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ZOOM STEREOSCOPES

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  • PAT CARVILL
    I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought
    Message 1 of 11 , Sep 1, 2009
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      I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
       
      One brand I have been looking at is Optika. Does anyone have any experience of them?
       
      Pat




      [Non-text portions of this message have been removed]
    • pennine56
      ... Hello Pat There s two main types of stereo zoom, the paired objective design and the common main objective (CMO). In each type I think there s both the
      Message 2 of 11 , Sep 2, 2009
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        --- In Microscope@yahoogroups.com, PAT CARVILL <patvcarvill@...> wrote:
        >
        > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
        >  
        > One brand I have been looking at is Optika. Does anyone have any experience of them?
        >  
        > Pat
        >

        Hello Pat

        There's two main types of stereo zoom, the paired objective design and the common main objective (CMO). In each type I think there's both the click wheel of mags and the continuously variable mag.

        They each seem to have their pros and cons. Molecular Expressions has an excellent overview of the types at

        http://www.microscopyu.com/articles/stereomicroscopy/stereointro.html

        I've always been a bit wary of cheap CMO designs if transmitted light was main interest as they use the edge of the main objective. I was quite surprised how much aberration there was on a modern Leica MS5 with achro' CMO in transmitted light with dense object edges like insects, a very noticeable yellow fringing. Superb with incident though.

        My own is a Meiji EMZ1 with the paired objectives but continuously variable zoom.

        I've never found much benefit of going much above 500x the stereo's NA. A typical NA of a lab workhorse achromatic like the EMZ1 is about 0.07 - 0.08 so about 30 - 40x max. My EMZ1 I rarely use at 30x, the image gets bigger but not in my view better. About 25x is my max.

        The older paired objective designs and the budget stereos can have very low NAs ca 0.02. The difference when I upgraded from my Meiji student to an secondhand EMZ1 was striking.

        The NAs aren't always stated but believe they can be measured quite accurately from true working distance to first element and diameter of paired objective using the NA equation. For CMO the estimated size of entrance port for each objective, not the diameter of CMO. I tried this for a Leica CMO MS5 and got very close to maker's stated NA. Ultimately the NA is a key aspect I think. If your Kyowa has higher NA than a modern one.

        I'm not familiar with Optika http://www.optikamicroscopes.com/
        Their website suggests they produce in Europe.

        with regards
        David
      • twcoffey1
        Pat, I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the
        Message 3 of 11 , Sep 2, 2009
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          Pat,
          I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the field will be useful.
          Ted

          --- In Microscope@yahoogroups.com, PAT CARVILL <patvcarvill@...> wrote:
          >
          > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
          >  
          > One brand I have been looking at is Optika. Does anyone have any experience of them?
          >  
          > Pat
          >
          >
          >
          >
          > [Non-text portions of this message have been removed]
          >
        • fred.hebard
          Whether or not distortion occurs at high magnification in a stereo zoom depends strongly on the microscope. Certainly it doesn t occur in the high-end
          Message 4 of 11 , Sep 2, 2009
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            Whether or not distortion occurs at high magnification in a stereo zoom depends strongly on the microscope. Certainly it doesn't occur in the high-end microscopes.

            --- In Microscope@yahoogroups.com, "twcoffey1" <twcoffey@...> wrote:
            >
            > Pat,
            > I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the field will be useful.
            > Ted
            >
            > --- In Microscope@yahoogroups.com, PAT CARVILL <patvcarvill@> wrote:
            > >
            > > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
            > >  
            > > One brand I have been looking at is Optika. Does anyone have any experience of them?
            > >  
            > > Pat
            > >
            > >
            > >
            > >
            > > [Non-text portions of this message have been removed]
            > >
            >
          • PAT CARVILL
            I am grateful to all those who took the trooble to reply.   I can understand that the combination of (I assume) necessarily more complicated optics in a
            Message 5 of 11 , Sep 2, 2009
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              I am grateful to all those who took the trooble to reply.
               
              I can understand that the combination of (I assume) necessarily more complicated optics in a zoomand price constraints could make it difficult to optimise quality above say 30X.
               
              But is this a problem unique to zoomz?  ie would I be likely to get the same distortion etc in a comparably priced non zoom at say 40X or 50X? In other words, is the zoom facility in itself making things worse?
               
              Pat

              --- On Wed, 2/9/09, fred.hebard <Fred@...> wrote:


              From: fred.hebard <Fred@...>
              Subject: [Microscope] Re: ZOOM STEREOSCOPES
              To: Microscope@yahoogroups.com
              Date: Wednesday, 2 September, 2009, 2:36 PM


               



              Whether or not distortion occurs at high magnification in a stereo zoom depends strongly on the microscope. Certainly it doesn't occur in the high-end microscopes.

              --- In Microscope@yahoogro ups.com, "twcoffey1" <twcoffey@.. .> wrote:
              >
              > Pat,
              > I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the field will be useful.
              > Ted
              >
              > --- In Microscope@yahoogro ups.com, PAT CARVILL <patvcarvill@ > wrote:
              > >
              > > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
              > >  
              > > One brand I have been looking at is Optika. Does anyone have any experience of them?
              > >  
              > > Pat
              > >
              > >
              > >
              > >
              > > [Non-text portions of this message have been removed]
              > >
              >



















              [Non-text portions of this message have been removed]
            • twcoffey1
              Pat, Zoom lens configurations have limits. For example: It may be possible to create a relatively distortion free zoom range from say 7x to 30x at a
              Message 6 of 11 , Sep 2, 2009
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                Pat,
                Zoom lens configurations have limits. For example: It may be possible to create a relatively distortion free zoom range from say 7x to 30x at a reasonable cost or perhaps a 20x to 80x or other combination but to think of a zoom range from 7x to 70x when the aperture is large and the budget restricted is a stretch without compromising the image. If you look at the photographic zoom len ranges available today you see such limits.
                This is caused by the amount of lens spacing variations within the lens assembly and the optical limitation of the individual elements. Zoom lenses of very small aperture are easier to design for large zoom ranges and you will find 20x zooms ranges on very small aperture cameras. You will find that most larger aperture lenses have limited zoom range of around 3x.
                Non-Zoom configurations can be designed over a very large range of magnifications with low distortion but you have to give up the convenience of the zoom. In photography the consumer will usually tolerate more distortion than the scientist in the laboratory.
                It is like most other things when quality, price, and convenience are compromised in some fashion.
                In short fixed magnifications are possible up to the resolution limits of optical microscopy around 1000X but for zoom scopes don't expect to zoom range to be more than 4x from low to high.
                Ted


                --- In Microscope@yahoogroups.com, PAT CARVILL <patvcarvill@...> wrote:
                >
                > I am grateful to all those who took the trooble to reply.
                >  
                > I can understand that the combination of (I assume) necessarily more complicated optics in a zoomand price constraints could make it difficult to optimise quality above say 30X.
                >  
                > But is this a problem unique to zoomz?  ie would I be likely to get the same distortion etc in a comparably priced non zoom at say 40X or 50X? In other words, is the zoom facility in itself making things worse?
                >  
                > Pat
                >
                > --- On Wed, 2/9/09, fred.hebard <Fred@...> wrote:
                >
                >
                > From: fred.hebard <Fred@...>
                > Subject: [Microscope] Re: ZOOM STEREOSCOPES
                > To: Microscope@yahoogroups.com
                > Date: Wednesday, 2 September, 2009, 2:36 PM
                >
                >
                >  
                >
                >
                >
                > Whether or not distortion occurs at high magnification in a stereo zoom depends strongly on the microscope. Certainly it doesn't occur in the high-end microscopes.
                >
                > --- In Microscope@yahoogro ups.com, "twcoffey1" <twcoffey@ .> wrote:
                > >
                > > Pat,
                > > I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the field will be useful.
                > > Ted
                > >
                > > --- In Microscope@yahoogro ups.com, PAT CARVILL <patvcarvill@ > wrote:
                > > >
                > > > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X.  But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
                > > >  
                > > > One brand I have been looking at is Optika. Does anyone have any experience of them?
                > > >  
                > > > Pat
                > > >
                > > >
                > > >
                > > >
                > > > [Non-text portions of this message have been removed]
                > > >
                > >
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              • forgerii
                I have a B&L Stereozoom 7 from eBay which I had rebuilt by a professiuonal. I routinely use it with a pair of matched 15X WF eyepieces. At full Zoom, that is
                Message 7 of 11 , Sep 2, 2009
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                  I have a B&L Stereozoom 7 from eBay which I had rebuilt by a professiuonal. I routinely use it with a pair of matched 15X WF eyepieces. At full Zoom, that is 105X. I have carefully calibrated it is several directions and found no distortion that I could see. The images are crisp and clear, even at full zoom.

                  The school where I taught had some Chinese-made scopes that did have visible distortion at 45X.
                • twcoffey1
                  I think if you recalculate you will find that the 15x eyepiece gives you are range of 10.5 to 45X since a 10X eyepiece gives you 7 to 30X. In order to see the
                  Message 8 of 11 , Sep 2, 2009
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                    I think if you recalculate you will find that the 15x eyepiece gives you are range of 10.5 to 45X since a 10X eyepiece gives you 7 to 30X.
                    In order to see the distortion at the maximum magnification you need a ruled grid place on the stage and look at the squares in the center of the field compared to the edges of the field. You should see distortion at the edges in that the squares of the grid will not be square.
                    Ted

                    --- In Microscope@yahoogroups.com, "forgerii" <forgerii@...> wrote:
                    >
                    > I have a B&L Stereozoom 7 from eBay which I had rebuilt by a professiuonal. I routinely use it with a pair of matched 15X WF eyepieces. At full Zoom, that is 105X. I have carefully calibrated it is several directions and found no distortion that I could see. The images are crisp and clear, even at full zoom.
                    >
                    > The school where I taught had some Chinese-made scopes that did have visible distortion at 45X.
                    >
                  • gordoncouger
                    Hi Pat, The distortion is unavoidable depending on the how the microscope is built to get the two off axis views Greenough or XXXXXX so you see a 3D image.
                    Message 9 of 11 , Sep 2, 2009
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                      Hi Pat,

                      The distortion is unavoidable depending on the how the microscope is built to get the two off axis views Greenough or XXXXXX so you see a 3D image. There are a hand full stereo/macro scopes that view the subject using 3 axixs one being streight down the center for photography that doesn't have any destortion from looking at the subject from and angle or off the central axsis of the lens.

                      Nikon's Microscope U's page Introduction to Stereomicroscopy
                      http://nikon.magnet.fsu.edu/articles/stereomicroscopy/stereointro.html

                      I spent a long time looking for the page on Michael Davidson's page, "Optical Microscopy Primer" so I just included the links as they cover many aspects of distortions and aberrations.

                      "Optical Microscopy Primer"
                      http://micro.magnet.fsu.edu/primer/index.html

                      Common Optical Defects in Lens Systems (Aberrations)
                      http://micro.magnet.fsu.edu/primer/lightandcolor/opticalaberrations.html

                      Optical Aberrations Interactive Java Tutorials
                      http://micro.magnet.fsu.edu/primer/java/aberrations/curvatureoffield/index.html

                      Bausch & Lomb KAJ Binocular Stereomicroscope
                      http://micro.magnet.fsu.edu/primer/museum/bandlkandj1929.html
                      ====

                      Basic Concepts in Optical Microscopy
                      http://micro.magnet.fsu.edu/primer/anatomy/anatomy.html

                      Light & Color
                      http://micro.magnet.fsu.edu/primer/lightandcolor/index.html
                      http://micro.magnet.fsu.edu/primer/lightandcolor/humanvisionintro.html

                      Optical Microscopy
                      http://micro.magnet.fsu.edu/primer/pdfs/microscopy.pdf

                      Human Vision and Color Perception
                      http://micro.magnet.fsu.edu/primer/lightandcolor/humanvisionintro.html

                      Introduction to Optical Microscopy, Digital Imaging, and Photomicrography
                      http://micro.magnet.fsu.edu/primer/index.html

                      Basic Properties of Digital Images
                      http://micro.magnet.fsu.edu/primer/digitalimaging/digitalimagebasics.html

                      Introduction to Photomicrography
                      http://micro.magnet.fsu.edu/publications/pages/introphoto.html

                      Bibliography
                      http://micro.magnet.fsu.edu/primer/bibliography.html

                      From: © 1998-2009 by Michael W. Davidson and The Florida State University. 
Graphics & Web Programming Team in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory. supported by Olympus, Nikon, Zeiss & Leica

                      Gordon
                      --- In Microscope@yahoogroups.com, PAT CARVILL <patvcarvill@...> wrote:
                      >
                      > I am grateful to all those who took the trooble to reply.
                      >
                      > I can understand that the combination of (I assume) necessarily more complicated optics in a zoomand price constraints could make it difficult to optimise quality above say 30X.
                      >
                      > But is this a problem unique to zoomz? ie would I be likely to get the same distortion etc in a comparably priced non zoom at say 40X or 50X? In other words, is the zoom facility in itself making things worse?
                      >
                      > Pat
                      >
                      > --- On Wed, 2/9/09, fred.hebard <Fred@...> wrote:
                      >
                      >
                      > From: fred.hebard <Fred@...>
                      > Subject: [Microscope] Re: ZOOM STEREOSCOPES
                      > To: Microscope@yahoogroups.com
                      > Date: Wednesday, 2 September, 2009, 2:36 PM
                      >
                      >
                      >
                      >
                      >
                      >
                      > Whether or not distortion occurs at high magnification in a stereo zoom depends strongly on the microscope. Certainly it doesn't occur in the high-end microscopes.
                      >
                      > --- In Microscope@yahoogro ups.com, "twcoffey1" <twcoffey@ .> wrote:
                      > >
                      > > Pat,
                      > > I think you will find that a stereo zoom scope will have objectionable distortion at magnifications above 30X. Above 30X only a small central area of the field will be useful.
                      > > Ted
                      > >
                      > > --- In Microscope@yahoogro ups.com, PAT CARVILL <patvcarvill@ > wrote:
                      > > >
                      > > > I am still planning an upgrade of my 10X and 30X Kyowa scope, and am attracted by a zoom, with magnification up to at least 45X and perhaps 60X. But thought I should just check whether there are any particular disadvantages to zoom scopes, eg do they perhaps offer less optical quality (pound for pound) or reduce the field of view or whatever?
                      > > >
                      > > > One brand I have been looking at is Optika. Does anyone have any experience of them?
                      > > >
                      > > > Pat
                    • Mike Whittome
                      Hi, guys, Just following along with the threads. The zoom 7 is a 7:1 zoom scope. It is 1x to 7x zoom It will give 15x to 105x with the 15x eyepieces installed
                      Message 10 of 11 , Sep 2, 2009
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                        Hi, guys, Just following along with the threads.
                        The zoom 7 is a 7:1 zoom scope.
                        It is 1x to 7x zoom
                        It will give 15x to 105x with the 15x eyepieces installed and 10x to 70x with 10x eyepieces.
                        These scopes are really well built and do offer exceptionally good correction. The scopes new at the end of the 90's were approx. $3k for the body alone (Leica GZ7). There is a lot of glass in there to get the job dome and many adjustments available to the optics to null distortion. This model will work ok even with with 20x eyepieces at 140x.
                         
                        Regards,
                         
                        Mike Whittome
                        optekusa.com

                        --- On Wed, 9/2/09, twcoffey1 <twcoffey@...> wrote:


                        From: twcoffey1 <twcoffey@...>
                        Subject: [Microscope] Re: ZOOM STEREOSCOPES
                        To: Microscope@yahoogroups.com
                        Date: Wednesday, September 2, 2009, 6:04 PM


                         



                        I think if you recalculate you will find that the 15x eyepiece gives you are range of 10.5 to 45X since a 10X eyepiece gives you 7 to 30X.
                        In order to see the distortion at the maximum magnification you need a ruled grid place on the stage and look at the squares in the center of the field compared to the edges of the field. You should see distortion at the edges in that the squares of the grid will not be square.
                        Ted

                        --- In Microscope@yahoogro ups.com, "forgerii" <forgerii@.. .> wrote:
                        >
                        > I have a B&L Stereozoom 7 from eBay which I had rebuilt by a professiuonal. I routinely use it with a pair of matched 15X WF eyepieces. At full Zoom, that is 105X. I have carefully calibrated it is several directions and found no distortion that I could see. The images are crisp and clear, even at full zoom.
                        >
                        > The school where I taught had some Chinese-made scopes that did have visible distortion at 45X.
                        >



















                        [Non-text portions of this message have been removed]
                      • gordoncouger
                        Hi Mike, Unless things have changed a good deal while while I wasn t paying attention. Getting a decent image at 25x with a stereo microscope didn t cost too
                        Message 11 of 11 , Sep 3, 2009
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                          Hi Mike,

                          Unless things have changed a good deal while while I wasn't paying attention. Getting a decent image at 25x with a stereo microscope didn't cost too much getting one that was as good at 50x cost about twice as much and so on with twice as much for 100x and maybe more for 200x.

                          The original post was by a fellow that wanted to pollinate flower on small budget. Now I know one small budget may be $50 bucks and the next may be $5,000 dollars.

                          I have used a GZ7 and their great at 70x and 140x. A lot better and higher contrast than an my AO Cyclopitic at 50x which is low cost solution at $50 to $200 dollars depending on where you buy and how good you bargain.

                          What price range does a GZ7 sell in now?

                          Gordon


                          --- In Microscope@yahoogroups.com, Mike Whittome <optekusa@...> wrote:
                          >
                          > Hi, guys, Just following along with the threads.
                          > The zoom 7 is a 7:1 zoom scope.
                          > It is 1x to 7x zoom
                          > It will give 15x to 105x with the 15x eyepieces installed and 10x to 70x with 10x eyepieces.
                          > These scopes are really well built and do offer exceptionally good correction. The scopes new at the end of the 90's were approx. $3k for the body alone (Leica GZ7). There is a lot of glass in there to get the job dome and many adjustments available to the optics to null distortion. This model will work ok even with with 20x eyepieces at 140x.
                          >  
                          > Regards,
                          >  
                          > Mike Whittome
                          > optekusa.com
                          >
                          > --- On Wed, 9/2/09, twcoffey1 <twcoffey@...> wrote:
                          >
                          >
                          > From: twcoffey1 <twcoffey@...>
                          > Subject: [Microscope] Re: ZOOM STEREOSCOPES
                          > To: Microscope@yahoogroups.com
                          > Date: Wednesday, September 2, 2009, 6:04 PM
                          >
                          >
                          >  
                          >
                          >
                          >
                          > I think if you recalculate you will find that the 15x eyepiece gives you are range of 10.5 to 45X since a 10X eyepiece gives you 7 to 30X.
                          > In order to see the distortion at the maximum magnification you need a ruled grid place on the stage and look at the squares in the center of the field compared to the edges of the field. You should see distortion at the edges in that the squares of the grid will not be square.
                          > Ted
                          >
                          > --- In Microscope@yahoogro ups.com, "forgerii" <forgerii@ .> wrote:
                          > >
                          > > I have a B&L Stereozoom 7 from eBay which I had rebuilt by a professiuonal. I routinely use it with a pair of matched 15X WF eyepieces. At full Zoom, that is 105X. I have carefully calibrated it is several directions and found no distortion that I could see. The images are crisp and clear, even at full zoom.
                          > >
                          > > The school where I taught had some Chinese-made scopes that did have visible distortion at 45X.
                          > >
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