Beginner question: microscope or just microscope lenses

Starting out in microscopy? Post images and ask questions relating to the microscope and get answers from our more advanced users on the subject.

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Sievers
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Beginner question: microscope or just microscope lenses

Post by Sievers »

Hi there

I've been wanting to get into the world of microphotography and I notice that there are those who use actual microscopes with adapters to mount SLR cameras on top and there are those who use microscope lenses and tubes and mount those directly on the camera instead. Beyond the issue of shakiness in the latter I can't seem to figure out which advantages/disadvantages the two setups has. Due to shakiness it is clear to me that the latter setup is somewhat limited in degree of magnification (max around 20X as far as I understand) but is the only reason for going beyond microscope lenses and buying an actual microscope that you get a greater level of magnification? Am I missing something? Is the image quality better when just using microscope lenses directly on a camera, etc?

Cheers

Jakob

rjlittlefield
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Post by rjlittlefield »

Jakob, welcome aboard.

Image quality is identical in both cases.

Advantages to the microscope are that you buy an off-the-shelf piece of equipment that has an integrated illumination and focusing system optimized for looking at things that are typically less than 10 mm in maximum dimension. Disadvantages are that looking at anything larger will be difficult or impossible, positioning of a 3D specimen is relatively difficult, and the specimen sits on a large and mostly opaque stage so that some angles of illumination are not possible.

Advantages to open systems (lenses on camera) are complementary to that. Open systems scale conveniently to much larger subjects, positioning of 3D specimens is relatively simpler, and the subject can be mounted so as to illuminate from any angle not blocked by the objective. Disadvantages are that specialized illumination such as phase contrast and DIC are not feasible, there are no eyepieces so that direct visual observation is not possible, and (as you noted) the open systems are less rigid.

A good short summary is that open systems are optimized for looking at opaque 3D subjects, while most microscopes are optimized for looking at flat transparent ones.

A side effect of this is that open systems are usually used at lower magnifications. The issue of shakiness is certainly present, but it's less important than you indicate. The main reasons that open systems are usually used at 20X or less are that 1) higher power objectives with long working distance are relatively expensive or difficult to find, and 2) because of an assortment of optical effects, it is challenging to focus-stack while using the wide apertures that necessarily go along with high magnification (to avoid diffraction).

As an example of the different targets, consider that I used an open system at up to 50X on sensor (what you would see through a microscope at 500X) to photograph an opaque abrasive tool HERE, but switched to an ordinary microscope to photograph a thin sample at only 10X on sensor HERE.

Does this help?

--Rik

Pau
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Post by Pau »

Hi Jakob, welcome aboard!

The answer to your question could be very long, so I think that it's much better to beguin posting your goals, mainly kind of subjects and magnification range you're intersted on.

In short:
* Microscopes are in general better for
- High magnification (as you say)
- transparent subjects rear illuminated (trasmitted illumination)
- small flat subjets thant can accomodate in the microscope stage, usually between both glasses in a typical microscope slide
-to have direct optical vision (through the eyepieces)
- to quickly change magnification

It is indispensable for:
- use of immersion objectives
- advanced contrast techniques (phase, DIC...) with transmitted light
- microscope objectives that need optical corrections done at the eyepiece or tube lens

* Objectives on tubes or bellows are in general better for:
- subjets that not accomodate in the microscope frame or that need statial orientation (a whole insect, for example)
- moderate magnification in setups compatible with macro lenses for low magnification
- incident diffuse illumination with opaque subjets

I'ts more flexible and prone to make DIY setups

* In some cases both approaches can work very well

* There are intermediate possibilities, often derivated from industrial microscopes

(well, Rik was faster again!)
Pau

rjlittlefield
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Post by rjlittlefield »

Pau wrote:(well, Rik was faster again!)
This is surely a matter of sheer luck. 5 hours after the question is asked, two people decide to answer it, from almost opposite sides of the world, only 11 minutes apart?! :?

I'm just happy that the two answers are consistent with each other!

--Rik

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Post by ChrisR »

HI Jakob
One other thing, do you prefer to work with a vertical or horizontal setup?

Broadly:
Microscope arrangements are only usable horizontally with modifications, even if only to add a spring to bias the focus, and stiffening to make the stage work without slipping.

Open setups are easier to arrange horizontally, especially regarding rigidity.
Starting with a part-microscope, with a bellows on the "head" and by removing the stage, as here:
http://photomacrography.net/forum/viewt ... 2049#82049
it is possible to get larger subject sizes than 10mm, though you need a suitable lens. There are some with rms thread, but not many.

Nurz
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Re: Beginner question: microscope or just microscope lenses

Post by Nurz »

Another thread resurrected.
rjlittlefield wrote:
Thu Jul 02, 2015 7:28 am
I used an open system at up to 50X on sensor (what you would see through a microscope at 500X)
Can you elaborate on this? I thought an objective on a DSLR gives more or less its nominal magnification.

Generally, which compound microscope is considered a good starting point for beginners, preferably that works with both reflected and transmitted light? And which Nikon DX crop adaptor you recommend (I suppose one that uses the eyepiece) in order to get a full 500x-1000x in good quality?
Vasilis

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Re: Beginner question: microscope or just microscope lenses

Post by Lou Jost »

While we are resurrecting this old thread, I'd like to add my two cents to the original poster's question. An advantage of the extra rigidity of a microscope is that it can be used even when working distances are a small fraction of a millimeter. Short working distances like this are common for high magnification objectives. So that is another important way in which microscopes are optimized for high m. Most open systems are rigid enough when left untouched, but have some slight flexibility when touched, and this could be enough to do damage if working distance is really small. Open systems can be used at high m but only if you don't ever touch the camera.

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Re: Beginner question: microscope or just microscope lenses

Post by rjlittlefield »

Nurz wrote:
Sun Apr 17, 2022 8:33 am
rjlittlefield wrote:
Thu Jul 02, 2015 7:28 am
I used an open system at up to 50X on sensor (what you would see through a microscope at 500X)
Can you elaborate on this? I thought an objective on a DSLR gives more or less its nominal magnification.
It does, but remember that that magnification is specified on sensor. Then the image on sensor gets further enlarged to a size that is conveniently viewed by a human. The same thing happens in a microscope, with the enlargement being determined by the power of the eyepiece. By far the most common eyepiece magnification is 10X, in which case a 50X objective gives "500X" magnification. In both cases, the level of detail eventually seen by the human will be limited by the resolution of the objective, so one might simply say "this was shot with a 50X NA 0.55 objective". But in my experience people have some idea what they might see through a microscope at 500X, and no idea what they might see with 50X direct projection to a DSLR. So for the sake of clear communication with people I don't know, I like the phrasing "would see through a microscope at 500X".

Generally, which compound microscope is considered a good starting point for beginners, preferably that works with both reflected and transmitted light? And which Nikon DX crop adaptor you recommend (I suppose one that uses the eyepiece) in order to get a full 500x-1000x in good quality?
I generally use direct projection onto a DSLR sensor, no eyepiece involved. APS-C sensor size is well matched to the usable image circle of most objectives, so when it's possible to just replace the eyepiece with a sensor, that's the way I go because it gives a lot less chance for aberrations to get added by the eyepiece and other relay optics.

There's also a lot to be said for the "afocal" approach in which you place a camera with a suitable lens above the eyepiece of the microscope, essentially just replacing the human's eye with the camera's lens and sensor. It turns out that many cell phone cameras work very well in this mode. For use with a DSLR, one of the new thin "pancake" lenses is usually the best bet.

As for which scope, that's a tricky question. One line of thought says that best value is an older scope that was high quality when new and has just been superseded in the usual turnover of equipment from university or industry. That presumes, however, that you can find such a scope that is still in good operating condition or has been refurbished to replace hardened lubricant and so on. A second line of thought suggests to buy a new scope from a low end but well known source such as Amscope, recognizing that for sure it's not going to give research quality results but it's low risk because either there's nothing wrong in the first place or it's replaceable under warranty.

If you have access to a seller of used microscopes, it would definitely be worth your time to talk with them and see what they can do for you. If you do not have such access, then from personal experience I can say that I regularly use the Amscope T490 that now sits on one of my tables, but I would run screaming from an Amscope M150. There is some discussion of these at viewtopic.php?t=24554 and viewtopic.php?t=24552. Those discussions concentrate on the focus blocks. The optics are just sort of "OK", not notably good or bad.

--Rik

Lou Jost
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Re: Beginner question: microscope or just microscope lenses

Post by Lou Jost »

One line of thought says that best value is an older scope that was high quality when new and has just been superseded in the usual turnover of equipment from university or industry. That presumes, however, that you can find such a scope that is still in good operating condition or has been refurbished to replace hardened lubricant and so on.
This is the approach I have used, and I am very glad of it. Excellent used microscopes can be had on eBay for a tiny fraction of the cost of a new one, and the associated accessories are also available on eBAy for very little money. The cost is so low that you can buy multiple replacements for broken ones and still save vast amounts of money over the price of a new one. For a first microscope I think a really good brand's old models are less frustrating than a cheap brand's new model.

Nurz
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Re: Beginner question: microscope or just microscope lenses

Post by Nurz »

Thank you for the clarification and advice. Bear with me if you will, I'm trying to specify the amount of magnification an objective can give in different configurations, within a consistent level of IQ. If a 300mm focal length on a crop sensor gives a (300 x 1.5) / 50 = 9x eyepiece equivalent, then a 10x objective should give a total of 90x, almost as much as the common 10x microscope eyepiece.

Quality is subject to glass but, for the sake of discussion, let's say all lenses are capable of producing a good image. How different are the results in size and quality, when I take a picture with...
... sensor -> microscope or extension tube -> 10x objective
... sensor -> 10x eyepiece -> microscope -> 10x objective
... sensor -> pancake lens -> microscope -> 10x objective
... sensor -> pancake lens -> 10x eyepiece -> microscope -> 10x objective
... sensor -> telephoto lens -> 10x objective
... sensor -> tube lens -> extension tube -> 10x objective

What's the largest image I can get before it starts to soften? I want to add and weigh this parameter as well, in all the advantages and disadvantages that you people have mentioned for either method.
Lou Jost wrote:
Sun Apr 17, 2022 11:32 am
For a first microscope I think a really good brand's old models are less frustrating than a cheap brand's new model.
I'll keep this in mind.
Vasilis

Scarodactyl
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Re: Beginner question: microscope or just microscope lenses

Post by Scarodactyl »

Don't get too hung up on the 10x eyepiece. The eyepiece magnifies the image but your eyelens just demagnifies it right back down while putting it onto your retina.

Adalbert
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Re: Beginner question: microscope or just microscope lenses

Post by Adalbert »

Hello Jakob,
But you can use both solutions separately or mixed.
I often combine parts of the microscope with the home-made setup.
e.g. https://www.facebook.com/photo/?fbid=47 ... 0269581589
Best, ADi

Nurz
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Re: Beginner question: microscope or just microscope lenses

Post by Nurz »

Scarodactyl wrote:
Mon Apr 18, 2022 5:31 am
Don't get too hung up on the 10x eyepiece. The eyepiece magnifies the image but your eyelens just demagnifies it right back down while putting it onto your retina.
Thanks, you nailed it. This is one of the essential things I was missing, and was confusing me from the start. What I see through the 10x eyepiece is what I capture with the naked sensor. Now I get why Rik says what he says.
Vasilis

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