Reducing Microscope Working Distance - Page 1
Forum section: electronics / general

author: safarir
author_rank: Regular Contributor
timestamp: February 15, 2023, 02:31:05 pm
content: Hi All,I recently purchased a 0.65x to 6.5x microscope from aliexpress and I am using it with a 0x5 Barlow lens and standard 10x eyepiece. This give me a really nice 3.25x to 32.5x range which I really like. I temporary had a standard 0.7x to 4.5x microscope which I returned because I really did not like the double arm stand.One thing that is different with this new one is the crazy working distance, we are talking over 200mm. At first, I was really happy about that but quickly realize that there is some downside to this, mainly having hard time finding a comfortable position and mostly, the lighting problem.Having lens being so far from the work-piece mean the angle of the light is way smaller which create more glare. Simply holding the light about 50-80mm lower dramatically improve the image quality.I could simple 3d print a extension tube to lower the light, but if there is a way to reduce the working distance, without loosing my 3.25x range, that would be fantastic. So the question is: Is there a way to reduce a microscope working distance ? A other solution might be some kind of light diffuser or larger led ring, I waiting for your suggestions.Thank you

author: RoGeorge
author_rank: Super Contributor
timestamp: February 15, 2023, 02:50:06 pm
content: Remove the Barlow lens.

author: ygi
author_rank: Regular Contributor
timestamp: February 15, 2023, 06:21:35 pm
content: Working distance is a physical property of the lens that's usually written on it . If you wish to keep everything as it is except for the shorter distance, then you need to buy a 0.5x Barlow with a shorter WD (165mm is the most common on AE).

author: KE5FX
author_rank: Super Contributor
timestamp: February 15, 2023, 07:18:43 pm
content: Overvolt the ring light. They're cheap.You don't want todecrease your working distance. (edited, typo)

author: janoc
author_rank: Super Contributor
timestamp: February 15, 2023, 09:01:32 pm
content: Quote from: KE5FX on February 15, 2023, 07:18:43 pmOr just ditch it and replace it with one or two gooseneck lights from the side. Those are much better than a ring light shining perpendicularly to the board - that will produce glare no matter what. Ring lights are great for biology specimens but terrible for PCBs or anything reflective.

author: Psi
author_rank: Super Contributor
timestamp: February 15, 2023, 11:31:13 pm
content: Yep the barlow lens is what changes the working distance.You could also try a different height chair/desk. You may have optimized this for your old microscope working distance without even realizing.For my setup using 0.5 barlow. If I sit up straight at the microscope the center of the eye pieces is about at lip height.This seems to work great to lean in and use the microscope and i don't get a sore neck or anything.The surface of my desk is 75cm high off the floor

author: Electro Fan
author_rank: Super Contributor
timestamp: February 16, 2023, 04:08:25 pm
content: Quote from: Psi on February 15, 2023, 11:31:13 pm+1When researching microscopes lots of variables get considered, especially working distance and this leads to tradeoffs in Barlow lenses. For an optimum implementation it’s good to also consider where your eyes will be - and therefore whether you will be sitting or standing as you use the microscope, as this will influence the overall microscope implementation design including the height of the desktop or bench surface, and the particular chair or stool if you are sitting. If you will be primarily using the scope while sitting you will want to use a suitable height chair or stool with a desk or bench that allows for knee/leg clearance. Working distance is a key consideration but if you optimize for working distance along with the rest of the ergonomics - especially the preferred location of your eyes and the rest of your body you will probably get a better overall result.

author: safarir
author_rank: Regular Contributor
timestamp: February 17, 2023, 01:47:54 am
content: Quote from: RoGeorge on February 15, 2023, 02:50:06 pmNot really a option to do soldering, I need the 0.5x multiplier ...I will try with different light to see if I can get a acceptable result. I am starting to really appreciate the very long working distance: Being able to put the microscope over my pcbite probe have been really nice !

author: Psi
author_rank: Super Contributor
timestamp: February 17, 2023, 03:45:21 am
content: Yep, trying to solder without a 0.5 barlow is very annoying.Doable, but I'd take the barlow downsides any day.

author: HobGoblyn
author_rank: Unknown
timestamp: February 17, 2023, 10:39:06 pm
content: While I liked the large distance with the 0.5, I found to use it comfortably, I was having to stand (health doesn’t allow me to stand without being in pain)It was just a tiny bit too high with my desk setup.I changed to a 0.7 and for me, it’s been perfect

author: KaneTW
author_rank: Frequent Contributor
timestamp: February 17, 2023, 10:40:42 pm
content: Change the eye piece to reduce magnification, remove the barlow lens.

author: thm_w
author_rank: Super Contributor
timestamp: February 17, 2023, 11:10:33 pm
content: Ergonomically 240-250mm working distance would be good for me (with a standard amscope head). If I had to use 200mm or less I would need to slouch over, which is not good for your back/neck for long periods of time. I would prioritize your health.What is your current lighting setup?I disagree that ring light is not good for PCBs, I don't have any issues with reflections. BUT its probably going to be a lot harder to get a quality ring light that will handle that distance.Quote from: HobGoblyn on February 17, 2023, 10:39:06 pmInteresting.Maybe your desk is really high or your height/microscope is quite different from mine. What is the model?Quote from: KaneTW on February 17, 2023, 10:40:42 pmWhat is the FOV of a 5x eyepiece though? Usually its terrible compared to the 10X ones.

author: Psi
author_rank: Super Contributor
timestamp: February 18, 2023, 02:45:05 am
content: For refence regarding my previous comments, i'm using WF10x/20 objectives.I believe these are the typical ones you get by default. The WF stands for widefield

author: Smokey
author_rank: Super Contributor
timestamp: February 18, 2023, 04:55:02 am
content: Quote from: Psi on February 17, 2023, 03:45:21 amReally? I use a 0.7zoom with 10x eyepieces for soldering down to 0402 all the time. More zoom for smaller parts.I have a 0.5 Barlow but almost never put it on unless I need the aforementioned working distance bump. Then it's right back up to the same approximate magnification.

author: Psi
author_rank: Super Contributor
timestamp: February 18, 2023, 09:04:54 pm
content: Quote from: Smokey on February 18, 2023, 04:55:02 amDo you have a tiny soldering pencil, like a JVC.I find without the barlow trying to get the iron into a good position can be super annoying.But i'm normally soldering 0805 and 0603 so maybe it's just that.

author: KaneTW
author_rank: Frequent Contributor
timestamp: February 18, 2023, 10:30:51 pm
content: Quote from: thm_w on February 17, 2023, 11:10:33 pmDepends on the ocular. Field numbers increase with decreasing magnification, so in any case you see more image. You can also change the objective to have reduced magnification.

author: ygi
author_rank: Regular Contributor
timestamp: February 18, 2023, 11:13:12 pm
content: I believe he's talking about how lower magnification eyepieces feel like looking through a keyhole. You don't have much wiggle room when it comes to where you must position you head to see anything.On the other hand, so-called Wide Field eyepieces allow for larger angle of vision but I think they don't make WF eyepieces below x10 magnification. Or maybe high end brands make them, IDK.

author: Smokey
author_rank: Super Contributor
timestamp: February 19, 2023, 09:10:03 pm
content: Quote from: Psi on February 18, 2023, 09:04:54 pmYa, Metcal MX500. I hear you on hunting for where the tip of the iron is sometimes when it's out of the field of view. Sucks worrying about stabbing yourself with the hot iron tip when you lose track of it.