I am a watchmaker with cataracts (soon to be fixed) and I bought a Nikon SMZ thinking the 30mm tubes would provide greater light gathering than my 23mm tube AO 570.
I was losing edges when using a 10X loupe or even the AO for turning. While I know this will be fixed, I might as well have the best image or at least not spend the money on 30mm eyepieces that are no better than good 23 mm eyepieces.
When I looked at the Nikon 15X eyepieces that came with the SMZ, they were field stopped to 23mm. Is this true of all 30mm eyepieces? If so, I might as well just make a bushing for the SMZ tubes and use 23mm eyepieces.
I know from astronomy larger eyepieces yield much better contrast than smaller ones.
Thanks and regards,
Dewey
Any advantage to larger ocular tube size?
Re: Any advantage to larger ocular tube size?
Welcome to the forum, Dewey.
Light gathering ability in microscope is measured / specified by numeric aperture / NA (similar to F number in photography) of objectives. Physical diameter of eyepiece/tube does not indicate such.
I don't know your scopes. But some of my 23 mm 10x eyepieces have field number of 18 mm. For 23 mm 10x eyepieces, 16-20 mm field number is common.
Light gathering ability in microscope is measured / specified by numeric aperture / NA (similar to F number in photography) of objectives. Physical diameter of eyepiece/tube does not indicate such.
I don't know your scopes. But some of my 23 mm 10x eyepieces have field number of 18 mm. For 23 mm 10x eyepieces, 16-20 mm field number is common.
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watchmaker
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Re: Any advantage to larger ocular tube size?
I appreciate your reply; but I thought NA is more related to field of view. Like a camera lens aperture (f stop), the tube size and or field stops determine who much light hits the lens. This results in a brighter image with more contrast.
But, if 30mm tube size oculars are nothing more than a 23 mm eyepiece in a larger mount, then there is no point in spending money on 30mm mount eyepieces.
Both the AO 570 and the Nikon SMZ-1B are high resolution stereo scopes used in inspection and assembly operations with a max. usable magnification of around 50X but with very good long working distance.
But, if 30mm tube size oculars are nothing more than a 23 mm eyepiece in a larger mount, then there is no point in spending money on 30mm mount eyepieces.
Both the AO 570 and the Nikon SMZ-1B are high resolution stereo scopes used in inspection and assembly operations with a max. usable magnification of around 50X but with very good long working distance.
Re: Any advantage to larger ocular tube size?
Please read legend of Fig 1 in this article:
https://www.microscopyu.com/microscopy- ... l-aperture
The "tube size" you were referring there is a measure of the eye tube WAY BEHIND front lens (microscope objective). Some microscope objectives do have iris that can limit aperture WITHIN their bodies, but not after.
https://www.microscopyu.com/microscopy- ... l-aperture
The "tube size" you were referring there is a measure of the eye tube WAY BEHIND front lens (microscope objective). Some microscope objectives do have iris that can limit aperture WITHIN their bodies, but not after.
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watchmaker
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Re: Any advantage to larger ocular tube size?
Of course. But the more light allowed through the occular, the brighter the real image formed on the retina. No different from using a 2 inch focuser/eyepiece on a 6 inch refractor rather than an 1.25 inch focuser/eyepiece. The 2 inch will always yield an image with greater brightness and contrast. It is allowing more light from the objective (the 6 inch front lens).
Anyway, what is your understanding of the purpose of 30mm eyetubes as opposed to 23 mm eyetubes? Are 30mm oculars all field stopped to 23 MM?
Regards
Anyway, what is your understanding of the purpose of 30mm eyetubes as opposed to 23 mm eyetubes? Are 30mm oculars all field stopped to 23 MM?
Regards
Re: Any advantage to larger ocular tube size?
It depends on the good (sufficiently corrected) image cone size projected by your specific objective. If objective projects a well-corrected image cone of 18 mm, then 23 mm vs 30 mm eyepiece does not really matter (30 mm won't let in more light than 23 mm in that case, since 23 mm may already be more than big enough). Using an oversized eyepiece on small image cone may even make image poor at edge.
30 mm eye tube does provide more field width, and pass through more light, if your objective projects well-corrected image cone more than 23 mm. But I doubt all 30 mm eyepieces stop at 23 mm field size. Just like 23 mm eyepieces commonly stop anywhere between 16-20 mm field, though many stop at 18 mm. Sharpness, correction and flatness at the field edge will differ too, even if field sizes are the same.
30 mm eye tube does provide more field width, and pass through more light, if your objective projects well-corrected image cone more than 23 mm. But I doubt all 30 mm eyepieces stop at 23 mm field size. Just like 23 mm eyepieces commonly stop anywhere between 16-20 mm field, though many stop at 18 mm. Sharpness, correction and flatness at the field edge will differ too, even if field sizes are the same.
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watchmaker
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Re: Any advantage to larger ocular tube size?
Yet, the Nikon 30mm occulars I have are field stopped to 23mm. Hence my question. Are all 30mm occulars really just 23mm occulars in a larger case?
The Nikon occulars I have are machined from the solid (except for the cell cap). Seat for the lens cell; 30mm mounting OD, with a through bore for the light path to the lens, with a machined field stop that reduces the ID to 23mm.
Not really up for argument; it is what it is. So I am asking people who have practical experience with equipping microscopes if there is a reason to look for 3omm eyepieces when I can turn bushings to use with 23mm eyepieces.
The Nikon occulars I have are machined from the solid (except for the cell cap). Seat for the lens cell; 30mm mounting OD, with a through bore for the light path to the lens, with a machined field stop that reduces the ID to 23mm.
Not really up for argument; it is what it is. So I am asking people who have practical experience with equipping microscopes if there is a reason to look for 3omm eyepieces when I can turn bushings to use with 23mm eyepieces.
Re: Any advantage to larger ocular tube size?
I just miked the ID of one of my 30mm oculars and it measured 27mm.. So I guess not all are..watchmaker wrote:Yet, the Nikon 30mm occulars I have are field stopped to 23mm. Hence my question. Are all 30mm occulars really just 23mm occulars in a larger case?
The Nikon occulars I have are machined from the solid (except for the cell cap). Seat for the lens cell; 30mm mounting OD, with a through bore for the light path to the lens, with a machined field stop that reduces the ID to 23mm.
Not really up for argument; it is what it is. So I am asking people who have practical experience with equipping microscopes if there is a reason to look for 3omm eyepieces when I can turn bushings to use with 23mm eyepieces.
BillT
Re: Any advantage to larger ocular tube size?
There are a variety of variables in this discussion that are becoming somewhat confusing, at least to me.
If you want to compare the eyepieces that fit the 30mm tube to the 23mm tube respectively you need to keep the other aspects of the comparison the same. If you are using a 15X eyepiece that that has a 23mm field (30mm tube) you have the advantage of a much larger field than what the 15X eyepiece in a 23mm tube would provide as they are usually around 15mm or 16mm. If, on the other hand, you want a 10X eyepiece in the 30mm tube the possibilities for a larger field are available (as BillT mentioned). Although I have no experience with an eyepiece with a 27mm field I do have some Nikons that have a 25mm field, but they work only within the parameters of the microscope design.
Very often, if not always, the design of the eyepiece considers the design of the objectives. Sometimes the design of the eyepiece enhances the obvious aspects of the microscopes view by limiting the defects of the objectives.... this hardly resolves the issue, but is fun to discuss.
If you want to compare the eyepieces that fit the 30mm tube to the 23mm tube respectively you need to keep the other aspects of the comparison the same. If you are using a 15X eyepiece that that has a 23mm field (30mm tube) you have the advantage of a much larger field than what the 15X eyepiece in a 23mm tube would provide as they are usually around 15mm or 16mm. If, on the other hand, you want a 10X eyepiece in the 30mm tube the possibilities for a larger field are available (as BillT mentioned). Although I have no experience with an eyepiece with a 27mm field I do have some Nikons that have a 25mm field, but they work only within the parameters of the microscope design.
Very often, if not always, the design of the eyepiece considers the design of the objectives. Sometimes the design of the eyepiece enhances the obvious aspects of the microscopes view by limiting the defects of the objectives.... this hardly resolves the issue, but is fun to discuss.
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watchmaker
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Re: Any advantage to larger ocular tube size?
Bill's reply answers the question. 30mm oculars are not all beefed up 23 mm oculars. Thanks Bill. I did just find a pair of Olympus that use a thin wall tube and do not appear to be field stopped.
FWIW, as a photographer, I fully understand "sweet spots" of a lens. I never understood why people sold their Nikon film lenses rather than use them on the say the DX sensor. You were using the best part of an FX lens on the smaller DX sensor!
It just is very surprising to find Nikon "crippled" this lens. Would have thought they would take advantage of all the room provided by a 30mm tube.
FWIW, as a photographer, I fully understand "sweet spots" of a lens. I never understood why people sold their Nikon film lenses rather than use them on the say the DX sensor. You were using the best part of an FX lens on the smaller DX sensor!
It just is very surprising to find Nikon "crippled" this lens. Would have thought they would take advantage of all the room provided by a 30mm tube.
Re: Any advantage to larger ocular tube size?
Nikon probably did not want to put on a bigger / better / more expensive objective for this model, and they happened to have extra 30 mm tubes/casing at hand? Production logistics, to put it subtly 
I wish Nikon had Dewey as their CEO - it would be a win for us microscopists, at least.
Many other manufacturers have done similar things. Like, putting a NA 0.65 objective on a scope, without providing a condenser to really realize that resolving power.
I wish Nikon had Dewey as their CEO - it would be a win for us microscopists, at least.Many other manufacturers have done similar things. Like, putting a NA 0.65 objective on a scope, without providing a condenser to really realize that resolving power.
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watchmaker
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Re: Any advantage to larger ocular tube size?
Ok. Here is what I found and like. I purchased a pair of Olympus 10X22 eyepieces and a a pair of Amscope 10x Extra widefield (NA measures 25MM). I will be using the Amscope. Very bright and high contrast; plus the EP is much better than the Olympus. Paid $75 for the Olympus, $29 for the Amscope. Both are coated optics; very surprised at the quality of the Amscope. The Olympus are darker to my eyes and the EP is very short.
Regards,
Dewey
Regards,
Dewey
Re: Any advantage to larger ocular tube size?
Morning, Dewey. You might want to wait til after your cataracts are fixed. Everything is brighter,
and a wonderful color shift occurs.
Dale
and a wonderful color shift occurs.
Dale
B&L Stereozoom 4. Nikon E600. AO Biostar 1820.
Re: Any advantage to larger ocular tube size?
Nikon makes 10X/26.5 mm eyepieces. Olympus does as well. Zeiss makes 10X/25 eyepieces. When combined with larger objectives the results are quite astounding.
Not all Stereoscopes were designed to use the larger field eyepieces, even though the 30 mm tubes will accept them.
The Nikon SMZ-U and the Zeiss SV8 and SR utilize the larger field eyepieces and the results are clearly seen.
The Nikon SMZ-10A I believe can use the larger eyepieces. However, the older SMZ's can not. The field will be greatly reduced.
However simply putting a larger field eyepiece in a 30 mm tube where the objective is not sized to take advantage does little. The larger field eyepieces are quite expensive. The Amscope eyepiece are to be honest poorly made. I have several sets and all have delaminated after about 2 years. Initially they were quite good. Perhaps as good as any from the Big 5. It could be I received a bad lot.
The AO Stereo Stars tend to have less light gathering ability due to the smaller objective lenses. Although they are quite good. The AO 580 has the best optics of the AO line. However for the brightest image the cycloptic, believe it or not, is superior to the 580 although magnification is limited to 25x without resorting to 15 or 20 X eyepieces.
Not all Stereoscopes were designed to use the larger field eyepieces, even though the 30 mm tubes will accept them.
The Nikon SMZ-U and the Zeiss SV8 and SR utilize the larger field eyepieces and the results are clearly seen.
The Nikon SMZ-10A I believe can use the larger eyepieces. However, the older SMZ's can not. The field will be greatly reduced.
However simply putting a larger field eyepiece in a 30 mm tube where the objective is not sized to take advantage does little. The larger field eyepieces are quite expensive. The Amscope eyepiece are to be honest poorly made. I have several sets and all have delaminated after about 2 years. Initially they were quite good. Perhaps as good as any from the Big 5. It could be I received a bad lot.
The AO Stereo Stars tend to have less light gathering ability due to the smaller objective lenses. Although they are quite good. The AO 580 has the best optics of the AO line. However for the brightest image the cycloptic, believe it or not, is superior to the 580 although magnification is limited to 25x without resorting to 15 or 20 X eyepieces.
Re: Any advantage to larger ocular tube size?
Oh I should mention I recently sold a Zeiss SV8 to a jewelry maker and he loves it.
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apochronaut
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Re: Any advantage to larger ocular tube size?
It is obvious that a larger piece of glass will theoretically provide a wider brighter f.o.v. but that as einman points out , is limited by the optical design.
Eyepieces cannot create brightness, they can only transmit and therefore preserve what they are sent. In the case of f.o.v.,a more sophisticated 23mm design could easily out perform a simple 30mm design. In the case of aberrations, while the curvature of field is less apparent, with a 30mm eyepiece, and therefore aberration control easier to obtain with a simple design. a more sophisticated design in a 23mm eyepiece could easily be brighter and freer from distortion.
This is seen with astronomy equipment , where unlike microscope designs, the eyepiece designs are stated on the barrel. Some astronomical eyepieces, such as Naglers, in the 1 1/4" format, can easily have a much wider f.o.v. and outperform other eyepiece designs with a 2" barrel.
Historically, microscope eyepieces were simple Huygens designs. If you wanted a wider field, they would be a Ramsden and if you wanted superior colour correction and sharpness, Orthoscopics might be employed. These all relate to the designs for telescopes. As an example, Spencer utilized 31mm huygens eyepieces for their entomological microscopes( now called stereo) up until w.w. II but began a steady conversion, beginning with Ramsden 23mm designs, through several proprietary multi-element 23mm designs up to and including those used on the Stereostar 580, their last flagship stereo microscope, which for it's time, provided exceptional value. AO, certainly had the wherewithall to produce a stereo microscope with a wider field, and a brighter and more resolved image but it might have been a hard sell, at the price that it would have had to have been. Just the wider field eyepieces alone, would have vaulted the microscope into an unrealistic price bracket, as is evidenced by the B & L circumstance.
Bausch & Lomb, AO's direct domestic competitor, produced a similar line of microscopes. The stereozoom line, culminating in the stereozoom 7, also used 23mm w.f. proprietary oculars. However, B & L, in addition to competing in the consumer stereo microscope market , had a military contract for aerial surveillance microscopes based on the stereozoom line. All of a sudden the market has changed and despite the basic microscope design incorporating 23mm ocular tubes, the sky is the limit , when it comes to eyepiece design. Anything to spy on those Ruskies, right?
AO, might have bid on the contract but they didn't end up producing it and that for sure would be the measure of how far a system could be extended and be paid for.
So, with B & L, the stops were out somewhat on the stereozoom line. They had collimating w.f. 10x eyepieces and 7 element 15x u.w.f.( 20mm at 15x or the equivalent of about 30mm at 10x) eyepieces with 23mm tubes. The 15x were about 2,000.00 a pair in their day.
Those show up pretty regularly on ebay and are a nice snag, at the prices they now sell for.
Eyepieces cannot create brightness, they can only transmit and therefore preserve what they are sent. In the case of f.o.v.,a more sophisticated 23mm design could easily out perform a simple 30mm design. In the case of aberrations, while the curvature of field is less apparent, with a 30mm eyepiece, and therefore aberration control easier to obtain with a simple design. a more sophisticated design in a 23mm eyepiece could easily be brighter and freer from distortion.
This is seen with astronomy equipment , where unlike microscope designs, the eyepiece designs are stated on the barrel. Some astronomical eyepieces, such as Naglers, in the 1 1/4" format, can easily have a much wider f.o.v. and outperform other eyepiece designs with a 2" barrel.
Historically, microscope eyepieces were simple Huygens designs. If you wanted a wider field, they would be a Ramsden and if you wanted superior colour correction and sharpness, Orthoscopics might be employed. These all relate to the designs for telescopes. As an example, Spencer utilized 31mm huygens eyepieces for their entomological microscopes( now called stereo) up until w.w. II but began a steady conversion, beginning with Ramsden 23mm designs, through several proprietary multi-element 23mm designs up to and including those used on the Stereostar 580, their last flagship stereo microscope, which for it's time, provided exceptional value. AO, certainly had the wherewithall to produce a stereo microscope with a wider field, and a brighter and more resolved image but it might have been a hard sell, at the price that it would have had to have been. Just the wider field eyepieces alone, would have vaulted the microscope into an unrealistic price bracket, as is evidenced by the B & L circumstance.
Bausch & Lomb, AO's direct domestic competitor, produced a similar line of microscopes. The stereozoom line, culminating in the stereozoom 7, also used 23mm w.f. proprietary oculars. However, B & L, in addition to competing in the consumer stereo microscope market , had a military contract for aerial surveillance microscopes based on the stereozoom line. All of a sudden the market has changed and despite the basic microscope design incorporating 23mm ocular tubes, the sky is the limit , when it comes to eyepiece design. Anything to spy on those Ruskies, right?
AO, might have bid on the contract but they didn't end up producing it and that for sure would be the measure of how far a system could be extended and be paid for.
So, with B & L, the stops were out somewhat on the stereozoom line. They had collimating w.f. 10x eyepieces and 7 element 15x u.w.f.( 20mm at 15x or the equivalent of about 30mm at 10x) eyepieces with 23mm tubes. The 15x were about 2,000.00 a pair in their day.
Those show up pretty regularly on ebay and are a nice snag, at the prices they now sell for.
Last edited by apochronaut on Wed Nov 30, 2016 12:32 am, edited 1 time in total.
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watchmaker
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- Joined: Mon Nov 21, 2016 7:56 pm
Re: Any advantage to larger ocular tube size?
Thanks all; this has been most useful. Disappointed my Amscopes may fall apart in time; will not hurry to sell the Olympus eyepieces. I really do like the image from the Amscopes though.
I use the 570 for turning between centers and the SMZ1B at the bench for assembly/disassembly with a .5x barlow. This gives me a good working distance and the angle of the 1b eyetubes puts my body in the right place.
I may use the workbench scope less when I get my cataracts done; but it will be nice to have it right there for parts inspection. The loupe is more convenient than the scope for bench work, but using a 10x at the lathe is a bit bothersome and I get a much better picture with 570 at that station.
Regards,
Dewey
I use the 570 for turning between centers and the SMZ1B at the bench for assembly/disassembly with a .5x barlow. This gives me a good working distance and the angle of the 1b eyetubes puts my body in the right place.
I may use the workbench scope less when I get my cataracts done; but it will be nice to have it right there for parts inspection. The loupe is more convenient than the scope for bench work, but using a 10x at the lathe is a bit bothersome and I get a much better picture with 570 at that station.
Regards,
Dewey
Re: Any advantage to larger ocular tube size?
I agree with Apo. Eyepieces between compound and stereoscope are not always directly interchangeable. For example with the B&L SZ7 You can put a 10X/23 widefield eyepiece intended for a compound scope into its ocular tubes and actually have a smaller field of view then the 10X/18 eyepieces designed for the scope. A simple experiment I did to compare eyepieces.