How good are alternatives (clones) to Mitutoyo lenses

[Scarodactyl]

For testing performance on this sort of objective you need some high contrast, high detail area in the corners. Some subjects are extremely forgiving on CA and distortion and will mask weaknesses in imaging.

[Barrelcactusaddict]

I recently got a x10 from a member of this forum that is exact to the photo you post (well, the photo shows 0.30 and mine is 0.28) and, although I may not be very demanding about the results, I'm excited about the results. I'm thinking of changing the rest my lens now ...
If what I know about astronomy can be extrapolated, it is difficult to know what who does in China.

It is one of the first tests.

Now that's a nice specimen! Almost looks like a Greek brochantite to me, but I could be wrong.

It seems that particular objective works quite well as a "metallurgical-type" (what with such a mineral specimen being reflective and opaque), and not just primarily as a "biological-type" objective.

Very nice!

[soldevilla]

Now that's a nice specimen! Almost looks like a Greek brochantite to me, but I could be wrong.

very near... Brochantite, but from Spain

[DavyC]

My spidey-senses are tingling. I am getting a bad feeling about this.
Clone on the outside, but a few faulty genes on the inside.
Hope I am wrong though.
I do like a bargain

[Barrelcactusaddict]

very near... Brochantite, but from Spain

Nice! At least I got the mineral species correct, haha; my interest in amber has gotten me a bit rusty with mineral collection and identification.

I do love a good micromount specimen; it's so much easier to find perfect crystals that way!

[Barrelcactusaddict]

My spidey-senses are tingling. I am getting a bad feeling about this.
Clone on the outside, but a few faulty genes on the inside.
Hope I am wrong though.
I do like a bargain

I agree; my first impression is the same, when it comes to brand imitations. Hopefully, the objectives' faulty genes are a positive mutation!

[mjkzz]

I got a Chinese "clone" that looks just like what is shown in previous posts -- 5X APO 0.15NA. The one on the left is the "clone" and the one on the right is the genuine Mitty MPlan 5x APO 0.14NA. But the "clone" was pretty bad. However, I have to say that was LONG time ago and things might have changed.

FWIW, just because I was testing a Mitty 5x on 100mm tube lens vs Mitty QV 2.5x, I just ran a test between a genuine Mitty 5x and a "clone". I kept all conditions the same, just changing the objective.

First of all, just by looking at the final images, the Mitty 5x produces brighter images and it has NA of 0.14 vs "clone"'s 0.15, so something is wrong here.

Mitty 5x on 100mm tube lens

"clone" on 100mm tube lens

Mitty 5x does not seem to create any CA at all

Obvious CA with the "clone"

If you are interested, here are all the images used for above comparisons. The first 214 images were done with the "clone" and the 2nd 214 images were done with genuine Mitty, on 100mm tube lens. https://www.dropbox.com/s/xxldemwkmbbo3 ... e.zip?dl=0

[mjkzz]

also, the genuine Mitty seems to produce much sharper images and more details (take a look at the shiny triangle part)

[Barrelcactusaddict]

I got a Chinese "clone" that looks just like what is shown in previous posts -- 5X APO 0.15NA. The one on the left is the "clone" and the one on the right is the genuine Mitty MPlan 5x APO 0.14NA. But the "clone" was pretty bad. However, I have to say that was LONG time ago and things might have changed.
MvsC.jpg

FWIW, just because I was testing a Mitty 5x on 100mm tube lens vs Mitty QV 2.5x, I just ran a test between a genuine Mitty 5x and a "clone". I kept all conditions the same, just changing the objective.

First of all, just by looking at the final images, the Mitty 5x produces brighter images and it has NA of 0.14 vs "clone"'s 0.15, so something is wrong here.

...

If you are interested, here are all the images used for above comparisons. The first 214 images were done with the "clone" and the 2nd 214 images were done with genuine Mitty, on 100mm tube lens. https://www.dropbox.com/s/xxldemwkmbbo3 ... e.zip?dl=0

Thank you for sharing those comparisons, they are very helpful!

It's strange that the dimensions of the clone are not exact to that of the Mitutoyo; I wonder if this might be the case with the newest versions of the clone (I can't seem to find any other pics of a Mitutoyo next to the newest clone). The clone's barrel length is noticeably shorter, but it still has a focal length of 200mm (assuming that's correct), so maybe the Mitutoyo has a bit more empty space? I wonder if the clone had been disassembled at some point before you purchased it; or maybe the internal glass is not as of high a quality. You're right, there's something wrong there.

I hope the newest clones improved on their old design; btw, do you happen to know approximately when that clone was manufactured?

[Scarodactyl]

This is an interesting comparison! I appreciate you putting up the source files. I took a look at them since I had another question I was wondering about--while the images provided already firmly nail down that the Mitutoyo does much, much better on a 100mm tube lens, the clone is only specced for 24mm of coverage on a 200mm tube lens (to cover the eyepieces on a Chinese finescope clone), and I wondered if it might be possible that within that spec it performs acceptably. I have tried a Seiwa 10x which performed surprisingly well on aps-c, just about the same as my real mitutoyo, so there is definitely the possibility fo lenses with lesser coverage still having admirable performance within their limits.

From what I can tell, this clone absolutely does not. The image on the clone is pretty strongly distorted relative to the mitutoyo--even at the very center it isn't as sharp, and the image rapidly gets mushy moving out from the center in addition to the CA. Even on a 1/2.3" sensor with a 200mm tube lens you would notice the Mitutoyo is better. If this isn't a particularly bad copy then these are pretty hopeless. Hopefully the newer designs are better, but they'd have a lot of room for improvement before they came close to giving Mitutoyo a run for their money.

Thanks again for posting this, your previously posted test was about the only firm data point available about this clone but it had left me with the question of coverage which you have handily answered.

[mjkzz]

I hope the newest clones improved on their old design; btw, do you happen to know approximately when that clone was manufactured?

No, I do not know when it is made, but I got it quite long ago, maybe 2017? I actually wrote a post about it a year later here. Initially, the first copy they sent to me was labelled as 0.14NA, but it had a lot of CA, so I exchanged it, the 2nd copy had even more CA, so I complained. So they said, pretty proudly, they were going to UPGRADE me to one with 0.15NA and this is the one shown here. It has less CA, but as you can see, still visible. Since it is shiny and I need something looking cool as prop in videos, so I kept it (and the exchange period expired).

From the way they talked to me, it seems this was a new product, when it came, the shell was loose with finger prints on the front element, suggesting it might even be an engineering copy.

Newer one might be much better because things in China change soooo fast. However, as far as I know, to correct the CA, it is not just the shape, arrangement of lenses inside, it is also the ingredient that lenses are made of, that part is hard to reverse engineer.

[mjkzz]

ah, I wrote this blog post in April 2017, that was at least a year later as some people was asking about it, so I wrote a general post on how to check CA. That means, I got the copy back in midlle of 2016, quite long time ago.

Note, in the blog, I used a 135mm lens for the QV and the "clone", 200mm for the 4X generic cheap objective.

https://pylin.com/2017/04/27/checking-m ... berration/

[mjkzz]

It seems the front element of a real Mitty is much larger than that of the "clone". Given the formula of NA, I am willing to guess that the NA of 0.15 etched on the "clone" is bogus. Of course, this is not a real scientific way of doing it, but practically, my willingness comes from the fact the real Mitty produces brighter image.

The one on the left is the "clone".

[Barrelcactusaddict]

It seems the front element of a real Mitty is much larger than that of the "clone". Given the formula of NA, I am willing to guess that the NA of 0.15 etched on the "clone" is bogus. Of course, this is not a real scientific way of doing it, but practically, my willingness comes from the fact the real Mitty produces brighter image.

The one on the left is the "clone".
clonevsmitty.jpg

I'd agree with that determination; I'm surprised at how considerable the difference in diameter is, between the two objectives' optics. Comparing your clone to the 5x objective in the original post's link, it appears that not much has changed in regards to the diameter of the objective's optics.

With all those blemishes (I'd assume they're scratches) on the lens of the Mitutoyo objective, I'm amazed at how clear the images came out! Perhaps I shouldn't worry so much about defects to the lens surface when considering purchasing a used objective.

[mjkzz]

It seems the front element of a real Mitty is much larger than that of the "clone". Given the formula of NA, I am willing to guess that the NA of 0.15 etched on the "clone" is bogus. Of course, this is not a real scientific way of doing it, but practically, my willingness comes from the fact the real Mitty produces brighter image.

The one on the left is the "clone".
clonevsmitty.jpg

I'd agree with that determination; I'm surprised at how considerable the difference in diameter is, between the two objectives' optics.

With all those blemishes (I'd assume they're scratches) on the lens of the Mitutoyo objective, I'm amazed at how clear the images came out! Perhaps I shouldn't worry so much about defects to the lens surface when considering purchasing a used objective.

yes, there are a lot of scratches on the real mitty, some are severe to be classified as ding that looks like it ran into some sharp object. I got that one from a factory automation auction and you know how it is in a factory, and it has been dropped a few time by me, yet it still performs well in my opinion