Counterfeit Mitutoyo Objectives?

[cube-tube]

Are counterfeit Mitutoyo objectives a concern?
I have noticed minor differences between used Mitutoyo objectives, mostly that some of them have red text, while new objectives have all black text.

Here is a genuine 20x:


This one doesn't look too bad:


This one is a bit strange:


This one looks absolutely horrible:



Are some, or all, of these objectives counterfeit?
Thanks

[enricosavazzi]

The ones with the red engraved text or mixed red and black are older M Plan Apo series. There have been several series. I don't know how many, but if you search this site you can find examples of older and newer series. The different series can differ in several details of barrel appearance.

The last two of your pictures do not show an M Plan Apo, or at least I don't recognize it as such (I have a few, and have seen many more). It must be a different type of objective, perhaps for transmitted illumination. It might have a spring-loaded retracting nose, which would suggest a short working distance. The data on the barrel, not visible in your pictures, would tell more.

I am not aware of any counterfeit Mitutoyo objective, but as eBay has been vacuumed of most genuine Mitutoyo objectives (at least those in good conditions and offered at reasonable prices), it is not impossible that someone, sooner or later, will try to push other objectives as Mitutoyos, perhaps even going to the length of engraving them with the Mitutoyo brand. However, this is for sure going to destroy the seller's reputation, so I don't think an established seller will do it. If any easily identifiable counterfeits are going to appear, they will probably be offered by a seller with little or no feedback.

[cube-tube]

Thank you so much enricosavazzi! I just bought one of the Mitutoyos with red text at a suspiciously low price, but maybe I just got lucky.

[Macrero]

There are Mitutoyo "clones", but I've never seen/heard of any counterfeited Mitutoyo objectives.

As Enrico mentioned, the first ones are earlier versions of the M Plan Apo. The last one is genuine Mitutoyo objective too, but intended for hardness testing machines, not a good choice for microphotography. I don't think it looks horrible though, it looks just like... microscope objective

Best,

- Macrero

[rjlittlefield]

cube-tube, to clarify...

"Clone" means an objective with the same general appearance and same nominal specifications, but with brand labeling that is completely different or missing, not intended or likely to mislead, clearly not "Mitutoyo" or anything similar.

For example http://www.bwoptics.com/proend.asp?id=92 shows a line of objectives that look, act, and are labeled using the same terms as Mitutoyo's M Plan Apo series, except that they don't say "Mitutoyo".

These particular objectives are not quite clones because their working distances are different than the corresponding Mitutoyo's, but they're close enough to illustrate the idea.

--Rik

[Pau]

For example http://www.bwoptics.com/proend.asp?id=92

Curiously their M Plan UV 80X has specially poor transmission in the near UV

[rjlittlefield]

For example http://www.bwoptics.com/proend.asp?id=92

Curiously their M Plan UV 80X has specially poor transmission in the near UV

Even more curious, the bwoptics.com graph of transmission appears to be an exact copy of the graph shown by Edmund Optics for Mitutoyo: https://www.edmundoptics.eu/microscopy/ ... bjectives/ , scroll to Technical Images section. The .gif files are binary identical. In this aspect, I suspect that something less than perfectly honest is going on.

Links to images are
https://www.edmundoptics.eu/globalasset ... n_char.gif
http://www.bwoptics.com/html/UploadFile ... 516292.gif

--Rik

[Pau]

Good catch!
...and a complementary proof of the crime is that BW doesn't have any 80UV in his catalog while Mitutoyo does.

[Chris S.]

This one is a bit strange:

It looks strange because it isn't a Mitutoyo. If this image came from eBay auction 263209804280, the seller does say "Mitutoyo", which is apt to mislead buyers.

Clues include the numerical aperture of 0.40 (the most commonly used Mitutoyo 20x has an NA of 0.42). Also the designation as "SLWD" (meaning "super long working distance"; the Mitutoyo objectives most of us use are "LWD" without the "super"; Mitutoyo does have a line of SLWD optics, but their NA's are smaller (delivering less resolution), and they are marked with a double ring (green in this case), whereas this objective has a single green ring.

Based on a short search, this appears to be a Seiwa Optical objective.

As others have said, counterfeit Mitutoyo's do not seem to be an issue. (I've had dozens of second-hand objectives pass through my hands, without ever seeing a counterfeit.) However, various manufacturers have made objectives that look like Mitutoyo's, and have the same threads and parfocal distance. They call these "workalikes" because they can be used in the same microscopes. Whether or not these lenses really do work like Mitutoyo objectives is variable. The best of them may come somewhere in the neighborhood (at prices that are also somewhat close to Mitutoyo). The worst are quite awful (I've tested some of these.)

--Chris S.

[Macrero]

This one is a bit strange:

It looks strange because it isn't a Mitutoyo. If this image came from eBay auction 263209804280, the seller does say "Mitutoyo", which is apt to mislead buyers.

Nice catch, that one is a Correct (made by Seiwa Optical) objective. The "Mitutoyo" in the title is obviously misleading...

[enricosavazzi]

For example http://www.bwoptics.com/proend.asp?id=92

Curiously their M Plan UV 80X has specially poor transmission in the near UV

It seems this is the data from actual Mitutoyo objectives.

In this case, there is a good explanation why the M Plan UV 80x performs poorly in the NUV. There are two series of Mitutoyo M Plan designed for UV work:

• - The Mitutoyo M Plan Apo NUV are designed for use in the near-UV (roughly 320-400 nm) and VIS.
  - The Mitutoyo M Plan UV series, instead, is designed for use with excimer UV lasers (roughly 250 nm) and VIS, so their performance in NUV is irrelevant.

[cube-tube]

Thanks for the info guys! Very interesting.

[Marsman]

I just purchased the same lens in the last two images in this thread. I convinced the guy to give me a very low price since it looked like a Mitutoyo, but had the name "Correct" stamped on it. Considered for a moment it was a counterfeit clone of the Mitutoyo. However, as others have previously identified, it's made by a reputable Japanese optics company called "Seiwa" AKA "Correct". It has almost identical specs as the Mitutoyo 20X with an NA of 0.40 rather than Mitutoyo's 20X NA of 0.42. It has slightly longer WD, which might account for the small difference. It was taken off a machine in the computer chip business that uses both Mitutoyo and Seiwa, so it's a high quality lens. One I suspect that's on the same playing field as the Mitutoyos. If you get a screaming deal on one, I would go for it if you're trying to get the best bang for the buck.

[Scarodactyl]

I have wondered about the Seiwa objectives. One got a poor review here in the past, but they do have a long history and significant presence in the market, so it would be hasty to judge them from one example. I hope you'll post a review when it comes in, both of image quality and coverage.

[kiennosuke]

https://www.ebay.com/itm/MITUTOYO-810-6 ... 0290.m3507