Kyowa Lumiscope No. 612360

[dtsh]

I had seen a listing for what looked like a decent but older monocular JIS scope; it came with 10x and 5x eyepieces, a Clay-Adams Scopelite substage lamp, hard case, and a few other bits and pieces, but there's a limit to how many microscopes I can reasonably justify having and I have been above that limit for some time now so my active microscope purchases have been on hold while I slim down the duplicates in my collection. Still, I put in a very low bid on it knowing it would sell for more, but it would make tracking it a lot easier. Unexpectedly, my bottom of the barrel bid was the only bid submitted and I found my collection had grown by another scope. I figured that I could repurose the hardcase and some of the other bits if neccessary so that it wouldn't be a total loss, but what I found was a decent instrument with a few warts here and there.

First off, a quick look-see after it was cleaned up. It's in pterry good shape and appears to be from somewhere around 1961, give or take. If anyone knows of an accurate dating using the serial numbers or such, I would appreciate the information.

lumiscope_1.jpg (118.27 KiB) Viewed 2022 times

The fine focus knob has a slighteccentricity in it's rotation, perhaps the knob got a hard bump at some point. It doesn't affect the use and is only noticeable when looking at the know while rotating it, I may try to correct it later.

lumiscope_2.jpg (91.08 KiB) Viewed 2022 times

Mechanical stage

lumiscope_3.jpg (125.22 KiB) Viewed 2022 times

And substage with condenser and mirror.

lumiscope_4.jpg (96.91 KiB) Viewed 2022 times

Initial views as I was cleaning it suggested that the original eyepieces were probably the biggest compromise, they deliver decent, but very narrow views compared to other eyepieces I tried with it, I'll post some examples shortly, but rough calculations suggest a FN of somewhere around 13.5, which is quite narrow.

[dtsh]

The view from the eyepiece delivers a flatter field of view than these images suggest, likely due to my camera mount not being well aligned. I was more interested in just getting the measurements than I was in getting good, clear images of a calibration slide (sans coverslip). Images intended to represent the view will come later. In each of the examples I tried to align the "0" position with the edge of the field of view. Using a rough measure of FN(Field Number) where the viewable diameter * objective power = FN for each eyepiece gave reasonable results on the eyepieces for which I knew the FN. The two AO examples were included as references.

First is with the original Lumiscope 10x eyepiece. The field of view with this is the narrowest of any eyepieces I have by a noticeable margin. The measured diameter is 1.4mm so we get a measley 14mm FN; eye relief is also pretty poor

EP_Lumiscope_10x_14mm.jpg (47.83 KiB) Viewed 2006 times

Next up is what was previously my narrowest eyepiece an American Optical Cat.138 10x, which when compared to the Lumiscope's 10x, seems a wonderful improvement at 1.7mm measured diameter giving it a FN of 17mm.

EP_AO_138_17mm.jpg (54.49 KiB) Viewed 2006 times

I happened to have a pair of no-name Chinese 10x-18mm eyepieces; this one deviates from the expected measurement slightly coming in at around 1.75mm or so, but it's close enough to the claimed 18mm and still far above the 14mm of the Kyowa.

EP_Chinese_10x-18mm.jpg (52.15 KiB) Viewed 2006 times

Lastly is an American Optical Cat.146 10x, a commonly used eyepiece found on a variety of AO 160mm scopes and also used with the AO Cycloptic, among others. It's reported to have a FN of 19mm, which is what I came up with as well.

EP_AO_146_19mm.jpg (51.55 KiB) Viewed 2006 times

[apochronaut]

Those are very solid microscopes. Classic in style with simple huygens eyepieces. I have seen the same model as a genuine Kyowa binocular , a Bristolscope. a Lafayette and with some very slight variation, a Tasco. The Tasco had a 20X eyepiece in the kit promising an optimistic 2000X.
That same monocular model is featured on the very common Tasco yellow and black cardboard boxes from the mid.-60's. There are 4 photo panels, 3 of which are of a Caucasian guy wearing a white lab coat working at that scope. Bottom right panel is an Asian. He's got his eye glued to that eyepiece, doing very serious work, implying that the owner of that shiny black hobby scope IN the box was also capable of such revelations. Usually, they were.

[dtsh]

Those are very solid microscopes. Classic in style with simple huygens eyepieces. I have seen the same model as a genuine Kyowa binocular , a Bristolscope. a Lafayette and with some very slight variation, a Tasco. The Tasco had a 20X eyepiece in the kit promising an optimistic 2000X.
That same monocular model is featured on the very common Tasco yellow and black cardboard boxes from the mid.-60's. There are 4 photo panels, 3 of which are of a Caucasian guy wearing a white lab coat working at that scope. Bottom right panel is an Asian. He's got his eye glued to that eyepiece, doing very serious work, implying that the owner of that shiny black hobby scope IN the box was also capable of such revelations. Usually, they were.

I admit my expectations weren't very high, but I've been fairly impressed at what I've seen, all things considered. There's a bit too much play in the dovetail between the stand and the fine focus and the 4x obejctive performs very poorly, but the field of view for the other objectives is fairly flat, moreso than any of the AO 160mm objectives I have, which I certainly did not expect. I think I should be able to fix the play in the dovetail, but I don't think there's much I can do about the 4x. We will see what other surprises I can find.

[dtsh]

My initial opionion of the 4x objective continues to get lower and lower, but my opinion of the others remains relatively high. For the prices these frequently sell for (sub $50) it's a pretty decent instrument and patience can often pay off allowing the acquisition of one with some nice accessories at even lower prices.

First off I put my calibration slide on the stage, added a drop of water and placed a coverslip on it. I feel the calibration slide provides a nice test of planarity and it's lack of detail or color make chromatic aberation easy to see.

With the 4x objective, I tried and tried to get it to deliver the subject in focus and this was the best image I could get.

cal_4x.jpg (48.24 KiB) Viewed 1965 times

The 10x delivered a nice flat image.

cal_10x.jpg (79.84 KiB) Viewed 1965 times

The 40x also performed well and I was impressed with the flat field.

cal_40x.jpg (87.87 KiB) Viewed 1965 times

Even the 100x oil objective performed well, but later tests suggest it might have a very limited working distance.

cal_100x.jpg (57.54 KiB) Viewed 1965 times

[dtsh]

Next up was a slide of some mosquito wings I've imaged many times.

As expected, the 4x delivers a poorly focused image and really isn't useful for much beyond just scanning the slide, but as will be seen later, it's of limited use even there.

Moz_4x.jpg (82.9 KiB) Viewed 1965 times

10x

Moz_10x.jpg (151.48 KiB) Viewed 1965 times

40x

Moz_40x.jpg (82.62 KiB) Viewed 1965 times

100x

Moz_100x.jpg (68.75 KiB) Viewed 1965 times

[dtsh]

Another sample that's been imaged many times and one that many will appreciate for it's utility, some samples from a diatom test slide.

Here the 4x was abysmal, due to the size of the diatoms and the objective's poor performance it was incredibly difficult to locate them on the slide.

Diatoms_4x.jpg (45.14 KiB) Viewed 1964 times

10x

Diatoms_10x.jpg (50.83 KiB) Viewed 1964 times

40x

Diatoms_40x_1.jpg (62.99 KiB) Viewed 1964 times

Diatoms_40x_2.jpg (69.02 KiB) Viewed 1964 times

I couldn't focus on the diatoms with the 100x and I was a tad worried about damaging my most expensive slide, so there aren't any 100x images of the diatoms.

[dtsh]

This last set I intended to image just the 4x as an example of how well I thought it performed and chose my most "lousy" slide....a female human louse, but decided to image the 10x and 40x as well, the subject is just too deep in the media to image with the 100x, a failing many other 100x objectives share so it's not really a criticism of the 100x in this case.

A very lousy 4x image.

Lousy_4x.jpg (73.02 KiB) Viewed 1963 times

10x

Lousy_10x.jpg (75.1 KiB) Viewed 1963 times

40x

Lousy_40x.jpg (83.22 KiB) Viewed 1963 times

All in all, I think the scope is decent, but certainly not great. If I can manage to find the issue with and repair the 4x it would be better. It is greatly improved with a better eyepiece, but I imaged it with the original 10x to provide a good comparison.

[apochronaut]

Are you factoring in the fact that AO objectives of that era could be imaged via the # 142 and later the # 177 huygens eyepieces, student widefields such as #138 or the # 146 w.f (20mm f.o.v.). . Since those Kyowa horseshoe microscopes had a base design that utilized simple huygens eyepieces managing about 14mm , then the AO objective planarity seems about the same to me.

I use a broad range of AO achromats plus higher N.A. achromat research objectives and a bunch of phase versions of the above. The planarity is about the same for a 1950's design.
Don't forget that the Kyowa is solidly 1960's, even mid- 1960's and by then AO had infinity corrected 19mm f.o.v. planapos in prototype at least. I think they were issued for commercial sale in late '66.

[dtsh]

Are you factoring in the fact that AO objectives of that era could be imaged via the # 142 and later the # 177 huygens eyepieces, student widefields such as #138 or the # 146 w.f (20mm f.o.v.). . Since those Kyowa horseshoe microscopes had a base design that utilized simple huygens eyepieces managing about 14mm , then the AO objective planarity seems about the same to me.

I use a broad range of AO achromats plus higher N.A. achromat research objectives and a bunch of phase versions of the above. The planarity is about the same for a 1950's design.
Don't forget that the Kyowa is solidly 1960's, even mid- 1960's and by then AO had infinity corrected 19mm f.o.v. planapos in prototype at least. I think they were issued for commercial sale in late '66.

My exposure to AO's 160 line is admittedly, limited. My primary comparison is with the AO Series 35 that I have (viewtopic.php?t=14896).
You make a fair point that, apples to apples at 14mm FN, they are certainly comparable. In my mind I was remembering the AO's field and planarity with the 10x Cat.146 but not accounting for the significantly greater fov. Perhaps later I'll put them side by side and compare a variety of the eyepieces I have between the two. Thank you for pointing that out, it should have been obvious, but I overlooked it.