Help with microscope aquisition!

[Pine]

Greetings everyone!

I´m in search for a new microscope. I have two very old ones that are more museum pieces than operational equipment.

My primary objective will be cell (yeast) counting and viability analisys. Also, I´ll do some basic bacteria identification. Last but not less important, it will be used as a hobby and educational tool (curious five year old son here).

Cell counting could be done with almost any "cheap" chinese microscope like Amscope/Omax in U$300/400 range. Some of them already comes with cheap USB cameras that could be very useful to automate cell counting. But I´m not sure these cheap scopes can obtain images with enough quality for me to do bacterial morphological analysis.

I do not want to give an arm and a leg for a microscope, but expending some more money on something that gives you better quality, versatility and durability appers to be a great deal. My initial budget is around U$500 but it could be extended.

I saw several people recommending second hand big brand microscope instead of buy a new chinese one. Other poeple says modern lens will be vastly superior to glass from two or three decades ago because of evolution in lens construction.
I also saw good reviews/comments of some chinese models. Two very interesting threads on this topic: viewtopic.php?f=24&t=4701 and viewtopic.php?f=24&t=4243&start=30

I used Nikon, Olympus and Zeiss at University (I prefer Nikon but other brands are nice). I also used some no brand microscopes that are really too much inferior to the big brand ones. At least three decades ago it was my impression. Nowdays appears that cheap microscopes like Amscope/Omax/Celestron evoluted a little.
That puts me towards a big brand, maybe a used one. But the truth is I´m not very confortable with used microscopes. I do not have the expertise to repair or solve most of the problems. Even with that feeling I looked for some used brand microscopes locally and found an binocular Olympus CH20 for U$200,00 in the neighborhood. The owner said it needs some maintenance (change a coil in the slide holder) but beyond that it is in good working condition. I´ll check it "in situ".

I found a Nikon E100 for U$ 540 with 10x eypiece and 4/10/40/100x infinity plan Nikon objectives, but It has a crack at the plastic in one of the eyepices that worried me a lot.

A local dealer offered me a refurbished binocular Olympus CBA (anyone have experience with this model?) for U$ 460, but I think it is quite expensive for an simple old microscope.

Also found two binocular Zeiss but they are too far away to be "visited":

Zeiss 46 70 65 (KF10x eyepice - 3,2x, 10x, 40x and 100x oil objectives) and
Zeiss Standart (10x/18Br 3,2/0,07 10/0,22 40 /0,65 100/1,25) both are around U$400 but owners do not know much about microscopy and can´t even answer my questions.

A local Nikon distribuitor offered me a new Nikon E100 LED for U$1.200 with free shiping and local warranty. They usually go around U$1.500 in Brazil.

I really don't see much advantage in infinity optics. Maybe infinity lens have some advantage of modern manufacturing technologies... E100 have darkfield and phase contrast kits that are right in my area of interest as a hobbist, but they are really expensive tough.
I´m not sure what I can find for CH20.

I´ll be in California for the next month and maybe I can find some offer from a trusted seller in ebay or an attractive price on a refurbished brand microscope from a good microscope dealer.
Does anyone have any recommendations?


My other option is a new Amscope/Omax. I was thinking in Amscope T490 or T580 (mayabe a T690 because of the comments about it´s construction in thread cited above) with plan objectives and dark field. So I called Amscope representative and asked about the differences on T340/T410/T490/T580. Amazingly he told me that they are all the same with aesthetic differences. Only T430 is made with better optics!!! What????

At least T580 is a simul-focal trinocular head microscope and T400 have a 30W light.... but his answer made me think about what kind of equipment they are selling. Maybe Omax could be a better option.


After some time researching for my new aquisition, I have more questions than aswers:

Used big brand - vs. - new no big brand - vs - new big brand entry level?

Infinity - vs - 160 TL?

USB camera - vs. - cmount for DSLR?


Any help will be really appreciated.


Sorry for the long message and, please, excuse my poor English skills.



Best Regards,

Marcelo.

[75RR]

I´ll be in California for the next month and maybe I can find some offer from a trusted seller in ebay or an attractive price on a refurbished brand microscope from a good microscope dealer.
Does anyone have any recommendations?

This does sound like your best bet.
Can stateside members come up with something?

[zzffnn]

Marcelo,

What exact "bacterial morphological analysis" do you want to do with light microscope? If that really is your main goal, please explain it in detail and feel free to be technical. I should be able to understand it and help you (I have a PhD in Bacteriology).

For detailed bacterial morphological analysis, TEM is usually used. No light microscope is resolving enough.

I think phase contrast and darkfield will be your best bet. Also specific staining and/or surface antigen analysis.

If you are coming to US, get a used AO 10/20/110/120 equipped with phase and darkfield. American Optical Spencer is a high quality US brand that dos not cost much. It offers one of the best performance for phase contrast at low budget. The models I suggested are infinity corrected, so you can have to used AO infinity objectives (160 tube length objectives won't work).

I suggest a mirrorless camer, if you don't currently have any good camera. Or use a DSLR, if you already have one.

Which brand and infinity or not depends on your application, specific needs and luck/budget. I prefer 160 tube length and use big brands myself, because I want water immersion (which is too expensive from infinity objectives) and like to mix-and-match different brands of 160TL objectives (which is not as easy with infinity objectives).

[Hobbyst46]

Marcelo
For cell counting and viability tests, I think that direct operation (tethering) of the camera from a personal computer (laptop, desktop) is very benefical.
Mirrorless are advantageous relative to DSLRs and other cameras in some respects, but not all of them can be tethered.
Good luck.

[MichaelG.]

I prefer 160 tube length and use big brands myself, because I want water immersion (which is too expensive from infinity objectives)

My apologies for briefly hi-jacking the thread ... but could I please just ask zzffnn
Do you have any technical details for the Nikon 20x / 0.4 WI
If I understand correctly, this is classed as a 'Water dipping' objective
...hence the 160/- designation
Mine is marked 120143, but I don't know whether that is a Model or Serial Number

It's in the same series as this 40x version:
https://www.spachoptics.com/NIKON-40X-W ... -water.htm

Many thanks
MichaelG.

[apochronaut]

Marcelo,

What exact "bacterial morphological analysis" do you want to do with light microscope? If that really is your main goal, please explain it in detail and feel free to be technical. I should be able to understand it and help you (I have a PhD in Bacteriology).

For detailed bacterial morphological analysis, TEM is usually used. No light microscope is resolving enough.

I think phase contrast and darkfield will be your best bet. Also specific staining and/or surface antigen analysis.

If you are coming to US, get a used AO 10/20/110/120 equipped with phase and darkfield. American Optical Spencer is a high quality US brand that dos not cost much. It offers one of the best performance for phase contrast at low budget. The models I suggested are infinity corrected, so you can have to used AO infinity objectives (160 tube length objectives won't work).

A limited amount of morphology can be done on bacteria with light microscopes of sufficient quality but as Fan says, it is mostly done with TEM. Having information about the context of your sample can assist in deduction. Yeasts are a little easier. You must have fluorite or apochromat objectives , and it helps for them to be plan and of fairly modern design, in order to get any image quality whatsoever with bacteria. Phase, DF, DIC and oblique are a must. Staining can yield some features, if you have a comparative reference. Objectives designed from about the mid-1980's forward are usually needed. Chinese microscopes with achromat or planachromat objectives will be useless for such a task. Chinese optics in general, are less good than quality optics made in Germany,U.S.,Britain,Poland,Russia and Austria from even the 1970's. There are some planF objectives being made of o.k. quality and the only real quality option for such a task comes from Motic, who make planapos, I believe. They begin to be pricey. Well outside what one would expect from a Chinese scope.
I recently had samples of milk from a small dairy that is having intermittent very premature spoilage problems. A handful of bottles, in batches, from most recent production runs are developing a cheesy nose 10 or more days before the BBD. The milk will not foam, which usually is caused by a low protein content. There is no clabbering, so the milk looks normal.
Under BF and DF, using 100X 1.25 N.A planachromats from 1990's mfg.( AO/Reichert, U.S.A. and Austria mfg.), only a fleeting hint of some movement was evident, parting the butterfat globules, here and there. With phase, muddy shapes of a very motile bacillus of some kind could be discerned but aside from the behaviour, no morphology of note could be discerned. However, using a planfluor apo 100x 1.30 phase objective, captures with enough detail to get a fix on the species( spores, size and some inclusions) could be made. Combined with the behaviour ,context and protein destruction in the milk, B. Cereus seems the most likely culprit. It is a post pasteurization survivor, forms biofilms and hydrolizes casein. ....but most of that deduction was done using information other than bacterial morphology, however.

[JimT]

My suggestions;

Used big brand - vs. - new no big brand - vs - new big brand entry level?

If you can inspect a used big brand try that. Your first time should warn you as to what you might get.

"New no big brand" would be my choice unless you want to spend a fair bit of time finding and replacing bad used parts. BTW, Amscope and Omax are esentialy the same.

"New big brand entry level" - absolutely not.

Infinity - vs - 160 TL?

160 for sure. See this site:

http://www.microbehunter.com/should-i-b ... ed-optics/

USB camera - vs. - cmount for DSLR?

DSLR for sure. Sensor size, resolution, shutter speed, ISO, etc and if it is a Canon you can tether it to a computer with remote shooting.

Good luck.

JimT

[apochronaut]

Infinity - vs - 160 TL?

160 for sure. See this site:

http://www.microbehunter.com/should-i-b ... ed-optics/


JimT

The only problem is that some of that information isn't correct. There is more interchangeability than is indicated in that little chunk of info. and all of the optical refinements by the major manufacturers over the past at least 25 years in all cases, 40 years in another and almost 60 years in another have been in infinity correction. Without a doubt, all of the best optics in existence have been built for infinity systems. That isn't because infinity correction is inherently superior, it is because since about 1995, no one has been engineering the best microscope optics for fixed tube microscopes.
You can buy a 150.00 used microscope that is infinity corrected from at least 2 manufacturers right now and upgrade it with optics that were designed in 2010. You cannot improve fixed tube microscopes much beyond the state of the art that existed , at the time the company that made them abandoned the principle.

[75RR]

Any meaningful discussion comparing top of the range 160 objectives vs top of the range infinity objectives needs to take price into account.

Back to Pine's question:

Hope this article helps: http://www.microscopy-uk.org.uk/mag/art ... oscope.pdf

[PeteM]

If you're in the Bay Area of Northern California, our Children's Museum has 55 microscopes recently donated, which they are now selling. For around $500 there are Nikon Labophot, Olympus BH2, Reichert 410 etc. models in nice shape. There are also a couple of phase microscopes around that price.

PM me if interested in a "catalog" of what's still available. The Children's Museum won't ship, so you'd have to be in the area.

[apochronaut]

Any meaningful discussion comparing top of the range 160 objectives vs top of the range infinity objectives needs to take price into account.

Back to Pine's question:

Hope this article helps: http://www.microscopy-uk.org.uk/mag/art ... oscope.pdf

Yes, I do understand that high quality optics in 160mm tube format and 170mm format can be purchased for considerably less than many high quality optics in infinity format but that depends entirely on what you are buying. As previously mentioned , most of the quality manufacturers abandoned fixed tube optics anywhere from around 25 to almost 60 years ago. Some of those brands have a cult status and command high prices for reasons unconnected to their performance as a microscope, even for some relatively obsolete optics. If one is buying a microscope for the practical purpose of using it as a fine performing microscope, and since the time has long elapsed since when optics could be considered new school, the costs between the two can be quite equal, if not even cheaper for infinity optics, if one stays away from cult scopes. An additional bonus is the capability to build certain of the infinity systems in the future with more state of the art optics as they become available at acceptable prices on the used market.

[75RR]

An additional bonus is the capability to build certain of the infinity systems in the future with more state of the art optics as they become available at acceptable prices on the used market.

I look forward to that day!

[apochronaut]

An additional bonus is the capability to build certain of the infinity systems in the future with more state of the art optics as they become available at acceptable prices on the used market.

I look forward to that day!

Uhhhhh.... future as in future for current fortunate owners of an infinity system. so it is already here.
such as https://www.ebay.com/itm/Reichert-Plan- ... Swxrlaq4UB

[PeteM]

An additional bonus is the capability to build certain of the infinity systems in the future with more state of the art optics as they become available at acceptable prices on the used market.

I look forward to that day!

Uhhhhh.... future as in future for current fortunate owners of an infinity system. so it is already here.
such as https://www.ebay.com/itm/Reichert-Plan- ... Swxrlaq4UB

If the phase ring of that lens (Apo's listing above) matches up with those on a Reichert 410/420 microscope, it might be about as well as Pine could affordably do for a light microscope? The combination of a near mint 410 and that lens (along with the usual complement of infinity Plan Achros) could be around the $500 mark.

Still a stretch for detailed morphological analysis, but I'd think cell counting and a rough idea of shapes would be about as productive as on a new $3000 scope.

Apochronaut -- would you happen to know if the size of the phase ring for that listing is a match or good-enough-match for the ordinary Reichert 100x phase condenser and ring??

[apochronaut]

That particular objective, I have not used. It is being sold by someone that doesn't know microscopes very well ( he says that, not me), so the description that it was originally for such as the Univar isn't completely accurate. The optical characteristics are the same but Univars and Polyvars( ,maybe Polylites, too) had phase rings above the nosepiece in a rotating carousel, so objectives with phase rings were not required.
It therefore appears to be made for the Diavar 2, which was a similar microscope to the Microstar/Diastar group.

I have used a 40X .75 planachro phase, a 100x 1.25 planachro phase and a 100X 1.30 planfluor apo phase, from the same Austrian made series in a Diastar and all worked well. The 40X and 100X are about as good as the 40X .66 and 100X 1.25 phase objectives made for the series 400 in Buffalo. Perhaps the Reichert Austria objective is a shade better than the American one but that is to be expected with the .09 increase in N.A. The 100X planfluor apo works really well, although the background, rather than having a subdued grey, is more tan coloured; more along the lines of the character approaching an AO, B-Minus L. The Reichert Austria phase objectives are not parfocal with the American ones but the difference is probably shimmable.I don't have enough info on just what Reichert was doing with these objectives, only some older basic Diavar 2 info. The phase rings line up well and center well with perfect sizing in the bertrand lens on a Diastar. The planachros have about the same degree of halo , as I am used to with dark phase objectives but the planfluor apo has considerably less. I would think that the planapo phase in the listing should make a very good addition to a series 400 phase microscope.

[PeteM]

That particular . . ..

Thanks.

[apochronaut]

Here is an image of 1% homogenized milk, taken through the Reichert 100X 1.30 planfluor apo phase, mounted in an AO/Reichert Diastar with an AO 1205 phase carousel and a 1202 .90 achromat/aplanat condenser. The cropped frame is about 100 um. Large globes are fat, very small black dots are presumed to be spheroplasts and the black bacilli, thought to be b.cereus.

[Pine]

This does sound like your best bet.
Can stateside members come up with something?

Probably it is! The used microscope market is quite small here.


Regards,

Marcelo.

[Pine]

Marcelo,
What exact "bacterial morphological analysis" do you want to do with light microscope? If that really is your main goal, please explain it in detail and feel free to be technical. I should be able to understand it and help you (I have a PhD in Bacteriology).


For detailed bacterial morphological analysis, TEM is usually used. No light microscope is resolving enough.

Zzffnn,

Thank you!

I edited the message and some important words was missed: very basic morphological analysis!

I´m in the process of setting up a small brewery, so bacteria identification is limited to simple differential staining and some basic morphology. Fortunately, the number of bacterial genera that could survive in a brewing process are relatively small and such organisms
usually create by-products/off-flavors that help us a lot on the process of identification.

Lactobacillus and Pediococcus are the most common gram positive contaminants. Some Streptococcus (lactis more specifically) and bacilli are among other Gram positive. On the Gram negative side acetic bacteria from Acetobacter and Gluconnobacter genus, some Enterobacteriaceae (Obesumbacterium), Zymomonas (as an example I´ll be looking for motility and flagella trying to identify Z. mobilis).

"I think phase contrast and darkfield will be your best bet. Also specific staining and/or surface antigen analysis."

Most of time gram method are used but some very specific staining are used to identify some spoilage organisms. selective media
is a standard procedure, usually cycloheximide. I´m not sure of surface antigen analysis being used in a regular base.

I think phase contrast and darkfield could be useful and they are very, very nice as hobby .

"If you are coming to US, get a used AO 10/20/110/120 equipped with phase and darkfield. American Optical Spencer is a high quality US brand that dos not cost much. It offers one of the best performance for phase contrast at low budget. The models I suggested are infinity corrected, so you can have to used AO infinity objectives (160 tube length objectives won't work)."

I saw several people recommending AO Spencer, but I´m not used to this brand. Do you of some trusted seller/company that carries this brand?

I suggest a mirrorless camer, if you don't currently have any good camera. Or use a DSLR, if you already have one.

I have a Nikon D5100. I think it´s a better bet than a cheap USB camera but I need (please, correct me if I´m wrong) a trinocular head and a c-mount whit a specific correction lens to my camera sensor size.

Which brand and infinity or not depends on your application, specific needs and luck/budget. I prefer 160 tube length and use big brands myself, because I want water immersion (which is too expensive from infinity objectives) and like to mix-and-match different brands of 160TL objectives (which is not as easy with infinity objectives).

160TL are cheaper and can be mixed (at least if they have same threads). I really can´t see where is the advantage in inifity optics.
But I´m not used to infinity optics as it was not the standart when I was at university (late 80/mid 90s).


Best regards.

Marcelo.

[Pine]

Marcelo
For cell counting and viability tests, I think that direct operation (tethering) of the camera from a personal computer (laptop, desktop) is very benefical.
Mirrorless are advantageous relative to DSLRs and other cameras in some respects, but not all of them can be tethered.
Good luck.

Hobbyst46,

I´m testing a open source program called Nikon Camera Control. It can control Nikon DSLR using a laptop and USB port.

A friend of mine uses celular photos with imageJ.

Best Regards,

Marcelo.

[zzffnn]

Marcelo,

You want a wider T mount tube for your Nikon, not a narrow c mount tube (which is usually used for tiny sensors of USB cameras).

AO Spencer produced many good quality infinity phase objectives (and scopes), which are usually cheaper than most 160TL phase objectives made by other brands. AO made good 160TL phase objectives too, but those are older, harder to find and very slightly worse optically. I use 160TL AO phase objectives myself, but it took me a while to assemble a set in US.

Forum member Apochronaut or Charles may be able to sell you a scope or two. If they cannot, I will try to contact another seller from whom members here have bought before.

Selection pressure or surface antigen is used in research/medical microbiology / pathology labs for identification, along with genetic sequencing. I was not sure what your work setting is, so I did not mention everything. Those may indeed be overkill for brewery use.

[PeteM]

Just as a follow up, here are four of the microscopes available through our Children's Museum -- if your month in California brings you near the south Bay Area. The Leitz is phase contrast. All four (B&L, Leitz, Nikon, Olympus) could be had with a trinocular head. The B&L has (I think) phase lenses. The 100x lenses for all four -- as well as the other 50+ scopes -- are 1.25 NA oil plan achromats -- not higher NA apos or fluorites.

[75RR]

Looks like a feast.
For those of us who have not been to California, when you say "south Bay Area" you mean what - San Francisco, Los Angeles ... ?

[MicroBob]

160TL are cheaper and can be mixed (at least if they have same threads)..

There have been lot of different microscope systems with 160mm tube lenght where the optical components are not compatible or don't work together well. The tube lenght is only one aspect of four when it comes to compatability.
It is rare that they mix perfectly and many don't work together well. E.g. Objective lenght 32mm or 33mm or 36mm or 37mm or 39mm or 45mm..... Not nearly parfocal.
Mixing 160mm components is not easy, so compatability is not an advantage for 160mm optics.

Bob

[PeteM]

Looks like a feast.
For those of us who have not been to California, when you say "south Bay Area" you mean what - San Francisco, Los Angeles ... ?

It's the Santa Cruz Children's Museum of Discovery -- the "surf city" closest to San Jose (30 miles) and San Francisco (70 miles).

Just to add a point about 160mm tube optics -- most have moved to DIN standard objectives (45mm from turret face to slide). We've had no problems mixing Nikon on Olympus, etc. as long as the proper eyepieces are also used, though parfocal shims are often needed (even when all lenses are the same brand) to get a scope properly tuned.

[apochronaut]

Parfocality of microscope optics in the factory was usually accounted for within the shell of the objective. If you have seen an objective, that when the shroud is removed, has three little screw holes plugged with paint or a resin, those are set screws that are fixed after the lens pack has been moved back and forth to make it parfocal with it's mates. Swapping another even identical objective into a set often means a loss of precise parfocality. The question might arise as to why, two objectives of exactly the same design might not be parfocal?

They may be, if they are from the same production run or most likely won't be, if they are from another. The reason for this is that when a new batch of glass is acquired from a new smelt, the refractive index will most likely be slightly different than previous ones. Therefore, new lenses from the new glass(es) will have to be shimmed differently in the lens interspaces and parfocality will have to be adjusted when the objective is tested. Two identical objectives, rarely have the same shims, internally.

Bausch & Lomb had a super way of dealing with the problem. They had external set screws. If you look at the grip ring on the Balplan objectives, you will see a set screw. Loosening that set screw, allows you to turn the entire lens pack up and down in the barrel, using a pin wrench in the rear lens mount to turn down and the pin wrench to turn up, plus a little up pressure on the front lens mount. You can then precisely parfocalize, without shimming the base of any objectives.

In more modern infinity corrected objectives, those that are designed more with the aid of ray tracing, more precise machining and with more precise control of new synthetic glass formulas, parfocality is closer intrinsically in the objective and there is much less difference and necessity for adjustment. than in older objectives.

[apochronaut]

Looks like a feast.
For those of us who have not been to California, when you say "south Bay Area" you mean what - San Francisco, Los Angeles ... ?

It's the Santa Cruz Children's Museum of Discovery -- the "surf city" closest to San Jose (30 miles) and San Francisco (70 miles).

Just to add a point about 160mm tube optics -- most have moved to DIN standard objectives (45mm from turret face to slide). We've had no problems mixing Nikon on Olympus, etc. as long as the proper eyepieces are also used, though parfocal shims are often needed (even when all lenses are the same brand) to get a scope properly tuned.

Yes, I notice that you are using at least one ( maybe 2....can't see the other one clearly enough), Bausch & Lomb, Chinese made Galen 3 objectives on the Laborlux, along with German Leitz objectives.

[Pine]

Marcelo,

What exact "bacterial morphological analysis" do you want to do with light microscope? If that really is your main goal, please explain it in detail and feel free to be technical. I should be able to understand it and help you (I have a PhD in Bacteriology).

For detailed bacterial morphological analysis, TEM is usually used. No light microscope is resolving enough.

I think phase contrast and darkfield will be your best bet. Also specific staining and/or surface antigen analysis.

If you are coming to US, get a used AO 10/20/110/120 equipped with phase and darkfield. American Optical Spencer is a high quality US brand that dos not cost much. It offers one of the best performance for phase contrast at low budget. The models I suggested are infinity corrected, so you can have to used AO infinity objectives (160 tube length objectives won't work).

A limited amount of morphology can be done on bacteria with light microscopes of sufficient quality but as Fan says, it is mostly done with TEM. Having information about the context of your sample can assist in deduction. Yeasts are a little easier. You must have fluorite or apochromat objectives , and it helps for them to be plan and of fairly modern design, in order to get any image quality whatsoever with bacteria. Phase, DF, DIC and oblique are a must. Staining can yield some features, if you have a comparative reference. Objectives designed from about the mid-1980's forward are usually needed. Chinese microscopes with achromat or planachromat objectives will be useless for such a task. Chinese optics in general, are less good than quality optics made in Germany,U.S.,Britain,Poland,Russia and Austria from even the 1970's. There are some planF objectives being made of o.k. quality and the only real quality option for such a task comes from Motic, who make planapos, I believe. They begin to be pricey. Well outside what one would expect from a Chinese scope.
I recently had samples of milk from a small dairy that is having intermittent very premature spoilage problems. A handful of bottles, in batches, from most recent production runs are developing a cheesy nose 10 or more days before the BBD. The milk will not foam, which usually is caused by a low protein content. There is no clabbering, so the milk looks normal.
Under BF and DF, using 100X 1.25 N.A planachromats from 1990's mfg.( AO/Reichert, U.S.A. and Austria mfg.), only a fleeting hint of some movement was evident, parting the butterfat globules, here and there. With phase, muddy shapes of a very motile bacillus of some kind could be discerned but aside from the behaviour, no morphology of note could be discerned. However, using a planfluor apo 100x 1.30 phase objective, captures with enough detail to get a fix on the species( spores, size and some inclusions) could be made. Combined with the behaviour ,context and protein destruction in the milk, B. Cereus seems the most likely culprit. It is a post pasteurization survivor, forms biofilms and hydrolizes casein. ....but most of that deduction was done using information other than bacterial morphology, however.

apochronaut,

First of all, thank you!

I think I´m in the same ship as this small dairy. In a brewery most of the identification methods are based on taste/odor and sometimes bacterial colony patterns. Basic bacterial morphology can help to differentiate some microorganisms.

What I need is a way to identify the presence of bacteria and their basic morphology (bacilli, Cocci, Strepto..., Staphilo... etc). Viability tests are made under 400x BF microscopy and ideally, one should identify the presence of bacteria at this magnification.
Specifically to detect presense of bacteria we use 1000x magnification in BF (DF and Phase opitionally). The number of rods and cocci per 100 yeast cells are reported and a sample is plated for viability.

About the lens I do not have your expertise, but in my experience a C. Reichert with more than 50 years generate better imagens than a 5 years old Labomed I used at university (last 80 / mid 90s).

Best regards,

Marcelo.

[Pine]

My suggestions;

Used big brand - vs. - new no big brand - vs - new big brand entry level?

If you can inspect a used big brand try that. Your first time should warn you as to what you might get.

Jim,

Thank you for your thoughts!

I don't have the expertise to evaluate an used microscope. I can check if it works, general state of the lens (mold, scratches ), focus and stage movement, but nothing beyond that.
Maybe a refurbished microscope is a good idea to take an used brand scope at the right price.

"New no big brand" would be my choice unless you want to spend a fair bit of time finding and replacing bad used parts. BTW, Amscope and Omax are esentialy the same.

I never did maintenance in microscopes, only used it.

"New big brand entry level" - absolutely not.

Infinity - vs - 160 TL?

160 for sure. See this site:

http://www.microbehunter.com/should-i-b ... ed-optics/

I´ll check, thank you!

USB camera - vs. - cmount for DSLR?

DSLR for sure. Sensor size, resolution, shutter speed, ISO, etc and if it is a Canon you can tether it to a computer with remote shooting.
[/quote]

I have a Nikon I can control from my laptop.

Best Regards.

[Pine]

Infinity - vs - 160 TL?

160 for sure. See this site:

http://www.microbehunter.com/should-i-b ... ed-optics/


JimT

The only problem is that some of that information isn't correct. There is more interchangeability than is indicated in that little chunk of info. and all of the optical refinements by the major manufacturers over the past at least 25 years in all cases, 40 years in another and almost 60 years in another have been in infinity correction. Without a doubt, all of the best optics in existence have been built for infinity systems. That isn't because infinity correction is inherently superior, it is because since about 1995, no one has been engineering the best microscope optics for fixed tube microscopes.
You can buy a 150.00 used microscope that is infinity corrected from at least 2 manufacturers right now and upgrade it with optics that were designed in 2010. You cannot improve fixed tube microscopes much beyond the state of the art that existed , at the time the company that made them abandoned the principle.

apochronaut,

You pointed something I asked in my original message. If optics evoluted a lot in last decades and best manufacters only did inifinity optics,
maybe inifity optics is now superior than old TL160.

You can buy a 150.00 used microscope that is infinity corrected from at least 2 manufacturers right now and upgrade it with optics that were designed in 2010. You cannot improve fixed tube microscopes much beyond the state of the art that existed , at the time the company that made them abandoned the principle.

which manufacturers do you recommend?

Best regards,

Marcelo.