MicrobeHunter.com Microscopy Forum

With some microscopes, the maximum optical tube diameter is very close to the standard eyepiece f.o.v. Increasing the apparent f.o.v. of the eyepiece results in no or a minimal increase in the real f.o.v. because the eyepiece field stop is not the arbiter of the field diameter; the optical tube is.

I did receive them, they work ok but the olympus WHK10/20 are way taller, I would need to get them out of the tube around 10mm to be parfocal.

Only one of the BH2 eyepieces can be extended, planning to remove one from a binocular head so both eyepieces on the trinocular head can be extended.
First I will disassemble the binocular to asses if it is possible and how challenging this mod would be.

Other solution would be just using made to measure spacers (I went for that, now both camera and eyepieces are parfocal to each other)

apochronaut wrote: ↑

Fri Mar 19, 2021 2:22 am

With some microscopes, the maximum optical tube diameter is very close to the standard eyepiece f.o.v. Increasing the apparent f.o.v. of the eyepiece results in no or a minimal increase in the real f.o.v. because the eyepiece field stop is not the arbiter of the field diameter; the optical tube is.

In this case the edge of field would not appear in sharp focus with either eyepiece, correct?

hans wrote: ↑

Fri Mar 19, 2021 1:26 am

The inner diameter of the the tube on mine is exactly 22 mm, so if you are not seeing a 2 mm increase in field number maybe the intermediate image is at a different depth from the top of the eye tube relative to the original eyepieces? Is parfocality when switching objectives worse with the 10X/22 vs. the original eyepieces?

Nope, parfocality on the objective end is identical. The measurements check out, 20mm for the 10x/20 and 22mm for the 10x/22. The main differences are that the 10x/22 is a considerably shorter eyepiece and also has larger diameter glass. I am happy with it, so I am not concerned.

hans wrote: ↑

Sat Mar 20, 2021 12:20 am

apochronaut wrote: ↑

Fri Mar 19, 2021 2:22 am

With some microscopes, the maximum optical tube diameter is very close to the standard eyepiece f.o.v. Increasing the apparent f.o.v. of the eyepiece results in no or a minimal increase in the real f.o.v. because the eyepiece field stop is not the arbiter of the field diameter; the optical tube is.

In this case the edge of field would not appear in sharp focus with either eyepiece, correct?

I think that is what apo would be suggesting, but that is not the case in real life. These things are unusual. If you put your eye uncomfortably close to each of them then on the binoc head they are both sharp, both with same field of view. An actual comfortable spot to use them is with your head back a bit and the field of view on each is the same as each other, but a bit smaller. Still like a bloody IMAX screen though, huge!

On the monocular head the 22 has a slightly larger field and the very edge is the tube not the eyepiece, but again, thats an uncomfortable spot to keep your eye. Move back a little and its sharp, a bit smaller, and more comfortable. I dont know why or how, but thats what I see.

Also strange, but fine, only one eyepiece adjusts on the binoc, and it matters whether the 20 or the 22 is on that side. Cant adjust them parfocal one way and its perfect the other way.

Are these $50 10x/22 eyepieces available on Ebay or only from Aliexpress? I haven't been able to get Aliexpress to work on my computer--tried two different browsers and turned off various security features but the site still hangs. I'm wondering if these eyepieces would work on my Laborlux...

I've only ever bought them on eBay. Hey would lack the needed compensations for Leitz objectives which will likely be immediately noticeable, but might be fun to try anyway.

That's what I feared. But not a huge risk, I guess, given the price, and I've sometimes been pleasantly surprised by cheap optics. Is this the Ebay listing? No eyecups shown but otherwise seems to match the description.

https://www.ebay.com/itm/273482756677?h ... SwtAtbrIOC

That should be the one, yeah.

I would assume that this aliexpress listing is the item in question. If you search for "wf10x/22mm," you will see lots of possibilities. Looks like it comes in a few colors, too. I might need to hot rod out my scope with a red one.

There are lots of (non adjustable) 30mm mounting diameter products that come up in that search, so double check. It appears that you can get the diopter-adjustable one in both sizes and a couple of colors without too much trouble.

These are very interesting eyepieces from a few standpoints. First they are a one size fits all kind of design. The actual eyepiece is locked into the fat squat section above the eyepiece tube. From there, the f.o.v. or application can be modified. The glass diameters are wide enough to support a very wide f.o.v. and as Scaro. quickly demised, the body will accept 30mm tubes to be converted into a u.w.f. eyepiece.
In their native form, they utilize a very small widening in the i.d. of the 23.2mm tube as a field stop. I don't know if they are actually 22mm. They are slightly bigger than 20mm anyway. I haven't measured them. They are a focusing eyepiece. Threading the eyelens out to the maximum height, increases the f.o.v. because there is no field stop, just the inside of the upper(narrower) part of the barrel, so whatever part of the barrel it focuses on becomes the field stop. One could possibly get a slightly greater than 22mm f.o.v. out of them by grinding off some of the thread that attaches the mounting tube. This would allow the eyepiece to focus past the edge of the tube internal cutaway, into the wider part, therefore a wider field stop. They appear to be basically a neutral design, possibly slightly positive.

I have to look at these as remarkable, especially in light of their ridiculously low cost. Really a triumph and only really possible from a planned economy. I would imagine that they are made in the upper tens of thousands and the basic design is used in most of the mid to upper grade Chinese scopes.

"WF10X 22MM Adjustable High Eyepoint Wide Angle Biological Microscope Eyepiece Lens 23.2mm with Rubber Eye Guards Caps"

I finally received mine. I did in the end get Aliexpress to work so these were ordered from China.
https://www.aliexpress.com/item/3289113 ... 4813TR3giT
I see they now want $66 for a pair. I paid $41 but that included a discount they gave me after I got sidetracked and forgot about completing the order for some time. I believe the original price was right around $50. Once I actually completed the order, the eyepieces took about 2 weeks to arrive.

The eyepieces work quite well in my Olympus IMT-2, the only microscope I've tried them on as yet. Nice and bright. Slightly larger FOV than the Olympus WHK 10x/20L-H eyepieces. No spherical aberration that I can see, flat out to the edge. However on vertical lines, from about halfway out from center there is just a hint of faint blue fringe on the line's inner edge, so a bit of CA. If I can find my cell phone adapter, I may take a photo to see if my eyes have missed anything. Overall, I prefer the Olympus eyepieces but I may use these for awhile to see if my opinion changes.

Those eyepieces themselves are quite neutral in their correcting capacity ; neither correcting or compensating. They work best where neither of those are required by the time the image gets to the eyepieces. They most likely evolved out of the Nikon knockoff NIS45 and NIS60 infinity programs. The IMT-2 as a 160mm Olympus system probably still needed some ca correction built into the eyepieces, so your Chinese eyepieces are undercorrecting in the system. You should also see a slight band of yellow on the outside.

Yeah, Olympus bh2 era objectives are on the low end of correcting (at least for chroma) but it's still needed. I have seen setups with the b&l 15x ultra wf eyepieces on olympus stands--not sure how well the compensations match but it may be a better option for imax-like viewing.

Would you entertain trades for a pair of those eyepieces? A bit of cabinetry, a chest for slides, dissecting table, custom armrests, cases of particular dimension etc I am a competent joiner and have long been covetous of those fine 15x