Mitutoyo blemishes... or inflated expectations?

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Sulafat
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Mitutoyo blemishes... or inflated expectations?

Post by Sulafat »

Hello,

Sorry for being long-winded in advance. I'm a relatively new extreme-macro enthusiast practicing my technique for roughly the past year or so. I started using microscope objectives soon after starting, yet many of their traits still remain mysteries to me.

I worked my way from a relatively inexpensive AmScope 10x finite lens to a relatively more expensive Nikon 10x infinite lens. I recently purchased a used Mitutoyo M Apo 10X on ebay from a long-term seller with a good rating. However, I worry I may have purchased a proverbial pig-in-a-poke. I'm looking for constructive opinions from any of the microscope objectives experts and other experienced users on this forum that will either provide reassurance that my objective is really OK and any perceived deficiencies lie with my technique, or the bitter truth that I purchased a flawed lens. I'll try to describe my suspicions.

I inspected the Miti upon receipt, and it looks by naked eye as it was described by the seller. I then set up a 150 image stack for a small fly using the Miti. (I used a reversed Raynox DCR 150 as tube lens focused to infinity mounted on a bellows with a M6MII. Light was provided by diffused speedlites.) I used Zerene Stacker Pmax with slabbing to process the stack. An unprocessed copy (other than "retouching" to remove stacking artifacts) of the output image is at the Flickr link below. I thought it looked pretty good, but not much better than images I created using the Nikon objective. I had expected a noticeable improvement with the Miti. Disappointment and paranoia set it...

https://flic.kr/p/2jLR7wD

I then took out my magnifying eyeglasses to take a closer look at the Miti. Looking at the external ends of the objective, both the nose and front external glass look very nice. No blemishes. However, there looks like a random, but wide-spread distribution of what appears to be dust motes on next internal lens element (i.e., the next one below the front external lens). I am surprised that an inner lens element would have such a wide-spread distribution of dust motes. I took some images parallel to the objective's center line along a radius (center, right middle, edge) showing samples of the motes. The FOV of the first three images is roughly 6mm (3.7x mag).

https://flic.kr/p/2jLS3r8
https://flic.kr/p/2jLS35M
https://flic.kr/p/2jLR8dy

Near the edge of the lens, in an anulus less than about 1mm width, I found what looked like small scratch lines, many ending with a dust mote. One blemish was exceptional, looking like meteor strikes on the moon. (Red circle highlights with blowup.) Luckily, that was the only one like that I saw.

https://flic.kr/p/2jLMzNT

Anyhow, are these phenomena common with Mitutoyo objectives? Maybe a by-product of manufacturing? Am I looking for problems that don't exist? Maybe I just have unrealistic expectations (or subliminal buyer's regret). As someone on this forum wisely noted, amateur photographers worry about equipment while master photographers worry about light. You know which one I am. Then again, this objective may be a pig in poke. Useful comments are invited. Thanks, Greg Brown.
Flickr page: https://flic.kr/ps/3eJvz5

I'm an amateur photographer in the gentle persuit of modest competency.

Lou Jost
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Lou Jost »

That's extraordinary damage. Nothing normal about it. I wonder if someone tried to disassemble and clean it...

Sym P. le
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Sym P. le »

Thank-you for having the courage to share your pain. The lens does not look like it is performing to it's potential and the internal damage/debris did not come from the factory. A reputable seller should not be pushing that lens without describing the obvious internal issues. I would try to return it. I damaged one of my objectives when I slipped and fell. Your fly image reminds me of my post fall images.

Chris S.
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Chris S. »

Greg,

I don't see anything in your documentation that would be an obvious cause of significant image degradation. Take a look, for example, at Mitutoyo 50x with chips in glass, tested. This said, even a cosmetically impeccable Mitutoyo objective can be an optical disaster.

Also, I wouldn't expect a Mitutoyo 10/0.28 to be an optical sea change from a good Nikon objective. The Mitty likely has more working distance, but it's in the higher-magnification ranges (20x and up) that Mitutoyo objectives really stand out optically from most competitors.

The only really effective way for you to evaluate your Mitty 10x is to have someone carefully compare it with a known-good Mitty 10x. I often do this as a favor to forum members, so PM me if I can help. (I'm in Ohio.) Be aware that I'm not especially good at hurrying, so if your return-privilege clock is running short, it might be best to simply return this lens.

--Chris S.

Lou Jost
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Lou Jost »

Chris, my take on that damage is that it indicates a bigger historical problem with this objective. The internal damage suggests someone opened it up, and it is impossible to put one of these back together without ruining it.

Chris S.
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Chris S. »

Lou,

Agreed that if this lens has been disassembled, it's junk. However, from the images Greg linked to, I'm not sure that anyone has disassembled this lens.

Looking into an objective can fool the eye (or at least my eyes)--things are not always in the location they appear to be. I wouldn't condemn this lens without a test, unless time does not permit.

Best,

--Chris S.

Lou Jost
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Joined: Fri Sep 04, 2015 7:03 am
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Lou Jost »

I just can't figure out how that damage could have happened to the internal surfaces of the optics unless the objective had been opened.

Sulafat
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Joined: Sun Jan 06, 2019 3:31 pm
Location: Tallahassee, FL, USA
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Re: Mitutoyo blemishes... or inflated expectations?

Post by Sulafat »

Hello,

Thanks everyone for sharing your comments and suggestions. Given my doubts, I decided to return the objective. The seller has accepted my return request with no debate. Proves that the quality of the seller is as important as the item for sell. Given my retentiveness and low threshold for risk, I've decided to save my pennies and get a new copy when the cash is at hand. That way, if I'm disappointed with my results, I will know who to blame. The good news is, since I'm a "man-of-a-certain-age," there might be a clean, lightly-used Miti for sale within a decade or so (optimistically) from my estate sale. Keep your eyes open. :-)

Thanks again,
Greg Brown
Flickr page: https://flic.kr/ps/3eJvz5

I'm an amateur photographer in the gentle persuit of modest competency.

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