It's kind of "old school", but I prefer the Bausch & Lomb (Leica) "Stereo Zoom" series of microscopes with a ring light. I have used several variants, but my preferred choice is the 0.7X to 3.0X head with 10X eyepieces, mounted on the boom base. It will typically have about a 2.5" working distance depending on the exact magnification used. (Lower magnification = greater working distance.)

I have one of the cheap stereo inspection microscopes for personal use but also have been using them for decades at work. There is a clear difference/benefit of the quality microscopes from the likes of Leica. This is not limited to overall quality but importantly to depth of field. So the optical clarity is much better in every respect. Some day... I hope to be able to upgrade to a Leica but the cheap ones get the job done.

 

Agreed about the misuse of the zoom/focus. Usually, only one eyepiece (ocular lens?) is adjustable; the other is fixed focus. When I first sit down to a new microscope, I gently close my eye on the adjustable eyepiece and adjust the main focus at maximum zoom. I then gently close the other eye and adjust the adjustable eyepiece for the best focus. I check overall focus and repeat if necessary. I emphasized gently closing the eye because if you close your eye under muscle strain, you are likely to change the shape of your eyeball slightly for a short period of time after opening your eye again, thus changing the normal focal point of your eye for a bit.

This might be what you are saying but I'm not sure. I think the most efficient method is to...

• Zoom in to the max, focus the microscope using the height adjustment.
• Zoom out to the min, focus each eye piece.

Now it should remain in focus through the entire zoom range.

 

General comments about stereo microscopes and in particular accessories...

Number one priority is lighting. It's easy to have too little and difficult to have too much.

If you have properly selected a microscope then you will be aware of the tradeoff between magnification and working distance. A set of barlow lenses will let you experiment with this. Sometimes I just need more working distance and other times more magnification. So while I don't change my setup often, I do sometimes do so by adding removing barlow lenses.

I've played around with different eye pieces... but not with any significant benefit.

 

I also have a bunch of power plug adapters or I can rewire one in the two buckets full of wall warts... I am such a packrat! I already downloaded the manual and the software. Arghh 7W spec and all mine are 1A. Ordered 2A. Thanks for the heads-us Dennis!

Did you figure out that the plug is 1.7mmX4mm, not 1.3mmX3.5mm? And that the software requires admin privileges to run?

I referenced this thread when I was ordering some plugs and ordered the wrong size...

 

Did you figure out that the plug is 1.7mmX4mm, not 1.3mmX3.5mm? And that the software requires admin privileges to run?

I referenced this thread when I was ordering some plugs and ordered the wrong size...

Yep, had a bit of trouble turning it on at first until I figured out the software but now working fine. OTOH I've been getting a lot of other "Junk" from eBay and having to ship it back. Par for the course. Some of the other items I've been looking for are "no return" and only commented as used. So no basis for return if they don't work or are even not repairable at significant cost i.e. parts only items.