purchasing new eyepiece set...

[stonewhite]

hello

the microscope is an American Optical One-Fifty...

the current eyepiece set is a 10mm WF ('cat. 138')...

the width of the insertion base appears to be 23mm...

we would like to install a new eyepiece set--possibly 25X...

are all eyepiece insertion diameters uniform in width--23mm?

in the eBay item below, where is the '30mm' dimension derived?

http://www.ebay.com/itm/Zeiss-20X-Eyepi ... 2689535681


thanks again...

[mrsonchus]

Hi, simply put, some 'widefield' 'scopes (such as the Leitz Orthoplan and most 'modern' 'scopes) have an eyepiece-tube of 30mm and others of 23mm. An adapter-sleeve can be used to fit a 23mm eyepiece into a 30mm eyepiece-tube but not vice-versa.

If those eyepieces are 30mm, which I think they are, they won't fit into your 'scope's 23mm eyepiece-tubes I'm afraid.

John B.
p.s.
The measurement - i.e. the 23mm or the 30mm - refers to the diameter of the eyepieces/eyepiece-tubes.

[75RR]

This is from the ebay advert:

This set of eyepieces came off an older Zeiss stereo microscope with 30mm eyepiece tubes.

20x and 25x are usually from/for stereo scopes and hence 30mm in diameter - they do not work well on compound scopes due to their high magnification - even if you did manage to make them fit.
Note: Do not mix/confuse 160 tube length microscopes and their eyepieces/objectives with infinity ones.

See post on empty magnification and the difference between eyepieces and objectives: viewtopic.php?f=25&t=4984&p=45460&hilit ... lit#p45460

[75RR]

repeat post

[zzffnn]

Stonewhite,

Welcome to the forum.

I have, for sale, a pair of 25x 23mm diameter eyepieces that came with a very early purchase. They are brand new and have never been used.

They are not comfortable to use though, nor would they provide high quality imaging. In general, no microscopy eyepiece at or above 20x power would.

You can reach me at zzffnn at h0tm8il dot com, if you want those eyepieces for prices cheaper than eBay (which is around $17 shipped for a pair). Change 0 to o and 8 to a for the correct address, please.

[stonewhite]

learning all the time...


I ought to have posted in the 'beginner' column...at any rate (and, having
read the literature on this topic), the 20x or 25x WF eyepiece idea has been discarded
(filed in the 'optical diminishing returns' bin)...

apparently, as we increase the eyepiece magnification, there is a trade-off...

not to press the issue, but what is the 'frontier' of that objective/eyepiece
partnering: would a 15x eyepiece buy me anything in the image quality department...?

or, ought I resign myself to the idea that a 10x eyepiece is the optimum choice in that
pairing (i.e., chosen for a reason) ...?

thanks again, one and all...

[75RR]

... ought I resign myself to the idea that a 10x eyepiece is the optimum choice ...

Pretty much

Re-posting link to Useful Magnification Range:
viewtopic.php?f=5&t=1812#p13933

These are the two relevant paragraphs to your query but you would do well to reread the original post in its entirety:

A quick test is to multiply the NA of an objective by 1000,
then multiply the magnification of the objective by the magnification of the eyepiece,
if the second figure is higher then using that objective with that eyepiece will result in empty magnification.
If it is lower, then using that eyepiece (with that objective) will not result in empty magnification.

Another useful test is to divide the max magnification by the objective's magnification, this gives you the max eyepiece magnification for that objective.
In this case 650/40 = 16. Therefore a 16x eyepiece would be ok (just) but a 20x eyepiece would give empty (too much) magnification with this objective.

In a nutshell, best to think of 10x or 12.5x as the max practical eyepiece magnification, though on occasion (using the formula) one can use up to 16x
If you want more total magnification get a higher magnification objective. That is where the image quality is!

Note: As gekko pointed out - if one has weak eyes (and eventually most of us will) then using a 16x eyepiece rather than a 12.5x can be beneficial.

[stonewhite]

A quick test is to multiply the NA of an objective by 1000...

how to determine the 'NA' of the objective if the lens barrel lacks the data...?

the American Optical One-Fifty has four lenses, presumably 4, 10, 45 and the oil immersion 100...

thanks again...

[75RR]

how to determine the 'NA' of the objective if the lens barrel lacks the data...?

All objectives should have that data

presumably 4, 10, 45 and the oil immersion 100...

Presumably? I imagine by that statement that you have not purchased it yet, nor have you managed to have a good look at it. May I suggest that you wait until you have had a chance to use the microscope (whichever one you end up with) before purchasing or even considering upgrades.
It could save you money.

[apochronaut]

The American Optical 150 was a standard workhorse kind of microscope built for upper educational facilities and small labs. It is usually fitted with basic achromats ; a 4x .12, 10x .25, 45x .66 and a 100x 1.25 oil immersion, all with an infinity mark on the barrels. Any other AO, Reichert or Leica branded short tube( 34mm or less) objectives with the infinity mark on them will also work well.

The 15x eyepieces cat.# 184( that will be clearly marked on the barrel) eyepieces can also be used on this microscope . The image sharpness will be slightly less with the 4x,10x and 45x objectives but will be sufficiently well resolved to be entirely useful. This will not be the case with the 100x objective, with which the 15x eyepieces are not a suitable match.

Despite this microscope having the capacity to use the same optics, as the higher end AO microscopes, it has the limiting factor of having a relatively low illuminator output. Using the 15x eyepieces will lower the intensity of the illumination. This will be very noticeable with the 100x objective, so that, plus the lowered resolution when the 100x is coupled to the 15x eyepieces, further limits the 15x use to the 3 lo power objectives only.

[stonewhite]

hello

to go one step further with my inquiry, if I were determined to 'improve' the scope, would it be worth my while to look for objectives having more robust optics--for example, a 4x made by Leitz, Bausch and Lomb, etc.?

by the way, what do the initials 'NA' refer to...? you had mentioned at another thread that one might determine a lens' capability by a ratio between the NA and power, i.e., multiply the NA by 1000, then divide the power into that figure--a higher quotient being an index to that lens' capability...

if, then, I might locate a 4x with a higher NA, wouldn't I do well to install in the One-Fifty (all else being equal)...?

thanks again...

[75RR]

by the way, what do the initials 'NA' refer to...?

https://encrypted.google.com/search?q=na+microscopy

[apochronaut]

Stonewhite, here is the complete answer you were looking for , regarding objectives for your 150.

viewtopic.php?f=5&t=5073&p=46063#p46063