USB+HDMI/DisplayPort microscope with optics that will be 1 meter above my table

[2vlado]

Hi all, I'm Vladimir.

I'm new here. I'm looking for a microscope for soldering/inspection with USB+HDMI/DisplayPort output with optics that can be 1 meter above my table. Basically I want it to be above the upper edge of my display. At that distance it'll be more of a telescope than a microscope. I need optics with adjustable magnification and focus. I want it to be attached via an arm to a shelf that is mounted to a wall behind my monitor. My budget is around 500$/€, no hard cap on the price. My current display has 2560x1600 resolution and I plan to upgrade to a 4K display in near future. So preferably the camera should have 4K resolution. Since I don't know anything about microscopes and optics I'm looking for an advice.

Thanks a lot in advance!

[Phil1977]

Hi Vladimir,

unfortunately optics are not really on your side with this setup. Especially the "depth of field" more or less kills this idea, because it gets shallower with a largel focal length. As you mentioned you need something like a telescope for this idea, and telescopes have the longest focal lengths with the shallowes depth of field.

For workshop use you need a usable depth of field. You need at least a microscope that can image e.g. a solder blop completely without "focus-stacking" through all the layers.

Another issue is mechanical stability. The angular resolution of such a telescope would be so good that you need an absolutely rock solid fixture. You say price is negotiable, but these things can get very expensive!

Another issue is "seeing". In the open scenery, telescope images suffer from small temperature fluctuations of the air. I´m not sure, but I assume if you use a hot-air-gun below a telescope camera you will never get a sharp image.

All these issues more or less vanish if you place the lens near to the object - so is it really worth to such a clean desk?

[2vlado]

Hi Phil.

Thank you very much for your response. The problem is that my desk is primarily for computer work and I use it only occasionally for electronics. So I need to prioritize ergonomics for computer work. Regarding your concerns of stability, the arm will be attached to a shelf behind mi monitor, so even if kick the desk it will not move. So I'm not too concerned about stability. Regarding the fluctuations of the air, so far I don't even have a hot-air-gun and I don't think I will buy one in near future.

So far I found these lenses. Not sure if they are good or bad.
https://www.aliexpress.com/item/4000053323535.html

Thanks a lot!

[Phil1977]

I do not know these lenses in detail, but it seems they have only one "adjustment ring" for the magnification factor. So I read the specification as e.g. a work distance of 210-1000mm with magnification ratios between 0.7x-5x, depending of the set distance.

In other words, if you fix the lens over your table, you *probably* only have one magnification available. Usually a large working distance means low magnification, so in case of the upper lens, you could only work with the 0.7x magnification.

Though the magnification is little, you will have a very shallow depth of field. From my experience this will not be a usable microscope.

Anyhow, the chinese lenses are really cheap and often not to bad. If you´re not to hurt by their price, I´d order one and try. The issues with depth of field will be even worse with more expensive lenses that usually have a larger opening - so if you find out the depth of field is not usable, you know it won't get any better by spending more money.

(And just for completeness: Yes, more expensive lenses may have a variable aperture that can help with the depth of field issue. But as it is always with optics and life in general: It consists of compromises - if you close the aperture so far that you get an acceptable depth of field over the distance, you loose so much light that a usual lab illumination is far to dark. If you close the aperture even further, you get into the diffraction limit and loose not only brightness but also sharpness.)

I would try to find a flexible solution where you can stow away the camera if not used, but are flexible enough to bring it into the optimal working distance if needed...

PS: If you need more experience, ask any macro photographer. The bee that you can easily image with your smartphone - because you are near the object and have a wide depth of field (DOF) - will be much harder to catch with a tele-macro-lens that allows a large working distance. And photographers can spend a lot of time just adjusting the lens, while a microscope should be always and easily available...

[thm_w]

If you get an autofocus microscope that might help a bit with the working distance. 1080P: https://www.aliexpress.com/item/1005004675631480.html 4K is quite a bit more.

But as mentioned, just get a microphone boom arm and then you can easily stow the microscope out of the way when its not needed.