"disecting" microscope questions...AO Spencer 23LF

[Jay]

Hello,

I hope I'm in the right place for this question.

I'm trying to set up an AO spencer stereo microscope, model 23LF to use for engraving. I bought a great scope. Seen here

https://www.ebay.com/itm/American-Optic ... 2749.l2649

I mostly was attracted to the boom stand, with micro adjuster. The stand is necessary to position the scope over the engraving vise.

The scope is outfitted with WF10x eyepieces, and 1x, 2x. and 3x oculars, but 10x is too powerful. What I need is about a 5x, to get a wider field of view. So, I have another old microscope, more of a lab scope I guess, by Zeiss from the '60s. In the kit, it has an 8x eyepiece, but that has much less field of view than the 10x. So I know I need a WF eyepiece, with a 23mm tube, and I'm looking at eyepieces on ebay. Bunch of new Chinese unbranded. Amscope has a WF5x, but Amazon reviews don't seem good. A few on ebay by known companies, like Zeiss, Olympus, Bausch. But I can't tell if they're wide field, or what. Any suggestions out there? About all I can do at this point is start buying them and sending back until I find some that work, or shop for a different microscope head to go on my stand.

Thanks!
Jay

[75RR]

Have you considered a large magnifying glass instead? Would be easier to position as well. What is the total magnification needed?

Here is an 8x magnifying glass with led lights: https://www.ebay.com/itm/Clip-on-Big-Il ... Desc=0%7C0

[PeteM]

It's a nice stand, but a fairly old style (for A-O) microscope. They moved from that Greenough design to "Cycloptic" and other styles.

I'd suggest replacing it with something like an Olympus SZ (Stereo Zoom from 7x to 40x), a Nikon StereoZoom, a Bausch & Lomb stereozoom, or a 50's-70's era American Optical "Cycloptic". Each of these microscopes came with wider field eyepieces (22 fn on the Olympus, for example) AND has a screw thread at the bottom that can take accessory lenses to increase or decrease the magnification.

Best of the bunch -- all available and somewhat affordable used -- might be an Olympus SZ with a .3x auxiliary lens. This would have a wide field and zoom from about 2x to 12x. You might expect to pay $100 or so for the supplemental (.3x) lens and maybe $200 for the SZ scope. You'd also get extra working distance (something lacking in many cheap stereo microscopes) that might be useful in engraving. Be sure to add good LED lighting - a couple gooseneck LED lamps off Ebay might set you back another $30.

You could sell the existing scope or give it to a curious kid in your family? Shouldn't be hard to repurpose the stand you bought for your new scope -- and also to make a table stand for the old AO one.

[apochronaut]

Hello,

I hope I'm in the right place for this question.

I'm trying to set up an AO spencer stereo microscope, model 23LF to use for engraving. I bought a great scope. Seen here

https://www.ebay.com/itm/American-Optic ... 2749.l2649

I mostly was attracted to the boom stand, with micro adjuster. The stand is necessary to position the scope over the engraving vise.

The scope is outfitted with WF10x eyepieces, and 1x, 2x. and 3x oculars, but 10x is too powerful. What I need is about a 5x, to get a wider field of view. So, I have another old microscope, more of a lab scope I guess, by Zeiss from the '60s. In the kit, it has an 8x eyepiece, but that has much less field of view than the 10x. So I know I need a WF eyepiece, with a 23mm tube, and I'm looking at eyepieces on ebay. Bunch of new Chinese unbranded. Amscope has a WF5x, but Amazon reviews don't seem good. A few on ebay by known companies, like Zeiss, Olympus, Bausch. But I can't tell if they're wide field, or what. Any suggestions out there? About all I can do at this point is start buying them and sending back until I find some that work, or shop for a different microscope head to go on my stand.

Thanks!
Jay

I will test some eyepieces in a similar stand.

[apochronaut]

Hello,

I hope I'm in the right place for this question.

I'm trying to set up an AO spencer stereo microscope, model 23LF to use for engraving. I bought a great scope. Seen here

https://www.ebay.com/itm/American-Optic ... 2749.l2649

I mostly was attracted to the boom stand, with micro adjuster. The stand is necessary to position the scope over the engraving vise.

The scope is outfitted with WF10x eyepieces, and 1x, 2x. and 3x oculars, but 10x is too powerful. What I need is about a 5x, to get a wider field of view. So, I have another old microscope, more of a lab scope I guess, by Zeiss from the '60s. In the kit, it has an 8x eyepiece, but that has much less field of view than the 10x. So I know I need a WF eyepiece, with a 23mm tube, and I'm looking at eyepieces on ebay. Bunch of new Chinese unbranded. Amscope has a WF5x, but Amazon reviews don't seem good. A few on ebay by known companies, like Zeiss, Olympus, Bausch. But I can't tell if they're wide field, or what. Any suggestions out there? About all I can do at this point is start buying them and sending back until I find some that work, or shop for a different microscope head to go on my stand.

Thanks!
Jay

The link you provided does not bring up the described microscope, oddly. It brings up a completed auction for an AO series 4 but it seems to be an ebay fault. However, I do know the 23LF. The problem with reducing the magnification by using low magnification eyepieces, is that there is a limit to how far you can go and maintain the W.F. feature, due to restrictions in the optical pathway. The lowest you can go and get a decent field is 6X but their apparent field is still not as wide as a W.F. 10X, although the real field coverage is greater.
You also have to be careful in matching optics. W.F. optics from other mfg.'s are unlikely to provide good edge to edge correction, although some might, and completely by accident or due to the fact that they were based on copying someone else's design. It is trial and error to determine compatibility.
The eyepieces supplied with that microscope were 10x cat.# 146B, as well as 15x and 20X. Your model came with 1x, 2X and 3X objectives but there also was a .7X available. Earlier versions of that microscope from the 40's and early 50's, had a greater array of eyepieces, with slightly lesser fields of view but not much. The possibilities were 9X, 12x,15x and 18X; all of a fairly W.F. If you use the 9X with .7X objectives , that gives you 6.3X total, so a considerably lower overall magnification, and with a fairly good field. I have a set of the 9X available, if you want them. I will check and see if I have a .7X objective pair. I used to.

While I agree, somewhat with Pete M, you would be into considerable extra cost to switch to another scope and what about the boom stand feature? That isn't going to be an easy replacement accessory. If you switched to a Cycloptic or Stereozoom, on which you could fit low magnification aux. lenses, getting down to about 1/3X with each of those, you could still use the same boom stand.
F.Y.I. : the complete optical lineup for your 23LF scope in addition to the more modern W.F. pairs 146B-10X W.F.,147B-15X W.F. 157B-20X W.F., and the 9X,12X,15X and 18X original eyepieces included .7X,1x,2x,3x,4x,6x, and 8X objectives, in a quick change 3 objective nosepiece.

[75RR]

The link you provided does not bring up the described microscope, oddly. It brings up a completed auction for an AO series 4 but it seems to be an ebay fault.

I took the AO for what you had bought - here is a more direct link.

https://www.ebay.com/itm/-/173387864497 ... 675.l10137

[apochronaut]

I did a couple of quick tests for you. With the 9X eyepieces and a 1.0X objective, the actual field viewed is 20mm. With the 9x eyepieces and the .7X objective the actual field viewed is 27.5mm.
Using the 10X W.F. eyepieces and the 1.0X objective , the actual field viewed is 18mm. With the 10X W.F. eyepieces and the .7X objective, the actual field viewed is 24mm.

There is also a difference in the working distance, with the w.d. provided by the original formula eyepieces being considerably greater than the 10X W.F.

So, the .7X objective and 9X eyepiece pairing gives a greater than 50% increase in the field, than what you have right now, greater w.d. and a slight increase in image quality.


It is important to realize that at one time the series #23-28 series Greenough microscopes were AO's flagship stereo microscopes( W.W. II) but they remained in production into the early 60's. Attention had turned to the Cycloptic program by the 50's and shortly after the Stereozoom program. The #23-28 group became relegated to a more pedestrian purpose( student, utility, shop) and at a more economical price. The W.F. series of eyepieces were designed for the Cycloptic and the series 2/4, and ended up doing double duty in those older Greenough stereos, probably because it was not cost effective to continue to mfg. the older 9-18X series of eyepieces for a microscope that was sure to be discontinued, once the last production ran out. It is my opinion that the older series of eyepieces provide better imaging in those #23-28 series microscopes than the #146-157 W.F. eyepieces.

[apochronaut]

I looked to see, if I had an extra .7X but only a 1X. I messaged you through the system and included my email.

[MicroBob]

Hi Jay,

I have a halfway modern Leica ES2 student stereo microscope here and with the 10x overall magnification I get a FOV of 20mm.

The fields of view of an old Olympus SZ III stereo microscope you can find here:

https://www.google.com/url?sa=t&rct=j&q ... F2r1KMnTp-

With a 0,5x auxillary lens you get 62mm FOV at 159mm distance - probably nice for engraving!


Bob