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PostPosted: Thu Feb 14, 2019 12:14 am 
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Joined: Mon Jan 21, 2019 4:54 pm
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Hi. Does anyone know, other than the continuous zoom capability on the newer AO stereo scopes (e.g., model 580X), how does image quality compare? I have a Cycloptic and am enjoying it. I see many newer AO continuous zoom scopes on ebay and was wondering... I think I know that the Model 40s are less advanced.

Thanks!


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PostPosted: Thu Feb 14, 2019 1:53 am 
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Location: Santa Cruz, CA
I have both versions. As a casual observation, the 580 doesn't seem to have a better quality image than the Cycloptic -- just the zoom feature. And while the zoom is cool, if you actually wanted to measure things with an eyepiece reticle calibrated to a scale, the multiple-fixed-focus could be better. With a zoom you'd be less sure exactly where you are.

Somewhat more modern stereo microscopes from good makers will have a wider field of view than either the 580 or the Cycloptic and perhaps a bit more contrast.

The Cycloptic is quite good despite its age. It claimed an apo objective lens and used silvered prisms rather than front surface mirrors to get the images into the eyepieces. Those can be cleaned in an old scope, while the mirrors used in some B&L and other scopes are a bit more finicky. The one problem common to Cycloptics is detachment of the prisms if they're bumped or dropped. They can be glued back in place with a bit of attention to detail if they haven't been overly damaged.

Apochronaut, if he posts, might have a more definitive reply.


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PostPosted: Thu Feb 14, 2019 3:40 am 
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The 3 and 4.2X AO zoom scopes are a little optically simpler than the model 580 6X , which in some AO literature is described as " high resolution". I would have to say, I agree with that but the resolution difference is not huge.
The Cycloptic has yet an edge in resolution over the 580, largely due I think to it having a slightly better colour corrected image plus not having the complications of the zoom optics. The Apochromatic primary objective of the Cycloptic is fairly unique
and is something one would only expect to find on much more expensive and celebrated microscopes.
The advantage in resolution that the Cycloptic has is to some degree outweighed by as Pete noted, slightly poorer contrast and the more you burden it with aux. optics to increase the magnification the contrast dips further; less so with the 580 once over 25X, the Cycloptics limit with the standard 10X eyepiece.

The Cycloptic has a fantastic array of fractional apochromat objectives though, 3/4,2/3,1/2,1/3 and 1/5X. Some of these are very hard to find but they are out there, so for special purposes, especially on a boom it speaks to the instrument's remarkable versatility. It is light, small and has a much smaller footprint than the 580, so if you wanted to outfit yourself with a very fine stereo microscope with multiple high quality accessories cheaply; the Cycloptic is the way to go.
If you want the convenience of zoom, with easily obtainable magnification up to 60X; the 580 won't disappoint, especially at the prices they can be had for. They sit tall on a bench and are a little big and heavy on a boom but so is any other zoom stereo of it's capability. Lots of accessories for it too.

One needn't be hampered by a 23mm tube and a 20mm f.o.v. either, so a word about field of view and magnification. For quite a while now, I have been using the Bausch & Lomb U.W.F. 15X eyepieces in a Cycloptic. These were made for viewing military reconnaisance photos through a B & L 240 stereozoom over a light table. They are outstanding eyepieces and turn the Cycloptic into a true widefield stereo, very close to the standards one would get with modern scopes costing many many thousands of dollars. The real field through the B & L 15X U.H.F. eyepieces is within a fraction of that captured by the 10X 20MM f.o.v. eyepieces common to many microscopes, so the apparent field of view is out around the edges of your shoulders. The field is stunning and remarkably flat and distortion free. They also work just as well on the 580 but bear in mind that taking any stereo zoom to 90X will reduce contrast quite a bit. On the Cycloptic the limit is 40X with the standard 1X main objective and 15X eyepieces and I have not tried those eyepieces with a 2X aux. lens.


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PostPosted: Thu Feb 14, 2019 10:31 am 
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Joined: Mon Jan 21, 2019 4:54 pm
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Wow, thanks to you both for the great info!

It makes appreciate my low cost and flexible Cycloptic system even more. I already purchased the 2/3 and 2X aux lenses and AO 15X WF (#147) eyepieces. So far I prefer the standard 10X eyepieces, perhaps because of the wider FOV?

I looked and didn't find any B & L U.W.F. 15X eyepieces on ebay (lots of 15X W.F.'s). Sounds like they might be rare. Please confirm that they would be a nice step up from the AO # 147s and if you have any suggestions on where to buy them.

Thanks again for sharing your knowledge!!


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PostPosted: Thu Feb 14, 2019 1:10 pm 
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Joined: Fri May 15, 2015 12:15 am
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The B & L U.W.F 15X are not really rare but they are uncommon. They are very large with a 25mm eyelens and perform much better than the # 147. There is nothing really wrong with the 147's, supplied as original equipment but everything has a cost. There is only so much they could engineer into them and keep the cost in line. The B & L eyepieces had no cost limit. They were used for spying on the Russians and the Cubans and everyone else in the world probably. Their original price was about 3 times what the entire Cycloptic cost.

They were also used industrially and sold under the make, FJW and later the brand Reichert was put on them. They may also have been branded Cambridge but they were made by B & L.

Sometimes they sell for a very high price because the seller knows their value but sometimes they show up at a good price. I've seen them sell for as low as 50.00/pr.


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PostPosted: Thu Feb 14, 2019 1:24 pm 
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Thanks again apochronaut! I'll keep my eye out!


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PostPosted: Sun Feb 17, 2019 12:38 pm 
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I sought out a pair of the UWF 15x eyepieces on apochronaut's suggestion as well. I ultimately found a seller on Ebay that was selling single eyepieces paired with a B&L Pod for $55/each. I bought two and let him keep the pods. It was definitely a good upgrade.


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PostPosted: Sun Feb 17, 2019 4:30 pm 
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Joined: Tue Feb 24, 2015 1:03 am
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American Optical introduced the Cycloptic in 1957. It was the first American made CMO (Common Main Objective) stereo scope. I say “American” because CMO’s were pioneered by Zeiss. Another way of describing this technology is to use the term parallel light path. It had perhaps the largest fixed working distance of 4 inches. It also utilized one piece glass erect prisms.
The Cycloptic utilizes what is often referred to as a Galilean drum trade marked as the “magna-changer”. A Galilean drum utilizes lenses embedded in a cylinder such that when rotated you can change the magnification of the specimen. Three magna-changer models were available, “J”, “K”, and “M”. Magna-changers J and K offered 8 achromatically corrected elements offering 3 magnifications for each eyepiece objective combination. Magna-changer “M” contained 16 achromatically corrected lenses offering 5 different magnifications for each eyepiece objective combination. Generally speaking stereo scopes utilizing a Galilean drum have the potential for better resolution due to fewer optical components. The more lenses you introduce within the lights path the increased chance for optical aberrations.


I have a Cycloptic that was used by a bank to examine bills etc. For all practical purposes it is new. The optics are quite incredible. It will only go to 25X with 10x eyepieces but if you add a 2X objective it is almost as good as its successors up to 50X, giving up some depth of focus. What it lacks in resolution it makes up for in color/contrast and overall brightness of the image.


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PostPosted: Sun Feb 24, 2019 11:29 pm 
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Joined: Mon Jan 21, 2019 4:54 pm
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I was able to purchase a set of the 15X Ultra WF eyepieces suggested by apochronaut on eBay. I'm super impressed with the image clarity, brightness and field of view. So cool to own optics that are part of our cold war history! Thanks again.


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PostPosted: Mon Feb 25, 2019 7:36 am 
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Posts: 159
The 15x uwf eyepieces are good on everything and give a field of view which i think is slightly wider than my labophot UW head with 30mm eyepieces, which is pretty amazing. That said I think it would be fair to call them rare.
I personally would take a 580 over a cycloptic, since that wide zoom range and higher max mag is really nice for looking at gem inclusions such. But it is hard not to love the cycloptic (still looking for a good stand for mine).


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PostPosted: Tue Feb 26, 2019 12:39 am 
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I prefer the 580 as well, for the ease of using the zoom and the higher magnification, without adding an aux objective. But, as you said, the Cycloptics is still a beautiful scope and the prices on Ebay are quite reasonable.


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