Springtails and other soil mesofauna - Microscope reccomendations

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gvbox
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Springtails and other soil mesofauna - Microscope reccomendations

#1 Post by gvbox » Sun Dec 05, 2021 2:56 am

Hello! I'm a total beginner to microscopy, outside of some college biology labs. A major interest of mine is photographing collembola and other sub-mm soil fauna (at frankly terrible resolutions, my macro setup isn't ideal for anything much smaller than a bee), but I've really been wanting to start collecting slides and really being able to properly ID them under a microscope. Been poking my head around various microscopy boards, but I've been struggling between the bombardment of astroturfed websites just shilling for top sellers on Amazon and inconsistent reviews for the cheap brands like OMAX. I'm in a bit of an interesting situation here, as I don't necessarily want the *most* magnification -- lower-power microscopes seem to be better for imaging things on the 0.1-2mm scale, rather than in the micron range (amphipods, isopods, ostracods, collembola, mites, etc).

My budget is about $500, plus or minus 100. A trinocular that you can mount a DSLR on would be ideal. Darkfield microscopy looks appealing, also, so any that have relatively inexpensive filters for that would be nice! I'm really totally clueless here so I might need a bit of hand-holding. No idea what brands and such are standard outside of the big $8k Nikon microscopes.

Thank you for any help you can provide, and I really look forward to chatting with all of you! :D

don1357
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#2 Post by don1357 » Sun Dec 05, 2021 4:21 am

Well here is the blind leading the blind... I'm sure I'll be corrected if I misspeak.
  • Magnification is the easiest thing to fake so most vendors love to tout x2000+ which means nothing. Think of magnification as the ability to zoom into a small web image: you can see it bigger but it just gets blurrier and blurrier. That's because what magnification doesn't do is improve the resolution. It is better to have a lower power that produces a higher quality imaging.
  • As I'm sure you know multiplying the power of the objective by the power of the eyepiece gives you the total magnification. The second number you want to look at is the Numerical Aperture (NA) of the objective which tells you how much you can multiply the objective power before resolution suffers. for instance a 100x objective rated 100x/0.85 will let you magnify to x850 power without loss of image quality. This is where said objective matches well with a 8.5x eyepiece. As you can see a 25x eyepiece will far exceed the ability of any basic objective to create a sharp image.
  • objectives north of 1.00NA like the standard 100x/1.25 are wet objectives, meaning they need a drop of oil to work properly. That is because the refraction of air is 1.00, so you need a medium between your sample and the objective in order for the light to travel without diffraction. https://www.leica-microsystems.com/scie ... esolution/
  • The threshold for an entry level microscope starts with a mechanical stage; the ability to lock the slide and move it around with the fine control knobs. Anything that doesn't have a mechanical stage is at best a toy.

TonyT
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#3 Post by TonyT » Sun Dec 05, 2021 6:36 pm

A low power dissecting scope is needed for sorting specimens; a cheap American Optical works fine.
For photography you do not need a microscope
use Nikon CFN objectives on bellows or extension tubes; a 20x will magnify a 1 mm springtail enough to fill the frame of most cameras.
a 10x and 40x are also useful.
http://www.microscopy-uk.org.uk/mag/art ... garden.pdf
New Brunswick
Canada

don1357
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#4 Post by don1357 » Sun Dec 05, 2021 7:18 pm

One of the best lenses ever created was the Vivitar Series 1 90 mm f/2.5 VMC Macro. The sharpness and flatness of field is amazing. It can do 2:1 by itself and 1:1 with the included extension. If you get one do make sure it comes with the original extension tube; unlike a plain tubes it has optics that were optimized for this particular lens.

Chas
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#5 Post by Chas » Mon Dec 06, 2021 9:53 am

You havent mentioned what you already have, camera-wise.... DSLR or something else, a macro lens .. reversed lens?
Bridge camera, mobile phone?

gvbox
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#6 Post by gvbox » Tue Dec 07, 2021 7:40 am

Chas wrote:
Mon Dec 06, 2021 9:53 am
You havent mentioned what you already have, camera-wise.... DSLR or something else, a macro lens .. reversed lens?
Bridge camera, mobile phone?
A DSLR, but not a great one. Nikon D3300, with two lenses I can use for macro (Sigma 105mm f/2.8, and the stock 18-55mm with macro extenders). Doing the math the maximum magnification I'm able to get with what I have is 2:1.

Chas
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#7 Post by Chas » Tue Dec 07, 2021 5:31 pm

Cool. To help you get your bearings:
What you think of as 1:1 Macro would equate to 10x magnification in microscope-speak (created by, say, a 1x objective and a 10x eyepiece) this is an 'order of magnitude' approximation
Again, in order of magnitudes, the chinese DSLR eyepiece-adapters behave like ~10x eyepieces.
So to achieve roughly 4:1 you are looking at using a 4x objective.
Objectives often come in a 4x 10x and 40x sequence.

Microscope objectives have no aperture control to help you with the depth of field and this decreases as the magnification of the objective increases, so you will very likely end up focus-stacking.

On a very basic level the objectives come in two primary types; 160mm tube-length and 'infinite'.. the latter need an extra lens between the objective and the eyepiece, but this is the most modern system.

I cannot advise which way to go as I haven't the years of broad comparative experience that others have. But I went along the line of getting an old (1943) horshoe-stand monocular microscope and gave it some modern Nikon CFI objectives as these are coated and are also known to work as good macro lenses in their own right.
To take photos, I pull out the microscopes' eyepiece and put in the DSLR eyepiece-adapter with the camera attached and take the stack.. using a cable release.... I feel that it works well enough, for the 4x and the 10x objectives but the 40x objective is quite picky about tube-length.
There are a couple of kinds of eyepiece adapter; one that contains lenses and one that is an empty tube ..I use both, but mostly the empty tube one .. the (more expensive) lensed adapter is a bit of a dust magnet and the dust is pretty visible in the final stacked images.
In a sense you are using the microscope body as a fixed length extension tube*.

There is also something that might be worth thinking about .. a lot of insects can be transiently aneasthetised with gas and when they wake up they are somewhat bewildered .. which is another opportunity to get a living photo. Surrounding the insects with half a ping-pong ball [which works as a light diffuser], as they wake up, makes them more bewildered I think.

* You can use 160mm tube-length microscope objectives on a shorter tube and get a lower magnification by using something like this cone adapter, which has an RMS objective thread in its nose and a standard thread on the back, then add a converter to get to your Nikon mount :
RMS cone adapter.jpg
RMS cone adapter.jpg (25.55 KiB) Viewed 3958 times
With a 4x objective this will get you back to your exisiting 2:1 ... Its very lightwight, though, and your camera's pop-up flash will probably shoot over the top of it :-)

Maybe it is worth mentioning that there are glass microscope slides that have a raised ring mounted on them, small creatures can be tipped into the middle and a cover slip put on top :
slide.jpg
slide.jpg (105.82 KiB) Viewed 3958 times
And when they wake up you can watch/photograph them.... they always seem to manage to escape in the end though.it might work for your springtails.

BramHuntingNematodes
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#8 Post by BramHuntingNematodes » Thu Dec 09, 2021 6:25 am

I nabbed some springtails the other day while looking for...stuff. They were the right size and I finally made a successful mount using euparal. Two in fact (the third, right into the trash)! The specimen is not stained, but is naturally this blue-indigo. Anyways, these were taken through an eyepiece on the trusty 1942 Dynoptic (a year older than Chas's venerable old stand even). Non-plan apos roughly contemporaneous with the scope. Some post-processing might have helped, but these are "off-the-saw" as it were.

Image
Using non-contemporaneous WF-22 eyepieces, the lens is not plan and you can tell its powers are being stretched to the breaking point.

Image
I think we had one other person looking out for Dynoptic bits: the 20x is the best.

Image
The furcula. Oh that 20x, something to swoon over.

Image
It's hard to get a great image in brightfield using this ancient 47.5x perhaps because the AR coatings are either not there or limited. Lot of glare, and if you tamp down the iris you get problems but not much improvement.

So there you have it. Springtails can be imaged pretty well using old equipment.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Chas
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#9 Post by Chas » Fri Dec 10, 2021 12:15 pm

Nice..
I should perhaps have mentioned that now that I have the original objectives clean, they are back on the microscope:-)
The benefit of the Nikon objectives and their coating/design shows up when the lighting is primarily coming from the sides (for example, when photographing something opaque...a butterfly wing )
The important design difference might be something as simple as the Nikon 4x having a shroud over its nose.
I dont see a lot of benefit using the coated 4x and 10x, with transmitted light.
[Along the way I did get some new coated no-name Chinese Plan objectives.. I cannot get on with them at all..very vibrant chromatic error colours .. not as kind on the eye as the orginal objectives].
TBH I also enjoy taking relected light pics with older non-coated lenses and having a little bit of soft haze :-)

BramHuntingNematodes
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#10 Post by BramHuntingNematodes » Sat Dec 11, 2021 2:20 am

Ah yes, may have undersold that 47.5x as it is one of my all-time favorite lenses. Here it is after adjusting the collar a bit and cleaning some surfaces:
Image

The coating issue really only shows up for this lens as the immersion has that homogeneous medium thing going on and the lower lenses don't need as intensely focused light. No doubt the high-dry are the most challenging of my lenses to use.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Chas
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#11 Post by Chas » Sat Dec 11, 2021 8:01 pm

That is quite an improvement, not that the other was poor!
I got out the new Chinese plan lenses,I mentioned, which had vibrant chromatics .. (green edges when focused above, red focused below) ... the 40x Plan was actually rather clearer than the 40x Watson Parachromatic on my newer Watson Service II :-(
-A lot of lens cleaning ensued .. and I now have the Watsonx40 just about matching the Plan for clarity. ... and the plan's chromatic colours that I imagined would add up to something horrible in a focus-stack, were not particularly visible in an end result.
I have learnt, amongst other things, that cleaning up old objectives requires rather more dedication than I .....
:-)
Last edited by Chas on Mon Dec 13, 2021 12:51 am, edited 1 time in total.

Chas
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#12 Post by Chas » Sun Dec 12, 2021 3:27 pm

Maybe the point is that any old microscope is better than none ;-)
Here is a cropped pic of a parasitoid inside a thunderflies head.. taken by resting the DSLR camera body on top of a Baker monocular and using the 2/3 Inch objective:
Para in thunderfly head 1024.jpg
Para in thunderfly head 1024.jpg (57.31 KiB) Viewed 3733 times
Without a microscope you wouldnt get to see such things (or imagine them, as I may just have done!).

I think it is real: 3D courtesy of Zerene and SPM, it seems to have partly emerged from the head :-)
2021-12-12-19.10.43 ZS stereo_000 1024 sized.jpg
2021-12-12-19.10.43 ZS stereo_000 1024 sized.jpg (86.97 KiB) Viewed 3670 times
Last edited by Chas on Mon Dec 13, 2021 7:39 pm, edited 1 time in total.

BramHuntingNematodes
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#13 Post by BramHuntingNematodes » Sun Dec 12, 2021 4:41 pm

Remarkable! Such a minimal setup goes to show.that practical experience is the most important component.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

einman
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Re: Springtails and other soil mesofauna - Microscope reccomendations

#14 Post by einman » Mon Dec 13, 2021 5:25 pm

I raised collembola for several years to feed my dacetines. Interesting creatures.

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