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Objective Upgrade?
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Claytown



Joined: 25 Feb 2018
Posts: 17

PostPosted: Sun Feb 25, 2018 1:19 pm    Post subject: Objective Upgrade? Reply with quote

Hi all, this is my first post on here. I'm a hobbyist of all sorts and recently have been wanting to get close abstract shots of mainly crystal structures. I'm using the AmScope M150C along with their DSLR adapter on my Canon T2i. I'm wondering what the best bang-for-my-buck upgrade would be in order to get sharper images for possibly making something like a 16x20 print. I was thinking of possibly getting a Plan Apo lens if it could be within a few hundred dollars (possibly used). Would this be a possible upgrade for my microscope and what specs would I need to look out for to ensure it matches? Also, would the DSLR adapter possibly be holding back my sharpness a bit?

Heres a sample shot of where I'm at so far:


100% crop:
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Ichthyophthirius



Joined: 07 Mar 2013
Posts: 800

PostPosted: Mon Feb 26, 2018 4:32 am    Post subject: Reply with quote

Hi,

To say anything, let us know what objective(s) you're using. There is no scale bar in your image, so it's hard to access the sharpness. From a certain NA upwards (0.35), samples require a coverglass and from a higher NA upwards (0.65), the coverglass must be within a tight thickness range.

The object must also reside directly underneath the coverglass for high NA objectives so good sample preparation is essential. If you currenly grow your crystals on a slide, try to grow them on the coverglass instead.

With high magnification objectives (like a 100/1.25) the number of pixels required to show all the image information is actually quite low. It's not worth blowing up the size for those images.

To access your DSLR-adapter, it would be best if you take some test images of a stage micrometer (don't forget to add a coverglass if the stage micrometer doesn't have one yet). It will give you an idea of distortion and colour fringing.

Regards, Ichty

P.S. The sharpest images I usually get with low-magnification high-NA oil immersion fluorite objectives (as you would expect) and these aren't the most expensive ...
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Claytown



Joined: 25 Feb 2018
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PostPosted: Mon Feb 26, 2018 10:48 am    Post subject: Reply with quote

I believe this was the lens I was using


It might be important to note that the image was focus stacked

The crystals were grown directly on the slide without a coverglass
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Ichthyophthirius



Joined: 07 Mar 2013
Posts: 800

PostPosted: Mon Feb 26, 2018 1:38 pm    Post subject: Reply with quote

Hi,

The stacking makes it hard to judge. Maybe someone else can help you with that.

However, to judge the DSLR adapter, you should take some test shots with a stage micrometer (single shots, no stacking).

P.S.: Don't forget you can also stich together several fields of view, which gives nice images for large prints.
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Claytown



Joined: 25 Feb 2018
Posts: 17

PostPosted: Tue Feb 27, 2018 12:07 am    Post subject: Reply with quote

I tried the stitching thing, but ran into the issue not having sharp enough edges to make for a consistent image (also the lighting would shift a bit as the slide was panned)

Is there a good 10x or 20x Plan Flourite objective you could recommend that would be compatible with my scope?

Would this work?
http://www.amscope.com/accessories/objective/10x-infinity-corrected-plan-fluor-objective-lens.html

Or even something wonky like this for a 40x?
https://www.ebay.com/itm/Nikon-Fl-Plan-40x-0-75-160-0-17-Microscope-Objective-Fluor-Fluorite-/322081194426?_trksid=p2385738.m4383.l4275.c10

I'm having a tough time understanding what to look for as far as compatibility

Edit: Also, here's a link to my scope if you need the specs
http://www.amscope.com/40x-1000x-student-compound-microscope-with-mechanical-stage-and-coarse-fine-focus.html
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Pau
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Joined: 20 Jan 2010
Posts: 4428
Location: Valencia, Spain

PostPosted: Tue Feb 27, 2018 2:24 am    Post subject: Reply with quote

Hi Claytown,
First, welcome to the forum!

About objectives compatibility:
In principle your scope can mount any DIN objective (RMS mount, 45mm parfocal, 160mm tube length corrected) but many old 160 objectives do need compensating eyepieces to complete the objective correction and this is not standardized between makers so they need matched eyepieces from the same maker and series. The main exception is the Nikon CF series.

You could mount infinite corrected objectives but they will not work well because they need a tube lens near the objective to project a real image at the right distance (and in some makers like Zeiss and Leica this tube lens also has aberrations compensation built in). The Amscope 10X you linked is not a good option for this reason.
The ugly looking Nikon you linked is older than the CF series, so it needs compensating eyepiece and it's also shorter than DIN so maybe you even couldn't get focus.

All this narrows the options to:
- Nikon CF or CFN 160 objectives, likely the simpler well proven way
- Matched DIN objective and eyepiece combos from Leitz, Zeiss, Zeiss Jena, Olympus and few others
- New generic chinese Plan objectives from Amscope or similar white brand. Some are pretty good, others are bad...
- If you can raise enough the stage you could also look for 160 corrected short barrel matched objective and eyepiece combos from Nikon, Lomo, Leitz (170 corrected but OK), Olympus. etc. Short barrel is not standardized, being parfocal at 33mm to 37mm depending of the maker.

For high magnification you could be limited by the poor single lens condenser of your instrument

How do you couple the camera to the microscope? Please link the adapter. If your adapter doesn't have the eyepiece inside as I think it will work badly with objectives that need compensating eyepieces. With those objectives you need to use an afocal setup.
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ChrisR
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Joined: 14 Mar 2009
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Location: Near London, UK

PostPosted: Tue Feb 27, 2018 3:26 am    Post subject: Reply with quote

A bit tangential, but it was found that an Amscope $17 (!) objective was very good, in comparison with more expensive others.
So I bought a used Amscope 4x fluor to try. Great in the middle, but a very small "good" image circle Sad.

There was an "Edmunds Finite Conjugate" 10x which did well I remember, though I don't have one.

I'll look for links...


Edit:
here - http://www.photomacrography.net/forum/viewtopic.php?t=9393

Edmunds, currently $89
https://www.edmundoptics.com/microscopy/finite-conjugate-objectives/10x-nikon-achromatic-finite-conjugate-objective/

This won't need eyepiece correction, or even an eyepiece, but I don't know what image circle you'll see if you use direct projection.
As Pau asked, how are you connecting your camera?
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Ichthyophthirius



Joined: 07 Mar 2013
Posts: 800

PostPosted: Tue Feb 27, 2018 5:49 am    Post subject: Reply with quote

Claytown wrote:
I tried the stitching thing, but ran into the issue not having sharp enough edges to make for a consistent image (also the lighting would shift a bit as the slide was panned)

Is there a good 10x or 20x Plan Flourite objective you could recommend that would be compatible with my scope?

Would this work?
http://www.amscope.com/accessories/objective/10x-infinity-corrected-plan-fluor-objective-lens.html

Or even something wonky like this for a 40x?
https://www.ebay.com/itm/Nikon-Fl-Plan-40x-0-75-160-0-17-Microscope-Objective-Fluor-Fluorite-/322081194426?_trksid=p2385738.m4383.l4275.c10

I'm having a tough time understanding what to look for as far as compatibility

Edit: Also, here's a link to my scope if you need the specs
http://www.amscope.com/40x-1000x-student-compound-microscope-with-mechanical-stage-and-coarse-fine-focus.html


Hi,

I agree with what Pau said. So just to reirrerate:

- infinity-corrected objectives are not the best choice; stick to 160 mm tube length objectives (a 10x might work on 160 mm but it's not using its full potential)

Two main choices:

a) Nikon CF or CFN (160 mm) objectives do not require compensating eyepieces. They might be usable with your existing DSLR-adapter.

However, for this you have to run a test with a suitable test object, like a stage micrometer, to access the performance/suitablility of the adapter. There is no way around this and you need a stage micrometer for scale bars anyway.

b) Change your setup to afocal (clamp adapter, 10x eyepiece "glasses" or "high eyepoint", 40 mm prime lens for camera, maybe a little tripod for the weight of your camera). Pau has shown his afocal setup here previously.

Can be done for any manufacturer (including Nikon) as long as you combine matching eyepieces and objectives from each manufacturer.

Leitz is the best value for money (NPL Fluotar 10/0.30, 16/0.45, 25/0.55, 50/1.00 oil, work well with simple polarisation microscopy; combined with a Periplan "10x/18" glasses eyepiece) - but any of the others will work just as well! The choice of manufacturer is largely down to personal preference and budget. The NPL Fluotars are around $100 each which seem to fit your budget but there is the additional cost of setting up afocal!


- Do you shoot your Canon directly from LiveView through a computer? That's important to minimise vibrations.

- For all objectives NA > 0.4 you should grow your crystals directly on the coverglass (then turn it over for microscopy) if at all possible.

Regards, Ichty
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Claytown



Joined: 25 Feb 2018
Posts: 17

PostPosted: Tue Feb 27, 2018 10:37 am    Post subject: Reply with quote

Thanks for all the great info guys,

Here is a link to the dslr adapter I am using:
http://www.amscope.com/canon-slr-dslr-camera-adapter-for-microscopes.html

I'm having a tough time finding Nikon CF and CFN lenses. Are they an older line? Will the CFI lenses work? I found some Nikon CF Plan lenses on ebay, but they do not say they are fluorite, so would that mean they achromatic? Would this affect my image quality greatly compared to a fluorite lens? Would it be more advantageous to have a Plan Achromatic or a regular fluorite?

Sorry for all the questions, the information available is quite scattered out there!

Ichty, I will invest in the stage micrometer
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phil m



Joined: 10 Aug 2014
Posts: 156

PostPosted: Tue Feb 27, 2018 10:57 am    Post subject: Reply with quote

Leitz 160mm objectives were derived from Wild optics, since Wild had anincreasing ownership of Leitz, after the early 70's to full ownership by 1985. Switching over to 160mm was the only option for Leitz, in order to stay in business. So, searching out some Wild fluotars is the best option for upgrading from D.I.N. 160mm planachros of any kind.

A huge slew of them recently sold on ebay , many for less than 50.00 and some of them N.O.S.

I too bought into the Amscope 4X and 10X infinity corrected PlanF objectives; more as a test than with any hope for improvement to my system. It only helped to bolster my dim view of Chinese optics. Most of the designs haven't changed since the early 80's, and they were well behind then. I have catalogues from the period and many of the microscopes and objectives are still the same or very similar.
Here is my test of the Amscope 4X and 10X planF, I extracted it from a thread on another forum, to save having to wade through the entire thread.

I decided to buy a couple of these, since the price was still pretty low. Eventually, with the exchange to $CDN., Amscopes asinine shipping costs outside the U.S. and the Canadian government's asinine rakeoff at the border, the pair ended up costing me about 300.00 $CDN. That isn't too terrible for a pair of new planfluorite infinity corrected objectives, if they were to perform well and I am also interested to know, how the Chinese makers are forging ahead. This is a good test.

The first thing that I noticed is the weight of the Chinese objectives, and the diameter. They are fairly heavy, so lots of glass in there, and the coating looks impressive. The barrels and finish are only adequate but then all objectives over the past 25 years or so have declined in finish, with paint replacing etching etc.


The two objectives are marked 4X .13 PlanF and 10X .30 PlanF. I am comparing them to a 4X .12 Planachro from AO/Reichert circa 1985, a 10X .25 Planachro from the same series AO/Reichert and a 10X .30 Planfluor AO/Reichert of the same vintage. I could buy the two AO/Reichert Planachros used for around 75.00 ea., if I look around but the 10X .30 Planfluor might cost about the same as the Amscope or around 150.00. I have seen them go much cheaper in the past, though. All of the objectives are 45mm parfocal D.I.N.


The Amscope 4X is quite short and fat, 28mm long , weighing 81 gm., the AO/Reichert 4X is much longer at 38mm, weighing 102 gm. The Amscope 10X is also shorter(32mm) than the two AO/Reichert(40.5mm)and the respective weights are 88 gm., 106 gm. and 98 gm. Based on this length difference, I would expect the two Chinese objectives to have longer working distances.
They were tested in a Reichert Diastar, with a 20mm f.o.v.

The Amscope objectives appear to be corrected for a 200mm infinity tube, with the magnification equaling that of the objectives I am comparing them against. They both parcenter well, with the 4x Being a little off.
They also appear to have a field limitation. Many of the Chinese microscopes are sent out with 18mm f.o.v. eyepieces and that seems to be the limit that these objectives have plan performance up to. With a 20mm f.o.v., there is some falloff over the perimeter 2mm of field, with some flare and lateral chromatic aberration occurring. It isn't too much of a problem but the characteristic begins slightly before an 18mm diameter, so they are not fully plan. This is is definitely disappointing and it is easy to see that the performance of these is cut very close to the bone, obviously as part of the cost cutting structure of their offering.

The 4X .13PlanF vs. the 4X .12 Planachro. The first thing noticeable is that the Amscope is brighter than the AO/Reichert objective. Colour is more intense , although the background has a blueish cast and the contrast is a little higher. Using the aux. condenser lens on the AO/Reichert abbe aspheric condenser, the field is just barely filled with the Amscope objective , due to it's longer w.d., which is equal pretty much to the 10mm difference in the their length, since the two are almost perfectly parfocal. The Amscope has noticeably better resolution in the center of the field but that advantage begins to fall off at about the 16mm f.o.v. point as the AO/Reichert's superior planarity and edge correction dominates. AO/Reichert's achromat objectives of this period were close to fluorite performance, when it came to colour correction, so with low refraction specimens the two objectives perform about equally in that regard but with specimens of a higher refaction, such as diatoms, the AO/Reichert planachro has a slight edge in the center of the field with a decided edge towards the periphery.
Overall, as a low power scanning objective the AO/Reichert presents a more pleasant wide field experience but for critical examination of details in the center of the field, the Amscope objective has an edge in resolution and contrast

The 10X .30 PlanF vs. the 10X .25 planachro and the 10X .30 planfluor. Again, the planarity falloff of the Amscope objective is noticeable but not as evident as it is with the 4X. Brightness and contrast of the three is almost identical, with the AO/Reichert Planfluor having a slight edge.. At the center of the field, the Amscope PlanF and AO Planachro are pretty much identical in resolution, with the AO/Reichert Planfluor being noticeably superior in bringing out the fine details of very finely structured diatoms, for instance. Both of the AO/Reichert objectives are superior outside of about the 75% of the field center. With specimens of higher refraction, the Amscope objective elicits a decided irridescent internal c.a in many structures, across the field while the AO planachro and planfluor elicit almost none. In this regard the AO/Reichert planfluor is only slightly better than the planachro. The three objectives are parfocal, so the Amscope example has about a 9mm advantage in w.d.
Overall, there is virtually no advantage of the Amscope 10X .30 objective over a higher grade planachro, with the objective really just performing about at the level of such a specification. Pretty disappointing really, given that AO/Reichert 10X .25 infinity corrected planachros are almost a dime a dozen.
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Claytown



Joined: 25 Feb 2018
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PostPosted: Tue Feb 27, 2018 11:23 am    Post subject: Reply with quote

Wow, that's a lot of information to soak up. So I'm gathering that it really depends on how well built the lens is, not the type of lens it is? The type of lens really only provides general resolution trends provided it's made by a reliable brand?

Would this lens work well for me then as an upgrade?
https://www.ebay.com/itm/Wild-Heerbrugg-Fluotar-10X-0-40-Microscope-Objective-Lens/172869684451?epid=2152068735&hash=item283fd60ce3:g:oz8AAOSwI7tZvqV3
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Pau
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PostPosted: Tue Feb 27, 2018 11:31 am    Post subject: Reply with quote

Yes this is the adapter I was thinking of, it doesn't do compensation so it needs full corrected objectives.
Few forum members have posted about it with mixed results.

http://www.photomacrography.net/forum/viewtopic.php?p=140518
http://www.photomacrography.net/forum/viewtopic.php?p=166055
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Ichthyophthirius



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PostPosted: Tue Feb 27, 2018 1:01 pm    Post subject: Reply with quote

Claytown wrote:
Would this lens work well for me then as an upgrade?

Wild-Heerbrugg-Fluotar-10X-0-40-


It is a very nice objective (good correction and high NA for the 10:1 magnification),
however, Wild objectives have a 37 mm parfocal length. This means the distance between the objective base and the object is 8 mm shorter than usual for a DIN objective (45 mm parfocal length). Some microscopes can't raise the stage far enough to accommodate these short barrel objectives. So check yours before you buy.

It's also not a plan objective (in contrast to the NPL Fluotars I mentioned) though it has a higher NA than the NPL Fluotar 10/0.30 from Leitz.
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ChrisR
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PostPosted: Tue Feb 27, 2018 1:12 pm    Post subject: Reply with quote

If you check the reference given for the Edmunds Finite Conjugate, you'll see that although it is't quite as sharp in the center as a Nikon CF (that's reasonable, the NA is 0.25 vs 0.30), it's much better at covering the APS sensor. It matters, if you go close to your 20 x 16s!
I don't know how big the usable image circle is with Leitz objectives, I have some but have only eyeballed through them!
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Ichthyophthirius



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PostPosted: Tue Feb 27, 2018 1:42 pm    Post subject: Reply with quote

ChrisR wrote:
I don't know how big the usable image circle is with Leitz objectives, I have some but have only eyeballed through them!


Most only work well in afocal, with a Periplan eyepiece. Image circles are at least FN 22 for NPL Fluotars, FN 25 for PL Fluotars and FN 28 for PL Apos (according to the Leitz literature).
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