Hello...
I have been following the forums for a bit now trying to learn as much as I can about photomicrography and scopes before I take the plunge. My first question is in regards to modern Infinity based microscopes, and older well equipped systems - like the Meiji ML2000 + Olympus S Plan APO's Mr. Krebs uses.
Am I correct in thinking that an older system (and I mean no older than the above) would match the image quality of an Infinity based system - if using comparable objectives and scopes - for instance a Meiji ML2000 w/ Olympus S Plan APOs vs. a ML3000 w/ Olym U Plan APOs?
When it comes down to it, corrections happening in the infinity system's objectives still take place in the older setup - just at a different place in the microscope... *scratches head*
Infinity Systems
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Basically, high-quality older systems are as "good" as infinity systems. The infinity system offers more flexiblity in scope design - you can place as much between the objective and the image plane because the center of the infinity system has no focal length and therefore no set distance requirements. Kind of neat if you think about it.
Will
Actually, it has nothing to do with the working space under the objective, but the optical distance between the ojective and image plane, which would be infinite rather than having a specified tube length in the 160mm to 210mm range. This lets the designer great freedom in the number of filter ports for example or the placement of camera ports. It is really an under-the-hood thing rather than anything that affects the operator. You cannot tell if a scope has infinity optics by just looking at it.
This may help:
http://www.microscopyu.com/articles/gen ... tions.html
This may help:
http://www.microscopyu.com/articles/gen ... tions.html
Will
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Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
John... Welcome aboard!
I see Will has already answered. I'll just add a few other points and thoughts.
One advantage to "infinity" scopes is that by the time the image reaches the eyepiece no additional aberration correction is required. So the choice of relay optics is greatly simplified... they should be of high optical quality, but do not need proprietary "correction" for the objectives. (And it's also possible to "place" the image directly onto the sensor with "lens-less" cameras since you have a fully corrected real image at the eypiece location)
With infinity designs, it is much easier for manufacturers to place "intermediate" pieces between the objective and the eyepiece (such as DIC sliders or epi-illuminators, and as Will said, camera ports). With finite systems these pieces altered the tube length, and addition optics had to be included. For example... I was fortunate to locate an Olympus BHS stand with DIC that I could afford. The intermediate piece for DIC has additional optics to accomodate the increased distance between objective and eyepiece. These optics give a magnification increase of 1.25X, which at first glance may seem like a good thing, but in reality it forced me to change my relay optics as the magnification became too great, and I was recording a section of the view ("field number") that was too small.
I see Will has already answered. I'll just add a few other points and thoughts.
I would be extremely cautious about using one manufacturers objectives on a different manufacturers stand with "infinity" objectives. The tube lens does actually provide final corrections with some (but not all!) "infinity" systems (sort of like the final corrections made with the eyepiece in finite systems). With finite objectives, there was no problem using objectives from one manufacturer on anothers stand provided the tube length was proper, and the eyepieces were correctly matched to the objectives.a ML3000 w/ Olym U Plan APOs
One advantage to "infinity" scopes is that by the time the image reaches the eyepiece no additional aberration correction is required. So the choice of relay optics is greatly simplified... they should be of high optical quality, but do not need proprietary "correction" for the objectives. (And it's also possible to "place" the image directly onto the sensor with "lens-less" cameras since you have a fully corrected real image at the eypiece location)
With infinity designs, it is much easier for manufacturers to place "intermediate" pieces between the objective and the eyepiece (such as DIC sliders or epi-illuminators, and as Will said, camera ports). With finite systems these pieces altered the tube length, and addition optics had to be included. For example... I was fortunate to locate an Olympus BHS stand with DIC that I could afford. The intermediate piece for DIC has additional optics to accomodate the increased distance between objective and eyepiece. These optics give a magnification increase of 1.25X, which at first glance may seem like a good thing, but in reality it forced me to change my relay optics as the magnification became too great, and I was recording a section of the view ("field number") that was too small.
Thank you Will and Charles for the info and corrections. AND the welcome to the forum! 
An Olympus Rep provided the following info on tube length's:
"Off hand I would say no to the lens compatibility issue between microscope brands (especially Meiji). Zeiss and Olympus do match however, so I am not certain of the mixing of parts here. Off hand I would say no, as Meiji was based on Nikon 160mm tube lens and Zeiss and Olympus are 180mm."
This was confirmed by a Meiji rep. who said that another brands optics had to be "DIN" compatible - and DIN is 160mm.
So if I go with a finite system, every time I change my lighting/contrast technique, be it DIC or Dark field, etc. the magnification associated with this addition would be added to my photo eye-piece's mag. If my photo eye-piece is 2.5x, my total mag. to camera sensor might be 3.5x, 4.5x etc... thus effectively cropping down the amount of image I can capture. The only way to compensate would be to have several photo eye- pieces, at varying magnifications, that could compensate for increases in magnification?
It seems simpler to try other contrast/lighting techniques with an infinity system, but the cost to get in one w/ APO optics is quite outstanding (12K for an BX41 w/ U Plan APOs). I could probably buy 2 finite scopes w/ used APO optics for that price.
I welcome further corrections and suggestions!
Thanks,
John
An Olympus Rep provided the following info on tube length's:
"Off hand I would say no to the lens compatibility issue between microscope brands (especially Meiji). Zeiss and Olympus do match however, so I am not certain of the mixing of parts here. Off hand I would say no, as Meiji was based on Nikon 160mm tube lens and Zeiss and Olympus are 180mm."
This was confirmed by a Meiji rep. who said that another brands optics had to be "DIN" compatible - and DIN is 160mm.
So if I go with a finite system, every time I change my lighting/contrast technique, be it DIC or Dark field, etc. the magnification associated with this addition would be added to my photo eye-piece's mag. If my photo eye-piece is 2.5x, my total mag. to camera sensor might be 3.5x, 4.5x etc... thus effectively cropping down the amount of image I can capture. The only way to compensate would be to have several photo eye- pieces, at varying magnifications, that could compensate for increases in magnification?
It seems simpler to try other contrast/lighting techniques with an infinity system, but the cost to get in one w/ APO optics is quite outstanding (12K for an BX41 w/ U Plan APOs). I could probably buy 2 finite scopes w/ used APO optics for that price.
I welcome further corrections and suggestions!
Thanks,
John
I am a little confused? Is there a specific magnification you want to work at? Are you only going to have one objective?
Most microscopes are fitted with several objectives to work around field of view. I have an Olympus scope and my DIC prisms only change the magnification by 1.1x. I have never found this to be a problem.
Yes, you can used different photo eyepieces. I find just changing objectives easier. I also know that Olympus made a unit to vary magnification for a little more control (and mounts just above the objectives).
Sorry. From your post I am not sure I see what you need. I would work this problem by starting at the magnifications you want to work at, and then find the system that will give you that. I guess the reason I am confused is microscopes are fairly flexible devices already. It is just a matter of having several objectives that give a good range of magnifications - I use a 5x, 10x, 20x, and 40x set, which is a fairly standard spread. Now if picking up four APO objectives is too much now, I would suggest getting a 10x APO (my most used objective magnification) and simply fill the nosepiece with Plan objectives at different mags. That will give you a little experience and then you can replace them with APO objectives as time and the bank account permit.
BTW, why APO objectives?
Most microscopes are fitted with several objectives to work around field of view. I have an Olympus scope and my DIC prisms only change the magnification by 1.1x. I have never found this to be a problem.
Yes, you can used different photo eyepieces. I find just changing objectives easier. I also know that Olympus made a unit to vary magnification for a little more control (and mounts just above the objectives).
Sorry. From your post I am not sure I see what you need. I would work this problem by starting at the magnifications you want to work at, and then find the system that will give you that. I guess the reason I am confused is microscopes are fairly flexible devices already. It is just a matter of having several objectives that give a good range of magnifications - I use a 5x, 10x, 20x, and 40x set, which is a fairly standard spread. Now if picking up four APO objectives is too much now, I would suggest getting a 10x APO (my most used objective magnification) and simply fill the nosepiece with Plan objectives at different mags. That will give you a little experience and then you can replace them with APO objectives as time and the bank account permit.
BTW, why APO objectives?
Will
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Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
John,
If you have not seen it, an excellent page for you to read would be:
http://micro.magnet.fsu.edu/primer/anat ... intro.html
I also have some info on relay optics that might be useful to you at:
http://www.krebsmicro.com
The fact that intermediate pieces usually come with additional "magnification" with finite scopes is not as complicated as you make it sound, but you must factor it into the relay optics you use with a camera to determine the FN ("field number") you record on the sensor/film. I think that generally most people leave the "intermediate" piece attached when changing lighting methods. For example, when I do brightfield or darkfield I do not remove the DIC intermediate piece, I simply pull the DIC slider out so it is not in the light path.
If you have not seen it, an excellent page for you to read would be:
http://micro.magnet.fsu.edu/primer/anat ... intro.html
I also have some info on relay optics that might be useful to you at:
http://www.krebsmicro.com
The fact that intermediate pieces usually come with additional "magnification" with finite scopes is not as complicated as you make it sound, but you must factor it into the relay optics you use with a camera to determine the FN ("field number") you record on the sensor/film. I think that generally most people leave the "intermediate" piece attached when changing lighting methods. For example, when I do brightfield or darkfield I do not remove the DIC intermediate piece, I simply pull the DIC slider out so it is not in the light path.
Sorry guys, my wife had a baby at the beginning of Nov. and I haven’t had a chance to come back since. 
Will: APO because I want to shoot with the best corrected objectives, but I am realizing now that something in the middle will probably suite me just fine (like canon 'L' series vs. Leica). Thanks for the info on the spread you use.
Charles: Wow that article on infinity systems is going to take some digesting, I think it will be easier to see in my mind once I get the scope and play around with it. I have been studying all the articles on your site - very helpful. Now you just need to add your macro setup
-John
Will: APO because I want to shoot with the best corrected objectives, but I am realizing now that something in the middle will probably suite me just fine (like canon 'L' series vs. Leica). Thanks for the info on the spread you use.
Charles: Wow that article on infinity systems is going to take some digesting, I think it will be easier to see in my mind once I get the scope and play around with it. I have been studying all the articles on your site - very helpful. Now you just need to add your macro setup
-John
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Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact: