Please help a microscope noob with objectives

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
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Aaron
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Please help a microscope noob with objectives

#1 Post by Aaron » Tue Jul 07, 2020 4:13 pm

All,

I'm in the process of building an arduino/raspberry pi based microscope. I've gathered most of the parts. I'm down to the objectives. The build instructions call for 160mm tube and 45mm parfocal. I'd like to get an assortment, say 10x 40x and 100x (give or take). I've been looking on E$ay and there, of course, a lot listed but the sellers rarely include the specs. I'm hoping you can steer me in the right direction. I'd like to get decent lenses that won't break the bank and aren't who-knows-what Chinese. There's a couple listings for B&L lenses but I struggle to verify the specs match what I need. I've read a few old catalogs online but many don't state parfocal. I'm guessing that after a certain year 45mm became standard, but I don't want to assume. Any any rate, after much Googling this forum kept coming up. So, you guys drew short straw. Sorry about your luck. ;)

I imagine you all are familiar with it but here's the scope project that I am working on. https://openflexure.org/projects/microscope/

Thanks in advance,
Aaron

Zuul
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Re: Please help a microscope noob with objectives

#2 Post by Zuul » Tue Jul 07, 2020 4:58 pm

I am very curious what the point of this project is? The objectives are the expensive part of a microscope. A good quality older stand can be purchased for less (maybe far less) than the materials needed to print the microscope in your link. The illumination design alone will be extremely limiting ... I doubt a 100x objective would be usable, but even if it is, resolution will be poor.

To answer you question directly; Chinese objectives are not going to limit the performance of this microscope. (They are decent, if not great, quality optics.) Spending more probably won't make a noticeable difference. In the used market, knowing which objectives will work for you does require more than a little research. Objectives for 160mm tube length are easy to identify because it will be printed on the barrel (160/.17 for example). To be certain of the parfocal distance, it would be easier to link specific objectives so the experts can identify them for you.

BramHuntingNematodes
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Re: Please help a microscope noob with objectives

#3 Post by BramHuntingNematodes » Tue Jul 07, 2020 5:01 pm

Yeah you should be able to get a whole set of old B&L achromat lenses pretty cheap they are 160mm tube length but 35 and 2/3mm parfocal length. Think you can move the stage up 9mm?
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
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Re: Please help a microscope noob with objectives

#4 Post by BramHuntingNematodes » Tue Jul 07, 2020 5:04 pm

Also to echo Zuul's sentiments, if this project is just for your personal enthusiasm for 3D printing go for it, but the end result will undoubtedly be a much inferior product to an old cast iron and machined brass microscope stand made by and for professionals that could be had for $50 or less.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

apochronaut
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Re: Please help a microscope noob with objectives

#5 Post by apochronaut » Tue Jul 07, 2020 5:25 pm

Did you not get the lego set you wanted when you were 4 or something?

MicroBob
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Re: Please help a microscope noob with objectives

#6 Post by MicroBob » Tue Jul 07, 2020 6:52 pm

Hi Aaron,
I think the combination of computer and optics has lots of future. Especially in the form of an open source project where many people contribute to the further development.

Most 160mm objectives are calculated with a residual chromatic error that is corrected by the eyepiece. So if your camera sits with its own objective on an eyepiece the eyepiece would have to match the objectives. For older systems different eyepieces were used for different objectives. Later systems beginning I think with the Zeiss Standard had objectives that were calculated to have all the same chromatic error.

100:1 objectives are usually calculated as oil immersion objectives - are you prepared to use oil?

For magnifications above 100x you will need a condenser to provide the right illumination.

As a second step it might be an advatage to switch over the electronics to a real microscope stand as the plastic components will be the bottle neck of the system. So you might just buy a complete microscope to get a matching set of components.

Bob

Zuul
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Re: Please help a microscope noob with objectives

#7 Post by Zuul » Tue Jul 07, 2020 8:24 pm

MicroBob wrote:
Tue Jul 07, 2020 6:52 pm
Hi Aaron,
I think the combination of computer and optics has lots of future. Especially in the form of an open source project where many people contribute to the further development.

Most 160mm objectives are calculated with a residual chromatic error that is corrected by the eyepiece. So if your camera sits with its own objective on an eyepiece the eyepiece would have to match the objectives. For older systems different eyepieces were used for different objectives. Later systems beginning I think with the Zeiss Standard had objectives that were calculated to have all the same chromatic error.

100:1 objectives are usually calculated as oil immersion objectives - are you prepared to use oil?

For magnifications above 100x you will need a condenser to provide the right illumination.

As a second step it might be an advatage to switch over the electronics to a real microscope stand as the plastic components will be the bottle neck of the system. So you might just buy a complete microscope to get a matching set of components.

Bob
The scope he is talking about is camera only; no eyepieces. Are there fully corrected 160mm objectives?

It also an inverted design, so oil is a no go. The "condenser" is not an optically designed component; just a 5mm led behind a makeshift lens.

Scarodactyl
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Re: Please help a microscope noob with objectives

#8 Post by Scarodactyl » Tue Jul 07, 2020 8:26 pm

Zuul wrote:
Tue Jul 07, 2020 8:24 pm
The scope he is talking about is camera only; no eyepieces. Are there fully corrected 160mm objectives?
Of course--the nikon CF series, and some modern Chinese copies.

Zuul
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Re: Please help a microscope noob with objectives

#9 Post by Zuul » Tue Jul 07, 2020 10:49 pm

Scarodactyl wrote:
Tue Jul 07, 2020 8:26 pm
Of course--the nikon CF series, and some modern Chinese copies.
Then Chinese are as good as anything. Putting Nikon glass on this project would be ... unnecessary. :shock:

Aaron
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Re: Please help a microscope noob with objectives

#10 Post by Aaron » Tue Jul 07, 2020 11:07 pm

Certainly I could buy multiple quality scopes on the used market for the investment. The project is the point. It's an opportunity to incorporate an arduino and a raspberry pi. It involves sourcing a custom pcb (something I haven't done before), buying the electronic components, building the board, and programming. In short, it looked like something interesting to mess around with and see what comes of it. Going into it I was fully aware that not all experiments end in success.

The main reason I shy away from the Chinese stuff is the unknowns. Are you really getting what they say you are? Is the quality good (enough)? Of course, the same could be said about buying used lenses. I really expected it to be easier to look up the specs of a given lens and know exactly what it is, but it's proving more difficult than anticipated. I thought that the information would be more readily available than it is.

Scarodactyl
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Re: Please help a microscope noob with objectives

#11 Post by Scarodactyl » Tue Jul 07, 2020 11:55 pm

Zuul wrote:
Tue Jul 07, 2020 10:49 pm
Putting Nikon glass on this project would be ... unnecessary. :shock:
I am not sure what you mean by this.

Nikon cf objectives are often available inexpensively, and even the lowest-tier 'e' economical line are pretty good.

Zuul
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Re: Please help a microscope noob with objectives

#12 Post by Zuul » Wed Jul 08, 2020 12:07 am

Aaron wrote:
Tue Jul 07, 2020 11:07 pm
The main reason I shy away from the Chinese stuff is the unknowns. Are you really getting what they say you are? Is the quality good (enough)? Of course, the same could be said about buying used lenses. I really expected it to be easier to look up the specs of a given lens and know exactly what it is, but it's proving more difficult than anticipated. I thought that the information would be more readily available than it is.
With Chinese objectives you will get what you expect and it will be of reasonably good quality. To be certain, buy from a reputable source like AmScope and you will have nothing to worry about. You can get better objectives for less money, but not ones that meet your specified requirements. (based on the suggestion above that Nikon was going to be the only real option)

The biggest complaints I've heard about reputably sourced chinese objectives is they can be pretty hit or miss in terms of being parcentric and parfocal. That's is of zero concern for you because you won't be switching back and forth on the scope you are building ... it being a single lens design.

Don't bother with a 100x objective, though. That design won't be able to use it to any degree of it's capacity. Pond life and similar subjects are easily observed at much lower powers, anyway. 20x is very popular.

Zuul
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Re: Please help a microscope noob with objectives

#13 Post by Zuul » Wed Jul 08, 2020 12:14 am

Scarodactyl wrote:
Tue Jul 07, 2020 11:55 pm
Zuul wrote:
Tue Jul 07, 2020 10:49 pm
Putting Nikon glass on this project would be ... unnecessary. :shock:
I am not sure what you mean by this.

Nikon cf objectives are often available inexpensively, and even the lowest-tier 'e' economical line are pretty good.
What I meant is, the scope design has very rudimentary lighting, so trying to eek out the last bit of optical quality isn't likely to be money well spent. I have not really paid attention to used pricing on Nikon objectives, so I may be wrong, but wouldn't those still be considerably more expensive than a typical Chinese achro?

BramHuntingNematodes
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Re: Please help a microscope noob with objectives

#14 Post by BramHuntingNematodes » Wed Jul 08, 2020 1:18 am

I got a raspberry pi on the old dynazoom right now. It runs the camera and some software. Very useful for adjusting all the camera settings and capturing images. Probably could hook up some stepper motors here and there to dials and knobs and get an automated scope. I hear there are some neat techniques that can combine a lot of conventional images to make dimensional maps of objects. Might be neat someday.

Anyway, the real stands have enormous advantages in terms of positionability, rigidity and mass. I don't have a 3d printer but have made several small adapters, jigs, manipulators and other apparatus out of wood. 3d printing could definitely have a place in a mnovel project, but a plastic stand just seems like maybe the worst application for the technology? I don't know.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Scarodactyl
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Re: Please help a microscope noob with objectives

#15 Post by Scarodactyl » Wed Jul 08, 2020 1:26 am

A used low end objectivd in the CF series is probably around 30-40 bucks. Not as cheap as the cheapest Chinese options which may be just as good (but with less certainty on level of corrections).
I'll look forward to seeing results from this. 3d printers are tremendously useful in microacopy for things like making adapters, but a whole stand ought to be interesting.

Bogdan
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Re: Please help a microscope noob with objectives

#16 Post by Bogdan » Thu Oct 15, 2020 9:31 pm

I built this scope and it’s beautiful.
The image is as good as the objective is, the flattest the better.
This is an extraordinary project if you think you get a completely robotized microscope with slide scanning capability that can be operated remotely from any corner of the world.
Resolution with a chinese objective is good enough to see ciliary rows on spirostomum which is good enough for me and also good enough to detect malaria in prepared blood samples in poor or remote places in the world.
The stage has at least micron level movement, even if the movement range is much smaller that the one of a normal microscope.
Also, with proper filters (which I couldn’t get in covid times) you have possibility to add epi fluorescence to it.
Another point is the software which is open source and under development so othe modules can be added along with what has been implemented yet.

You need to think about all these advantages before judging and how much would a scope with these capablites but maybe better optics would cost and what level of support you need in order to repair it if it gets broken.

Scarodactyl
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Re: Please help a microscope noob with objectives

#17 Post by Scarodactyl » Thu Oct 15, 2020 9:35 pm

If you wouldn't mind I think starting a new thread with some pictures and info about this scope would be greatly appreciated. I'm sure I'm not the only one who has been curious!

Bogdan
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Re: Please help a microscope noob with objectives

#18 Post by Bogdan » Thu Oct 15, 2020 9:38 pm

I have information scattered all over the place, will try to put something together in the next days.
Forum firmat makes it difficult for me to add all the pictures an movies I have, will see what I can do.

MicroBob
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Re: Please help a microscope noob with objectives

#19 Post by MicroBob » Thu Oct 15, 2020 10:19 pm

Hi Bogdan,
pictures have to be max. 1024 pixel long side. Videos can't be uploaded here but you can post a link to an external video like on vimeo or youtube.

I see much future in projects like this so I would be happy to see how far you got so far.

Bob

Bogdan
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Re: Please help a microscope noob with objectives

#20 Post by Bogdan » Thu Oct 15, 2020 10:47 pm

I finished it but can’t modify some pictures on my phone to be able to attach to this post. :)

Bogdan
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Re: Please help a microscope noob with objectives

#21 Post by Bogdan » Thu Oct 15, 2020 11:05 pm

Managed to add a lot of picture from during the build into a google shared album.
Here’s the link, hope it works:

https://photos.app.goo.gl/qzybfqbpnze6oyDX8

BramHuntingNematodes
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Re: Please help a microscope noob with objectives

#22 Post by BramHuntingNematodes » Thu Oct 15, 2020 11:32 pm

Not bad now time to program it to follow the protists around
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

Bogdan
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Re: Please help a microscope noob with objectives

#23 Post by Bogdan » Thu Oct 15, 2020 11:35 pm

Wouldn’t that be great?
I think the feature is somewhere on developing team’s list so maybe will be implemented someday.

MicroBob
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Re: Please help a microscope noob with objectives

#24 Post by MicroBob » Fri Oct 16, 2020 12:12 am

On my android phone I use snapseed for image editing and sizing down. The suffix has to be jpg not jpeg in some forums. I will have a look at you google album!

MicroBob
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Re: Please help a microscope noob with objectives

#25 Post by MicroBob » Fri Oct 16, 2020 12:26 am

The microscope seems to be well designed and the results are good. For a microscopist the question would be: "What do I gain and loose by using a 3D-printed microscope over using a normal lab microscope as my basis?". A lab microscope for use in this project could be very cheap as expensive things like trinocular tubes and high quality eyepieces would be unnecessary. What I like is that the output doesn't depend on buying expensive additional hardware but on the further development of the software. Maybe a connection to ImageJ could be a good development direction as it already offers a lot of scientific image analysis tools

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