Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

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Chris S.
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Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by Chris S. »

Overview:

Here is a comparison between a Hoopuo 20x/0.45 objective, on loan from the lens maker, against my well-tested Mitutoyo 20x/0.42, on a camera with an APS-C-sized sensor. The Hoopuo struck me as very good--a bit better even than my Mitutoyo--which is saying something. The Hoopuo is much cheaper than the Mitutoyo, listed at $685 USD "dealer price"--compared with the Mitutoyo at $2175 USD.

If you're like me, you want to see the comparison photos before doing a lot of reading. But I do recommend reading the complete post, including things written after the image section. Please do this especially if you contemplate purchasing such an objective.


Information on test images:

Each image is an animated gif that switches between the Mitutoyo and Hoopnuo 20x every two seconds. Which lens you're seeing at the moment is marked.

Images are stacks processed with Zerene Stacker, PMax method.

Test target is laser print on white paper, glued to a microscope slide for flatness. Camera is a Nikon 24mp D7100 with an APS-C sensor. For emphasis, this sensor measures 23.5 x 15.6 mm--not the 36 x 24mm considered "full frame" for DSLRs.

The appearance of subject rotation is an illusion--in reality, nothing moved at all. The perceived movement is likely due to utilized aperture effects and differences in the lenses' telecentricity. Edit to add: Rik Littlefield, who is seldom wrong on such things, submits that some of the apparent movement in my test images—the global rotation—is likely real. Perhaps a 0.15 degree rotation. So a mechanical gremlin may have crept into my rig. If so, I’m going to have to root it out. (I do have a rather robust anti-rotation clamp fixing camera to tube lens, so the simplest explanation—lens-mount slop—is likely not the cause.

The specular reflections on the toner particles differ considerably in size, brightness, and shape between the two lenses. This is because these reflections come from light bouncing off the fronts of the objective barrels, and these barrels differ in construction. The Hoopnuo has a shiny barrel front; the Mitutoyo has a black front, plus a smaller shiny portion behind it.

To judge between the two objectives, you might take particular note of the black/white transitions at the edges of the toner particles.


Test images:


Full-frame view. Blue boxes indicate locations of "100 percent" crops shown afterward.
Both-20x-lenses,-full-frame--final.gif

Crop (Lower-right blue box)
Both-20x-lenses,-layered--lower-right-box.gif

Crop (Upper right blue box)
Both-20x-lenses,-layered--upper-right-box.gif

Crop (Near center blue box)
Both-20x-lenses,-layered--near-center-box.gif

Origin of this comparison:

This test grew out of an interesting thread by forum member Lothman (Lothar): How good are alternatives (clones) to Mitutoyo lenses. Lothar's tests and thread led to my being offered a couple Hoopuo objectives to test myself. The thread you're reading now was promised in Mitutoyo objective clones.

I'll avoid the term "Mitutoyo clone," in case it implies that Mitutoyo's optical formula has been copied. Such is likely not the case for Hoopuo lenses. As the maker communicated to me, Chinese glass types available to Hoopuo differ from the Japanese glass types available to Mitutoyo. If I understand correctly, this means that to get similar function to a Mitutoyo lens, Hoopuo had to design and execute an optical design around the glass elements it has available.

So I'll call the Hoopuo 20x a "Mitutoyo 20x workalike." This term has been in use by lens makers such as Optem and Edmund Optics, and denotes interoperability with Mitutoyo in microscopes and open photographic systems. For these uses, Mitutoyo objectives, with their 95mm parfocality, M26 x 36 TPI threads, and infinity-corrected optics, are one of the industry standards. Of course, whether or not a "workalike" lens is optically equal to a Mitutoyo is a question to be answered on a case-by-case basis.

The Hoopuo brand-name is interchangeable with another brand-name, "Southoptics." As explained to me, either nameplate is the same lens. The maker is Optronics Co., Ltd.

English-language Website
Chinese-language Website

Jerry, my contact (and Lothar's) at Hoopuo, may be reached at Opticsexpert@hotmail.com . Jerry has indicated that email is a very good way to contact him.

There have been Websites, such as this one, that have listed this and similar objectives from Hoopuo. Often, the products are listed as out of stock.


Caveat:

My sense is that Hoopuo earnestly wants to produce excellent optics for photomicrographers. Also, that they see this as a daunting task, given that photographers are demanding users, likely much harder to please than many users doing industrial tasks with these lenses. Hoopnuo asked me for time to develop and construct a lens for this test. So this lens was specifically built for my testing.

Consequently, I have no idea whether or not an objective ordered by anyone else will be as good.

Major lens makers such as Nikon and Canon have variable quality--sometimes the buyer gets a good one, sometimes a great one, sometimes a poor one. [For example, I recently sold my Micro-Nikkor 200mm f/4D IF-ED. While this is a highly-regarded model, my specimen was poor. I sent it to Nikon for adjustment, but they returned it unadjusted, saying it tested "within specification." (FYI, I sold it to a big company, as I was not willing to sell to another photographer, who would no-doubt have asked my opinion of the optic.)]

High-end optics involve a great deal of hand-assembly, with mixing and matching of glass elements to offset variation. (Yes, there is said to be a lot of variation between individual glass elements even from a single batch of glass.) I'm sure there is arcane measurement during this process. I've tested many Mitutoyo objectives, and have never seen two that rendered exactly alike. While undamaged specimens from Mitutoyo are all very good, one may have a bit more false color, but better contrast; another may have a bit less resolution in the center, but better resolution toward the edges. It's clear to me that during assembly, a human being is making adjustments, tradeoffs, and other decisions.

Hoopnuo has produced a very nice 20x/0.45 objective. But I have no ability to predict what level of sample variation may occur in other specimens. If there is interest, I'm tempted to order a few more such lenses, test them, and send them to buyers or return them to Hoopnuo as test results dictate.

If I do this, I effectively become an importer for Hoopnuo--something I think Jerry has suggested by email. (Saying "I think" because with the language difference, communication is not always crystal clear.) This will involve time and commitment, which I can't afford to do without charging something. Alternatively, one can of course buy directly from Jerry and do one's own testing. If anyone is interested in having me import and test a lens for you, PM or email me. As photomacrography.net is non-commercial, aspects involving a mark-up should probably best be discussed off-line.

--Chris S.

Scarodactyl
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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by Scarodactyl »

Thanks for the test! These are very impressive results even with the caveat in mind. Man, I'd love to try their 50x/0.65 and compare it with my current trio--it would be nice not to have to crank down to 45mm parfocal distances to go above 20x. Unfortunately I don't think the budget will allow for it any time soon, but at least the possibility it might give excellent results exists if they can make a 20x like this.

jurkovicovic
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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by jurkovicovic »

Hi, do you have any output from the Hoopuo 20x/0.45 for FF?
Thank you.
canon EOS *

wwheeler48
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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by wwheeler48 »

I am not in the market for another 20X objective, but I wanted to compliment you on an excellent job in comparing the two lenses and a very interesting discussion. Thanks.

lothman
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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by lothman »

Hello Chris,
thanks for your excellent test =D> I hope you forgive my impatience :mrgreen:
Chris S. wrote:
Sat Sep 17, 2022 8:50 pm
Caveat:
My sense is that Hoopuo earnestly wants to produce excellent optics for photomicrographers. Also, that they see this as a daunting task, given that photographers are demanding users, likely much harder to please than many users doing industrial tasks with these lenses. Hoopnuo asked me for time to develop and construct a lens for this test. So this lens was specifically built for my testing.
A lens with those specification was already listed when I did the test of the 10x. So do you thing "your" 20x differs in its optical design or was it meant to be of a careful manufactured batch?
Chris S. wrote:
Sat Sep 17, 2022 8:50 pm
Consequently, I have no idea whether or not an objective ordered by anyone else will be as good.
yes time will tell, at least I had two excellent 10x, the second ordered several months later for a friend. Bot were identical for me and much better than the 2 Mitus 10x I had access to. So this makes hope that they can maintain quality over time.

Chris S. wrote:
Sat Sep 17, 2022 8:50 pm
Hoopnuo has produced a very nice 20x/0.45 objective. But I have no ability to predict what level of sample variation may occur in other specimens. If there is interest, I'm tempted to order a few more such lenses, test them, and send them to buyers or return them to Hoopnuo as test results dictate.
I would be interested in a 50x lens if this is in the same league of the 20x and 10x. May be they improve the 5x but the two copies I had were weak.

Chris do you have plans to test the 50/0.65?

P.S.: by the way @Klavs when you read this, have you made further experience with your 50x/0.65?

Chris S.
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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by Chris S. »

Scarodactyl, Jurkovicovic, Wwheeler48, and Lothman, thanks for your feedback and comments!

Scarodactyl wrote:
Sat Sep 17, 2022 10:42 pm
. . . I'd love to try their 50x/0.65 . . . .
I also want to try the Hoopuo 50x/0.65. It is the objective I suggested testing first.

Jerry, at Hoopuo, preferred that we start testing with the 20x/0.45. This was okay with me. I have one other Hoopuo objective in hand to test. After that, I’ll ask Jerry about the 50x/0.65.

My strong sense is that most of Hoopuo’s market has, previously, been for industrial testing. And they feel that, to make objectives that work well for our far-less-tolerant photographic uses, they want to tread carefully, and if necessary, up their game as needed.

jurkovicovic wrote:
Sun Sep 18, 2022 2:00 am
. . . any output from the Hoopuo 20x/0.45 for FF?
Not at this time. I keep a dedicated APS-C camera hooked up in the macro studio, and use FF in the field—my thinking being that APS-C, on a 200mm tube lens, is a good match to the high-quality image circle of many objectives. This said, I know that others do care about FF performance with objectives.

When I did this test, my field camera was a 14-year old Nikon D700 (full frame, 12mp). Twelve megapixels, spread across a full-frame sensor, are two few, in my mind, to make very revealing crops. I very recently upgraded it to a Nikon Z7II—a FF camera with 46 megapixels. So I at least now have a camera that would do this well.

However, my macro rig was built for use with an APS-C sensor, and its tube lens vignettes on full frame. So I’d have to build or buy another tube lens. Then there is the need for an AC adapter, perhaps a different release cable, and maybe a different tethering cable to the computer. Ugh. And the through-the-eyepiece laser aiming/focus technique I find helpful won’t work with a mirrorless camera. Ugh again.

So I likely won’t do FF tests, unless several people who are seriously interested in this lens require it.

wwheeler48 wrote:
Sun Sep 18, 2022 8:14 am
I am not in the market for another 20X objective, but I wanted to compliment you on an excellent job in comparing the two lenses and a very interesting discussion. Thanks.
Thank you—I appreciate the tip o’ the hat!

lothman wrote:
Sun Sep 18, 2022 9:41 am
Thanks for your excellent test =D> I hope you forgive my impatience :mrgreen:
No problem, Lothar! I’ve appreciated the encouragement.
Chris S. wrote:
Sat Sep 17, 2022 8:50 pm
A lens with those specifications was already listed when I did the test of the 10x. So do you thing "your" 20x differs in its optical design or was it meant to be of a careful manufactured batch?
Very good question. I don’t know. My sense was that Hoopnuo was carefully looking at the lens design and thinking about the types of glass it has available, then doing whatever work was needed to produce a lens we photographers will love. Whether this work involved redesign or just careful quality control, I don’t know.

I do think that Hoopnuo wants what we want—excellent lenses at a more affordable price. If achieved, they’ll sell a lot of them, and we’ll buy a lot of them. Everybody wins.

My caveats amount to this: Building great lenses of the type we use--long working distance, high numerical aperture, low-level of aberrations--is really difficult. So let’s walk with care.

One update: Rik Littlefield, who is seldom wrong on such things, submits that some of the apparent movement in my test images—the global rotation—is likely real. Perhaps a 0.15 degree rotation. So a mechanical gremlin may have crept into my rig. If so, I’m going to have to root it out. (I do have a rather robust anti-rotation clamp fixing camera to tube lens, so the simplest explanation—lens-mount slop—is likely not the cause.

--Chris S.

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Re: Mitutoyo 20x/0.42 compared with workalike Hoopuo 20x/0.45

Post by chris_ma »

Chris S. wrote:
Tue Sep 20, 2022 9:34 pm
One update: Rik Littlefield, who is seldom wrong on such things, submits that some of the apparent movement in my test images—the global rotation—is likely real. Perhaps a 0.15 degree rotation. So a mechanical gremlin may have crept into my rig. If so, I’m going to have to root it out.
I agree, it also looked like a slight displacement rather then simply an optical effect due to lighting changes.

personally I don't work with anything higher then 2x mag, but I still enjoy reading well thought out comparisons like this, so thanks a lot for taking the time!
chris
chris

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