Questions about Wild Heerbrugg M11 microscope eyepieces and light source

[tomecki]

Hi,

I'm into mycology and mushroom identification and have been using a kid's microscope for the last couple of years. Another member of a club I belong to recently gave me a great little microscope that was salvaged from a university lab. It's a Wild Heerbrugg M11. There are a couple of things that I need to do to get it up to snuff though. The light source is missing and I need to add an eyepiece with a measurement reticle. I'm looking for some advice and have A LOT of questions. Hope someone here is patient enough to read this and help a newbie out

The scope came with two sets of Huygens (23mm) eyepieces: 6x and 10x. I should mention that the binocular adapter has an additional 1.5x magnification, and the objectives are the standard 4/10/40/100. I don't believe it's possible to add a reticle to a Huygens objective. I can't find any Wild eyepieces that would work for me, so I'm going to have to go with another brand. Can I just get any eyepiece of the right diameter? The originals have a very small opening, narrow field of view and low eye point. Will I see benefits from WF, super WF and/or high eye point eyepieces? Will ones with a long offset work? I've read that the eyepieces are often matched to the objectives (although my objectives are simple achromats) is any one particular brand going to be better matched? How do i know if it's possible to add a reticle to an objective I get online? From what I see, 6x is rare, so should I go with 5x or 10x?

As far as the light source goes, I'm going to either buy an illuminator from retrodiode.com or try to make one myself. If I go the DIY route, I'm wondering what the qualities of a good light source are. Does the beam have to be parallel? Should the glass in front of the LED be frosted? Any other considerations?

Thanks for your help in advance!

[MichaelG.]

Welcome, tomecki

The M11 is a great little microscope ... I recently purchased one myself, so we may be on a parallel learning path.

You may find this useful: http://www.science-info.net/docs/wild/m11-catalog.pdf
... and there is more Wild stuff in the parent directory: http://www.science-info.net/docs/wild/

MichaelG.
.
Edit: Oops ... forgot to mention this one http://www.microscopy-uk.org.uk/mag/art ... d-m11.html

[Hobbyst46]

Welcome tomecki.

I am using a LED lamp from RetroDiode.com with my (relatively) small microscope for more than a year by now. So I gained experience - mostly positive. I will gladly provide details, if you are interested.

Also, if you consider doing photomicrography, then I believe that, if you purchase a camera that is fully remote-controlled by software, it might perhaps save you the search for reticles. Only an inexpensive (20-30 USD or less on eBay) stage micrometer will be required for calibration.

[apochronaut]

Hi,

I'm into mycology and mushroom identification and have been using a kid's microscope for the last couple of years. Another member of a club I belong to recently gave me a great little microscope that was salvaged from a university lab. It's a Wild Heerbrugg M11. There are a couple of things that I need to do to get it up to snuff though. The light source is missing and I need to add an eyepiece with a measurement reticle. I'm looking for some advice and have A LOT of questions. Hope someone here is patient enough to read this and help a newbie out

The scope came with two sets of Huygens (23mm) eyepieces: 6x and 10x. I should mention that the binocular adapter has an additional 1.5x magnification, and the objectives are the standard 4/10/40/100. I don't believe it's possible to add a reticle to a Huygens objective. I can't find any Wild eyepieces that would work for me, so I'm going to have to go with another brand. Can I just get any eyepiece of the right diameter? The originals have a very small opening, narrow field of view and low eye point. Will I see benefits from WF, super WF and/or high eye point eyepieces? Will ones with a long offset work? I've read that the eyepieces are often matched to the objectives (although my objectives are simple achromats) is any one particular brand going to be better matched? How do i know if it's possible to add a reticle to an objective I get online? From what I see, 6x is rare, so should I go with 5x or 10x?

As far as the light source goes, I'm going to either buy an illuminator from retrodiode.com or try to make one myself. If I go the DIY route, I'm wondering what the qualities of a good light source are. Does the beam have to be parallel? Should the glass in front of the LED be frosted? Any other considerations?

Thanks for your help in advance!

The reason some mfg. optioned for 6X, is that it allows for a considerably wider f.o.v. than 5X but 10X has become the default standard , for many reasons, not all of them good. There is no doubt that your 6X seem inadequate by today's standards but in mycology , a broad range of magnifications is useful. 6X , usually have pretty good eye relief and you may find the 4x objective and 6X eyepieces quite useful for a look at some of the larger structures, especially when used with incident lighting, despite the narrow f.o.v.
Going to the other extreme in magnification, 10X eyepieces are limiting your higher end magnification. You are essentially wasting 250x extra potential magnification, magnification you could dearly use with some spores. I would hold out for a set of 12.5X. W.F. The offset , is that you will raise your magnification with the 4 and 10X objectives a little, maybe too much in some cases but you always have the 6X and your old 10X Huygens, to fall back on.
Compatability. From my experience, I see that WILD has some unique corrections. I would be very careful buying non-WILD eyepieces, until you learn more about their potential compatability with other types. Once you move away from Huygens or Ramsden, there is too much in proprietary corrections with most mfg. , to risk losing a portion of your wider field to lousy peripheral imaging. You may end up finding that a matched set of Huygens is superior.

I have some WILD stuff here. I can do a bit of testing for you and report back. At least that may put you on a better footing to start.

[mnmyco]

Hi,

I actually am a mycologist. I would strongly recommend buying a objective that is around 50x to 70x. On a Leica DM2500 (if I recall correctly) I was most found of the 63x objective. It provided a much better image of spores than the 40x and still did not need oil.

You can use reticles in Huygens eyepieces, but the reticle will have to be placed between the lenses.

[...]
Also, if you consider doing photomicrography, then I believe that, if you purchase a camera that is fully remote-controlled by software, it might perhaps save you the search for reticles. Only an inexpensive (20-30 USD or less on eBay) stage micrometer will be required for calibration.

How would that work? The focusing planes are never the going to be the same as the stage micrometer and so wouldn't your calculations be off? Or, would any difference be so small that it would not matter? I am not sure, but just curious as some fungi may be separated on the basis of less than a micron in average spore size.

mnmyco

[apochronaut]

There are specific measuring eyepieces with a built in focuser to adjust the focus on the reticle to match individual eyes. They came as huygens types and some were designed with high eye relief.

If you just want to measure infrequently, you can use one as a swap for either your left or right eyepiece at that point. Some install two, focused at the same point and leave them there; one with a reticle, when measuring is very frequent.

[MichaelG.]

Hi,

[...]
Also, if you consider doing photomicrography, then I believe that, if you purchase a camera that is fully remote-controlled by software, it might perhaps save you the search for reticles. Only an inexpensive (20-30 USD or less on eBay) stage micrometer will be required for calibration.

How would that work? The focusing planes are never the going to be the same as the stage micrometer and so wouldn't your calculations be off?

A stage micrometer is used to calibrate the eyepiece reticle [or the screen, or the camera]

MichaelG.
.
.
Edit: These are probably worth a look
https://m.youtube.com/watch?v=8TIyj8OrtWA
https://m.youtube.com/watch?v=qRLJapH3Gfg

[Hobbyst46]

[...]
Also, if you consider doing photomicrography, then I believe that, if you purchase a camera that is fully remote-controlled by software, it might perhaps save you the search for reticles. Only an inexpensive (20-30 USD or less on eBay) stage micrometer will be required for calibration.

How would that work? The focusing planes are never the going to be the same as the stage micrometer and so wouldn't your calculations be off? Or, would any difference be so small that it would not matter? I am not sure, but just curious as some fungi may be separated on the basis of less than a micron in average spore size.
mnmyco

Stage micrometers are used to calibrate eyepiece reticles, as MichaelG said. The stage micrometer is actually a standard slide, although without a coverslip. So a focused view of the micrometer scale marks provides the actual width of the field of view, in length units (um, say). For simplicity, assume a given eyepiece, switching only the objectives. Then, the width of the FOV is inversely proportional to the magnification of the objective. If the FOV for a 10X objective is 2000um, it will be 800um for a 25X objective, etc. On my decent microscope, this rule works fairly well between 6.3X and 100X objectives.

An appropriate camera control software (sorry that I have no experience with any such), coupled with an image analysis software (even freeware) can calculate the size/pixel ratio for each FOV, and provide the true sizes of objects, say the spores. One selects the spores and gets an immediate calculated average size. Or the software automatically selects the spores, according to predefined features. If the species identification is based on average spore size, sometimes statistics may be important, i.e. standard deviations, etc. The software does it easily.

I cannot guarantee, though, that the above calibration is accurate enough for your purpose. Sorry, having no mycology background, I apologize if what I suggested is impractical or irrelevant.

[MichaelG.]

Hello again, tomecki

Regarding the light source ...
Although I have the Koehler illuminator for my M11, I tried one of these this evening:
https://www.ebay.co.uk/itm/USB-LED-Nigh ... 2835053408

Very effective with low and medium power objectives: Highly recommended.

Note: The diameter is just under that of the hole in the M11 base

MichaelG.

[tomecki]

Hello again, tomecki

Regarding the light source ...
Although I have the Koehler illuminator for my M11, I tried one of these this evening:
https://www.ebay.co.uk/itm/USB-LED-Nigh ... 2835053408

Very effective with low and medium power objectives: Highly recommended.

Note: The diameter is just under that of the hole in the M11 base

MichaelG.

Thanks for the links and the suggestion on the light. I've been thinking about getting a light from retrodiode. They're a bit pricey, but I hear good things about them. I've been experimenting with different improvised light sources and I really think I'll need something bright and dimmable to get the most out of the microscope. I've been in contact with the retrodiode guy and he's coming up with a new design just for the M11. It's quite a bit more compact than the one he sells now. I might try the light you suggested in the meantime. Nothing to lose for that price.

[MichaelG.]

I might try the light you suggested in the meantime. Nothing to lose for that price.

Exactly !
... If nothing else, I think it will be ideal for travel use.

MichaelG.

[Hobbyst46]

Hello Tomecki,
Note that the LED source from RetroDiode has been dimmed with a PWM. PWM is less suitable than a constant current power supply. PWM may cause dark bands in photo images. So if you plan to do photography, I suggest to inquire about their 21KHz PWM, it is better than the basic PWM. Also, note that their cool light LED contains a very strong blue band.

[tomecki]

Hello Tomecki,
Note that the LED source from RetroDiode has been dimmed with a PWM. PWM is less suitable than a constant current power supply. PWM may cause dark bands in photo images. So if you plan to do photography, I suggest to inquire about their 21KHz PWM, it is better than the basic PWM. Also, note that their cool light LED contains a very strong blue band.

Thanks, good to know about the PWM.

What's the significance of the blue band in the cool light LED? Is it just the colour cast, or are there other drawbacks. Would you recommend the warm light instead?

[Hobbyst46]

Hello Tomecki,
Note that the LED source from RetroDiode has been dimmed with a PWM. PWM is less suitable than a constant current power supply. PWM may cause dark bands in photo images. So if you plan to do photography, I suggest to inquire about their 21KHz PWM, it is better than the basic PWM. Also, note that their cool light LED contains a very strong blue band.

Thanks, good to know about the PWM.

What's the significance of the blue band in the cool light LED? Is it just the colour cast, or are there other drawbacks. Would you recommend the warm light instead?

The blue cast is strong, but that is a matter of personal taste. It shows up in photos much more than what in eye view. I personally prefer to use a KR12 warming filter. On the other hand, one can use a short-pass filter, that blocks all "warm" light above 460nm (say), to extract just the blue light and gain some resolution (due to the short wavelength).

Please have a look at this previous thread: viewtopic.php?f=9&t=5686 where MichaelG and I discussed 'White' LEDs.

I have not tried warm white from RetroDiode, firstly because at that time it was only available by special order, secondly because I was not sure that it will be adequately intense; but several experienced members of this forum are using warm LED lights (mostly DIY I guess) and apparently like them.