Trouble seeing through eyepieces on trinocular microscope - Page 1
Forum section: electronics / testgear

author: gaminn
author_rank: Frequent Contributor
timestamp: April 11, 2025, 10:34:35 am
content: Hi, I purchased Chinese trinocular microscope and no matter how I adjust eyepieces I'm not able to comfortably see the image through eyepieces. I even 3D printed extensions that make eyepieces sligthly longer and it improved the issue, but it still difficult to use the eyepieces.This is the issue: I'm able to position my head and I see image from both eyepieces when my eyes focus on the centre of the image. But when my eyeballs move just a little bit to see and focus on the edges of the image, I immediatelly loose one or both images (the images/images is fully or partly black). I have to reposition my head slightly to be able to focus on the edges. It is incredibly hard to e.g. solder under the microscope because I constantly loose the image once I move my eyeballs or my head just sligthly so I have to focus on constantly repositioning my head instead of focusing on what I do under the microscope.I don't know if this is normal or I just don't know how to use the microscope. I disassembled the cover of the microscope and I can see that the black tape with round hole on the prism are misaligned with each other. Is that OK?The other issue I have is with the camera port - the only way to have sharp image coming from the camera is when I tilt my PCB (or whatever planar object I have under the microscope) by slight angle - I guess it is this phenomenom -https://eleshop.eu/knowledgebase/greenough-EN/. Is it possible to somehow limit this issue? Are there trinocular microscopes where camera image is sharp without tilting the object under the microscope?

author: sanderb
author_rank: Contributor
timestamp: April 11, 2025, 03:34:17 pm
content: Did you adjust the distance between the eyepieces, to make it match your eye's pupil distance? What you describe is what I typically have when it is not set right.

author: DaJMasta
author_rank: Super Contributor
timestamp: April 11, 2025, 03:52:23 pm
content: I agree that finding the right interpupillary distance is probably at least part of the problem with seeing only one image in an eye, usually this means rotating the body of the eyepiece prism area (from the outside) on a microscope with this kind of look. It can be hard to keep still enough to stay lined up with the scope and stay in that centered area all the time, but making sure the eye distance (and rotation angle) is right helps a lot. Otherwise making sure the scope is setup in a place you're not having to crane your neck to use will make it easier to stay still enough to stay with both eyes centered. The prism alignment could be an issue, but are both of them tilted inward in your image, or is just the left one? I can't tell whether it's uneven or whether they're just rotated evenly inwards. I would expect this to cause issues with focusing between the eyes (maybe less of the left eye image is in focus) if there is a discrepancy between them, but if I'm understanding it right, could maybe contribute to the problem you're describing.Does your trinocular port have a focus adjustment? Otherwise, do you have any spacer rings to adjust the distance to the focal plane of your camera? If you can find focus through your camera but when it's in focus the eyepieces aren't focused (or vice versa), you probably just need to adjust the distance from the port lens to the camera sensor, and since this is not necessarily standardized between camera systems, it could be that a little shimming or adjusting could be required.

author: mikes
author_rank: Regular Contributor
timestamp: April 11, 2025, 04:06:00 pm
content: Folding down the eyecups may help. Blacking out when off-axis can be due to short eye relief.

author: jfiresto
author_rank: Frequent Contributor
timestamp: April 11, 2025, 05:13:48 pm
content: Quote from: gaminn on April 11, 2025, 10:34:35 amThat may be the microscope's not-really-widefield eyepieces. I plopped a pair of stencil WF-10X/20 eyepieces in my stereo microscope (they could be the same as yours) and also had trouble keeping from clipping the view. Admittedly, I was standing before the microscope, which doesn't help, but then I went back to a pair of Olympus WHS10X-H/22 eyepieces and found it was considerably easier to keep my eyes on the work. The entire field was also in better focus, enough so that I could notice the mild perspective distortion of the microscope's objective.QuoteYes, the objective of either a CMO (Common Main Objective) microscope or a non-stereo macroscope stands perpendicular to the work and doesn't have that issue. Since there is just one lens, it is also common with either type to add at least another element: for a flatter, more widely sharper view (spherically, chromatically or both). A CMO microscope does have a possible issue which a fellow and I were discussing on another thread. I have been distracted by a project, but will try to post something interesting tomorrow.EDIT:"spherically and possibly chromatically" --> "spherically, chromatically or both"

author: thm_w
author_rank: Super Contributor
timestamp: April 11, 2025, 11:05:41 pm
content: Correct location for this thread is here:https://www.eevblog.com/forum/reviews/you can move it.Quote from: phansel on April 11, 2025, 04:21:17 pmEakinsQuote from: jfiresto on April 11, 2025, 05:13:48 pmThe difference between 10x20 and 10x22 is not significant, its just a bit wider FOV (which is nice admittedly).WHS10X-H/22 are highpoint objectives for use with glasses, so that might help if OP is wearing glasses.gaminn: didn't mention if they are wearing glasses or not, try to remove the glasses if you are, you have to find the right vertical height for your eyes.

author: Smokey
author_rank: Super Contributor
timestamp: April 11, 2025, 11:58:50 pm
content: I have a much harder time keeping my head aligned with the eyepieces without eyecups.Make sure the scope if parallel to the surface and that the eyepiece to eyepiece focus is set correctly. One of the eyepiece holders should have independent focus. Make sure both eyes are focused at the same time.

author: jfiresto
author_rank: Frequent Contributor
timestamp: April 12, 2025, 08:57:03 am
content: Quote from: thm_w on April 11, 2025, 11:05:41 pmBoth the WF-10X/20 (the OP's and mine) and WHS eyepieces should be or are high eyepoint. The WHS eyepieces are also plan and project a flatter field. That may be the deciding difference. If anyone wants to experiment, I can see if I can find a link to some competent Chinese eyepieces I bought last year that copy an old, Zeiss high eyepoint, flat field design.

author: watchmaker
author_rank: Unknown
timestamp: April 13, 2025, 12:14:15 pm
content: Quote from: gaminn on April 11, 2025, 10:34:35 amGaminn,I sold maybe 50 AO, Olympic, Nikon and Bausch zoom scopes to watchmakers including some with the trinocular attachment.What you are describing to me sounds like one or more prisms have been knocked out of alignment. This is not something you can repair yourself.In evaluation of a new scope, first set the fixed eyepiece to focus at low mag. Now set the adjustable eyepiece. The target should be centered in the field of view. Now zoom to max. Repeat the first step and then go back down to minimum. Both eyepieces should remain in focus as you zoom (parfocal). Repeat the adjustments until satisfactory. During zoom, the target should remain centered.I returned any scope that failed to the seller (this was when the institutions were switching from optical to digital and scopes were plentiful and cheap).If this is a recent purchase, I would certainly contact the seller. Hopefully there is a warranty or right of return. You should notnotneed extensions.I do have the user manuals for most optical scopes and all use the same procedures. I still have AO 580s at my soldering station, machine bench and inspection station. At one point, institutions paid $2K+ for these.FWIW, I wear glasses and use the scopes without them while my wife keeps her glasses on. I am near sighted and she is far sighted.

author: Smokey
author_rank: Super Contributor
timestamp: April 13, 2025, 08:39:00 pm
content: AO 580 shout out!

author: gaminn
author_rank: Frequent Contributor
timestamp: April 14, 2025, 10:03:12 am
content: Guys, thanks for all the replies.Quote from: mikes on April 11, 2025, 04:06:00 pmFolding the eyecups means my eyes/head is far from the eyepieces (aprox 0.5"). That's the reason I 3D printed eyepiece extensions. If I remove the extensions it is even harder to maintain good picture from the eyepieces.Quote from: thm_w on April 11, 2025, 11:05:41 pmI don't wear glasses.Quote from: jfiresto on April 12, 2025, 08:57:03 amOK, I'l try buying different eyepieces and see if it helps.Quote from: watchmaker on April 13, 2025, 12:14:15 pmNot sure which one is the fixed eyepiece and which one is the adjustable one. Both eyepieces are identical. I adjusted the distance between eyepieces, the focus adjusted on the individual eyepieces (dioptric compensation???), the zoom on the body of the microscope, focus of the microscope - which is adjusted by the distance of the object under the microscope from the microscope, I don't have any knob on the microscope which adjusts the focus. When I change the zoom, I have also to change the distance between object and the microscope. I don't know how to set my microscope so it maintains the focus while I change the zoom. That would be great featureQuote from: DaJMasta on April 11, 2025, 03:52:23 pm.I can always find focus through eyepieces, the whole image seen through eyepieces is sharp.I can adjust the focus/zoom of my cheap Chinese 0.35x c-mount adapter by the ring around the body of the adapter. I don't think shimming can help, please see attached pictures. Once the planar object lies horizontally under the microscope, part of the picture is always blurred (only left side of the picture is in focus). When I adjust the focus of the microscope (by adjusting zoom/focus on the c-mount adapter or by changing the distance between the object and the microscope, I can get another part of the image sharp. But never whole image. Only when the object is tilted by approx 10° or 15° then the picture is perfectly sharp.

author: jfiresto
author_rank: Frequent Contributor
timestamp: April 14, 2025, 10:52:22 am
content: Quote from: gaminn on April 14, 2025, 10:03:12 amHe is describing later designs that tight manufacturing control made possible. On yours, the song and dance would be:set both diopter adjustments to their zero settings, if they show them, or what might be around zero, if they do notleave the eyepieces alone and zoom in to maximum magnificationuse the main rack-and-pinion focus to bring an object in focusdo not change the focus and zoom out to minimum magnificationadjust each eyepiece diopter adjustment to bring the eyepiece in focusdo not touch the focus of anything, zoom in again and see if the object stays in focus.You may have to iterate a little to settle on the parfocal settings.Once that is done, you can go to minimum zoom and adjust the camera height above the flange: to match the camera's focus to the eyepieces'.

author: gaminn
author_rank: Frequent Contributor
timestamp: April 14, 2025, 11:41:43 am
content: Quote from: jfiresto on April 14, 2025, 10:52:22 amWow, the feature is here! Thanks. I just didn't know how to setup my microscope correctly. I can now zoom from min to max and vice versa a always be in focus.Still, the issue I described in my initial post is not solved, it is not very comfortable to look through eyepieces. I constantly have to compensate the moves of my eyeballs by slight moves of my head to see the whole image. Otherwise it is partly or fully black. I never used any microscope before, maybe it is normal. And yes I tried to set correctly the distance between eyepieces.The issue with the partially blurred image (or fully focused image only when it is tilted by 10 or 15°) captured by the camera also exists. It would be nice if this can be solved somehow.

author: jfiresto
author_rank: Frequent Contributor
timestamp: April 14, 2025, 12:08:26 pm
content: Quote from: gaminn on April 14, 2025, 11:41:43 amThat and the associated keyhole distortion are inherent aspects of the microscope's Greenough design. The two v-angled objectives you show, two images up, have to look at the object from different angles to produce a stereo image. You probably want a CMO design I mentioned earlier, with a higher order objective (plan or semi-plan) if you are after a flat image in uniform focus across the field of view. Here are the optical paths of a semi-plan CMO:

author: Psi
author_rank: Super Contributor
timestamp: April 14, 2025, 12:50:48 pm
content: Quote from: Smokey on April 11, 2025, 11:58:50 pm+1 for this. Eyecups needed and the rubber needs to be poking out not folded over.Also there are 3 focus controls, each eyepiece has one + the master focus knob.If you have eyepieces focus cranked hard one way and then correct this using the master focus knob you can get some odd effects.You can also get odd events unless you DO do that. i.e there's a sweet spot and the location of it can be a bit different from one unit to another. Try set both eye pieces to one extreme, then focus using master focus knob. Then try at the other extreme, Then try in the middle. See if the problem gets better/worse. If it does, try seeking for the ideal eyepiece focus position.But it does kind of sound like there's could be something wrong with your unit. Maybe a lens was installed the wrong way around or accidently left out. Also, they can get dropped during shipping and lenses can move out of alignment.

author: thm_w
author_rank: Super Contributor
timestamp: April 14, 2025, 10:09:43 pm
content: Quote from: gaminn on April 14, 2025, 11:41:43 amIts normal to some degree, usually you move the item itself around so that what you want to focus on is in the center of the image. You'll still see the outer parts of the image in your peripheral view, but not look at them directly.You can try capturing an image with your phone from each eyepiece, when the image is as large as possible on your phone (this will be a hard to hold steady). And both eyes should be about the same.