www.photomacrography.net :: View topic - Testing dhmiller's 20x/0.55 Mitutoyo bargain lens from eBay
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Testing dhmiller's 20x/0.55 Mitutoyo bargain lens from eBay

 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions
View previous topic :: View next topic  
Author Message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3456
Location: Ohio, USA

PostPosted: Mon Dec 16, 2019 3:43 am    Post subject: Testing dhmiller's 20x/0.55 Mitutoyo bargain lens from eBay Reply with quote

Recently, dhmiller (Dennis) posted to ask if a bargain Mitutoyo 20x objective on eBay was "too good to be true." Price was $555 USD (new price would be $2055). Vendor photos showed scratches on the barrel and nicks in the black ring around the front glass. Such lenses can be bargains or junk, with no way to know which, other than by a hands-on test against a known benchmark. But the vendor permitted a return, and I offered to test. Here are some results.

The gif below gives a sense of the test--same target, same light, same everything for stacks comparing test lens and a known-good lens. Target is laser printed paper pasted to a microscope slide. Images are stacked to avoid influence of focus error or differences in field curvature, which doesn't matter much to focus stackers. There are black margins because the lenses' fields of view differ, and I wanted to show them aligned at center with no cropping.



The above gif is too small for serious evaluation. However, quick takeaways include:
    *At this level of scrutiny, quality of both lenses looks about the same
    *The lenses have different centers of view. Dennis' lens points a bit higher and to the left of mine. (This is repeatable, not a testing error. It's also quite normal among objectives.)
    *The two lenses have slightly different magnifications. (Also quite normal.)


Next is a gif cropped from just below center. Again, I'd caution against reading too much from this single, down-resolved comparison. Anyone wishing to do an evaluation is welcome to PM me for a Photoshop file with the original stacks presented as layers. I'd recommend zooming into the image in Photoshop (or similar software), and flashing the top (test lens) layer on and off (exposing the known lens) at a number of places around the frame. Doing so on these test files left me with the impression that my lens was a bit better in some places, and Dennis' lens a bit better in others. When the distribution of these better/worse impressions is random and about equal between lenses, and in no case is the test lens actually objectionable, I consider the lens to "pass." Since perception differs between people, I encourage the lens' buyer to repeat this scrutiny with his or her own eyes.



If the test lens passes the above and time permits, I like to do a quick stack of a real-world subject with the test lens. Some of us call this a pudding shot ("The proof of the pudding is in the eating.") So here is a quick pudding shot with Dennis' lens. Uncropped display of APS-C capture; field of view about 1.2mm wide:



100% crop (field of view about 0.2mm wide)


Dennis' bargain lens looks quite decent to me.


Notes:
    Camera: Nikon D7100 (APS-C sensor)
    Macro rig: Bratcam
    Lighting: Continuous halogen lights through fiber-optic light guides.
    All images acquired as jpegs; stacked with Zerene Stacker, PMax method; stacks saved as Tiff.
    Post: Pudding shots had curves adjustment; dust removal; small reduction in color as blue scale was initially rendered more vibrant than seen by my eye; and modest sharpening.

--Chris S.

--edited typos


Last edited by Chris S. on Tue Dec 17, 2019 12:26 am; edited 1 time in total
Back to top
View user's profile Send private message Send e-mail
Lou Jost



Joined: 04 Sep 2015
Posts: 4121
Location: Ecuador

PostPosted: Mon Dec 16, 2019 4:49 am    Post subject: Reply with quote

Congratulations to dhmiller, and a bottle of wine to Chris S!! Very generous of you to do this test.
_________________
Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com
Back to top
View user's profile Send private message Visit poster's website
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 8496
Location: Near London, UK

PostPosted: Mon Dec 16, 2019 7:12 am    Post subject: Reply with quote

Looks like a winner to me. Kudos again to Chris S, who has held my hand through the aquisition of much of a set of Mitties. "Our" combined total return rate would probably be around 40-50%, which is unluckier than average, I think.

The 50x I have is the chipped one Chris S tested. It's a little below par but not too much, and in the end was very cheap indeed.

One 7.5x came from the Far East, was well below expectations, and cost something around $60-70 to return, insured. Of course the vendor said it "didn't need" tracking. He would. wouldn't he, before he'd paid up? It took a couple of emails and a quote from Ebay Policies to get him to agree to pay for the correct postage. A short while after I got all moneys back, he put it on Ebay again, wiith no faults declared. I posted the serial number here.

Someone above (I can't see while posting) said that it's the vendor who specifies return conditions. Only to a point! If the item is only described as Used, then it has to be 100% working, with any significant matters described. When I've returnd things I've had no trouble beyond an email or two, getting money back. If you have a sharp picture of what you should get, and a fuzzy picture of what the lens produces, nobody can argue. If the vendor didn't say it was faulty, he has to take it back and pay postage. Sometimes I've known Ebay pay the postage, though.

I have a few protestations that "It was an "As-Is" " listing. There's no such thing! If the item is only described as "Used" in the vendor's description, then it should comply with Ebay's definition of that state, which you can quote. "Silosurplus "is a seller who uses the term a lot, so I'd avoid buying from him, though I know others have been lucky.

Some sellers definitely "try it on". My calendar's battery also goes flat from time to time, and I've found I haven't tested something until beyond ebay's rejection period. Mostly I've been OK, but not always. A new Mitty 20x is £1,746.75 in the UK - or $2050 in US. You have to take an overall view, sometimes!
_________________
Chris R
Back to top
View user's profile Send private message
dhmiller



Joined: 11 Nov 2019
Posts: 176

PostPosted: Mon Dec 16, 2019 7:27 am    Post subject: Reply with quote

;-)

Lou Jost wrote:
Congratulations to dhmiller, and a bottle of wine to Chris S!! Very generous of you to do this test.
Back to top
View user's profile Send private message Visit poster's website
dhmiller



Joined: 11 Nov 2019
Posts: 176

PostPosted: Mon Dec 16, 2019 7:43 am    Post subject: Reply with quote

Good info, Chris. I was concerned that this seller (Kliton) used the exact description and the exact reviews for all (dozens!) of his objectives at eBay.He also listed all of them as "Olympus"-just sloppy, I guess. But I had heard that he was a former forum member who posted good work, so I took the chance. Chris S took the concern out of the process by offering to test the Mity - kudos to him for sure.

ChrisR wrote:
Looks like a winner to me. Kudos again to Chris S, who has held my hand through the aquisition of much of a set of Mitties. "Our" combined total return rate would probably be around 40-50%, which is unluckier than average, I think.

The 50x I have is the chipped one Chris S tested. It's a little below par but not too much, and in the end was very cheap indeed.

One 7.5x came from the Far East, was well below expectations, and cost something around $60-70 to return, insured. Of course the vendor said it "didn't need" tracking. He would. wouldn't he, before he'd paid up? It took a couple of emails and a quote from Ebay Policies to get him to agree to pay for the correct postage. A short while after I got all moneys back, he put it on Ebay again, wiith no faults declared. I posted the serial number here.

Someone above (I can't see while posting) said that it's the vendor who specifies return conditions. Only to a point! If the item is only described as Used, then it has to be 100% working, with any significant matters described. When I've returnd things I've had no trouble beyond an email or two, getting money back. If you have a sharp picture of what you should get, and a fuzzy picture of what the lens produces, nobody can argue. If the vendor didn't say it was faulty, he has to take it back and pay postage. Sometimes I've known Ebay pay the postage, though.

I have a few protestations that "It was an "As-Is" " listing. There's no such thing! If the item is only described as "Used" in the vendor's description, then it should comply with Ebay's definition of that state, which you can quote. "Silosurplus "is a seller who uses the term a lot, so I'd avoid buying from him, though I know others have been lucky.

Some sellers definitely "try it on". My calendar's battery also goes flat from time to time, and I've found I haven't tested something until beyond ebay's rejection period. Mostly I've been OK, but not always. A new Mitty 20x is £1,746.75 in the UK - or $2050 in US. You have to take an overall view, sometimes!
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions All times are GMT - 7 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group