks a lot.Quote from: BillB onTodayat 22:36:04;http://www.amscope.com/pair-of-super-widefield-10x-microscope-eyepieces-30mm.htmlhttp://www.amscope.com/pair-of-super-widefield-15x-microscope-eyepieces-30mm.htmlhttp://www.amscope.com/pair-of-super-widefield-20x-microscope-eyepieces-30mm.htmlThey're definitely 23mm FOV - the fitting is listed separately as 30mm.OK, so widefield/super is just a descriptive label for FOV. Thanks. I thought it might mean something in addition to that.I suppose those SFW eyepieces I listed are called 'super' just because they're 23mm versus 22mm. A pretty meaningless distinction I guess. They're also quite a lot more expensive without any obvious justification besides the extra mm. I might well get a pair of 10x/22mm though, they're affordable enough. Even if they're indistinguishable from my 10x/20's, it'd be good to have a spare set. They seem the most likely part to get damaged in general usage. I've already taken them out several times for cleaning.I'm also considering getting a 0.3x camera adapter. My scope package came with a 0.5x adapter, which results in the camera being zoomed in about 1.6x more than the eyepieces (ie equivalent to being 16x versus 10x). I read aquick guide on camera adapterswhich recommended a 0.3x for a camera with a 1/3" sensor, as mine has. And 0.5 / 0.3 = 1.66 is almost exactly the difference in zoom I see in the camera versus eyepieces, so I hope 0.3x will give me the same view through camera as eyepieces.Anyway, thanks again for your help, everyone.

author: jfiresto
author_rank: Frequent Contributor
timestamp: May 11, 2018, 07:00:45 pm
content: Quote from: TheBloke on May 10, 2018, 08:59:14 pmIt should be enough, but you might be unlucky and want just a little more adjustment. I have adjusted a pair of 10/22, high eye-point Olympus oculars off the scale and they are still not quite parfocal in my non-Olympus microscope. But I can live with the slight refocusing.QuoteYes. Assuming the magnification of your photoport and still+video USB camera is repeatable, you probably don't need a reticle.QuoteThat is how people generally understand it: at ten times total magnification, you will get a 23 mm field-of-view diameter. At some point as you increase its FOV, the eyepiece sees the entire intermediate image, and beyond that, it shows no more of your object. For the microscope before me, made by fastidious Swiss optical wizards, decades ago, that is somewhere around 10x/26mm, depending on what you stick in the optical path between the eye tubes and the objective.I struck the last three words from my earlier post: an 0.3x auxiliary objective, in total, largely wins you working distance. I find an 0.5x auxiliary objective, to get 3.2–20x, gives a good magnification range for the surface mount I do.