Tube lens and microscope objective questions

[wbodine]

I have an Amscope Plan 4X finite microscope objective that I have successfully used. I now want a more extreme macro and would like to go to a 10 X magnification. I am using an older full frame Canon 5D Mark ll, all on a fixed StackShot rail.

MICROSCOPIC OBJECTIVE
Why is the Nikon objective twice as expensive as the AmScope objective?
When I contacted AmScope technical support, they only explained " don't know why Nikon is charging the prices they do for similar products."
Does Nikon have more elements?
Are the Nikon elements glass vs. plastic?
Is it that much better?

Will the AmScope infinity corrected objective, PLAN 10X (WD 14.86mm) work as well as the more expensive Nikon?

TUBE LENS
Will the Vintage Canon EF-100-200mm F/4.5 A AF Zoom Lens work as well as the Canon EF 80-200mm F/2.8 L AF Zoom Telephoto Lens?
How important will the faster f2.8 lens be for detail or can I use the slower lens? Does it matter much?

[Lou Jost]

This is no different than asking why a Mercedes costs more than a Volkswagen. Price differences are due to a mixture of brand name recognition and technical quality. Designing a good microscope objective is an extremely difficult technical task, and in addition, building one requires immensely careful quality control. This costs money. On the whole, Nikon has immensely greater optical experience than Amscope, and far more manufacturing experience.

Every now and then a small company manages to surprise the world with a super-cheap item that works as well as a much more expensive one, but it is not common.

[PeteM]

Even given a nearly identical optical design, with lens elements produced on CNC grinders, there are several steps the better makers may take:

- better glass to improve corrections and also achieve a higher numerical aperture
- better lens coatings to reduce reflections and improve contrast
- metal rather than plastic spacers and shims
- more care in manufacturing to assure that objectives from the same family are parfocal and parcentered
- lens assembly in clean rooms to avoid dust between elements
- better QA and outgoing inspection
- dealer and/or manufacturer support

Parfocal and parcentered objectives are not a concern for a single lens used in photomicrography, but important when switching between objectives on a turret.

[wbodine]

So I guess the basic question is,
1. Will I be dissatisfied with sharpness and vignetting if I use the less expensive AmScope lens?
2. Does the faster f2.8 vs f4 tube (or rely lens) make any quality difference in quality?

[Lou Jost]

Nobody except you can answer your first question. Depends how fussy you are.

No, f/2.8 provides no advantage over f/4 in a tube lens, if all else is equal.

[lothman]

1. Will I be dissatisfied with sharpness and vignetting if I use the less expensive AmScope lens?

google finds this
https://www.fotomacro.cl/amscope-plan-1 ... -plan-10x/

[wbodine]

Thanks for the Nikon vs AmScope comparison. Even I can see the difference as we move further from the center.

[rjlittlefield]

Thanks for the Nikon vs AmScope comparison. Even I can see the difference as we move further from the center.

That reference provides a good illustration of some general issues.

I do not know of any comparison between the specific objectives that you asked about.

I do know, from many sources including personal experience, that the specific Nikon objective you ask about is an excellent performer with a particularly wide field. It easily covers full frame at rated magnification, and when used on APS-C with a 100mm tube lens, it provides the sharpest 5X in my kit. See viewtopic.php?t=15876 for discussion about that. Its main drawback is quite a bit of longitudinal chromatic aberration, which causes yellow or blue/violet color casts particularly in out-of-focus regions. See viewtopic.php?p=147672#p147672 for some illutration. That issue tends to disappear in stacking, so it's not a big problem with most subjects.

However, if you can afford to give up some working distance, there is a less expensive Nikon objective that has very similar performance. That is the Nikon CFI BE 10X NA 0.25 WD 6.7 (part number MRN70100, currently available HERE). See viewtopic.php?t=16348 for illustration (again at 5X on a 100 mm tube lens).

Back to general issues, there is a world of difference between the target markets of AmScope and Nikon.

To illustrate, here is what appeared just now when I simply pointed my browser at https://amscope.com :

Very briefly, Nikon targets from research applications down to university student scopes, while AmScope targets from K-8 children up to, um, it's a little hard to tell because their advertisements have historically been loaded with puffery, some of it obvious, some not.

This is not to say "Amscope bad". Several years ago I bought what was then one of their mid-range compound scopes, thinking that I was going to evaluate and return it, but actually I ended up keeping the thing and I use it often for routine visual observation. Some of that story is recounted at viewtopic.php?t=24552 (the one I kept). On the flip side, at the same time I purchased but then returned another model after finding serious deficiencies including misleading markings and documentation. See viewtopic.php?t=24554 for that one. So it's a mixed bag. My gut feeling is that AmScope's stuff is fairly priced, if you take advantage of one of their frequent half-off sales and carefully check out what you received while you can still return it.

By the way, I notice that over the years AmScope's high end offerings have grown to be much higher end, with correspondingly higher prices. I have no information about just how good those high end offerings are.

--Rik

[Scarodactyl]

1. Will I be dissatisfied with sharpness and vignetting if I use the less expensive AmScope lens?

Probably. Particularly great amscope objectives are more the exception than the rule amd there will be a lot of variation.
If I wanted a head to head matchup for the Nikon in a new objective I'd go with this one.
https://bolioptics.com/objective-workin ... tive-10-a/
Maybe even made in the same factory since the nikon plans are made in china, though whether it would be equivalent to a nikon plan 10x, an e plan 10x or neither is an open question.

[JayMcClellan]

I own the AmScope A2X, PA4X and PA10X finite objectives. I don't (yet) own any higher-end objectives so I can't compare with the Nikon, but I can compare my results with these 3 AmScope objectives. The A2X and PA4X are very satisfactory in my experience. Although they're designed for a flange-to-image distance of 150mm, it is not critical and they also perform well with a distance down to about 100mm so I have a range of useful magnifications available. The A2X starts to vignette at that point even on a MFT sensor, but the PA4X does not. While not in the same league as a Nikon or Mitutoyo, they deliver surprisingly good images considering their under-$50 price tag.

A2X at about 1.5x magnification, slightly less than full frame:

PA4X at about 4x magnification, slightly less than full frame:

In my limited experience, the PA10X objective has high CA and low sharpness. Honestly I haven't spent a lot of time using it since the initial results were so disappointing, so perhaps I could figure out some way to get decent results with it, but even considering its low price I don't think it's a good value and I would recommend something better like one of the Nikon 10x objectives. To be fair, I did not spend much time on the following image so the quality could probably be improved with better lighting etc. but it will give you an idea of what to expect from this objective. I don't think it's worth owning.

PA10X at about 10x magnification, full frame:

[WojTek]

Hello Wbodine,

However, if you can afford to give up some working distance,
there is a less expensive Nikon objective that has very similar performance.
That is the Nikon CFI BE 10X NA 0.25 WD 6.7 (part number MRN70100, currently available HERE).

I started with NIKON CFI BE 4X and 10X.
Personally, I was impressed by their quality.

BTW, I was using a Canon EF 70-200L as a tube lens at the time.

Best, ADi