Tube Lens Test With MITUTOYO 5X M Plan APO

[RobertOToole]

Since I am now back from the summer photo tours that I run every year I have decided, I am not really sure why, to start 5 big macro photo related projects at the same time. So for the last few weeks I have been just trying to catch up.

The good news is that I did finish up shooting a tube lens test comparing 19 lenses with a Mitutoyo 5x M Plan APO objective.

For the tube and close-up lenses I shot these forwards and reversed. For all the lenses I tested without any objective extension and with my normal 75 mm (3 inches) of extension on a Sony A-6300 body.

This is the full list:

Thorlabs ITL200 Tube Lens
Mitutoyo MT-1 Tube lens
Nikon MXA20696 Tube Lens
Reichert Microscope Tube Lens

Canon 250D Close-up Lens
Century Precision Optics +4 Achromatic Diopter Lens
Cosina MMA Matched Macro Adapter lens
Raynox DCR-150 / M-150 / Model CM-2000 1.5X / +4.8 diopter / 208mm lens
Raynox Macroscopic Lens 2X / CM-3500 6x / video 35x / +5.9 diopter / 170mm
Raynox DCR-250 / M-250 / Model CM-2000 2.5X / +8 diopter / 125mm lens
Sigma LSA Life Size Attachment lens

Asahi  Pentax Tele-Takumar 200mm f/5.6 lens
Carl Zeiss Tele-Tessar T* 200mm f/3.5 lens
Nikkor 135mm f/3.5 Ai lens
Nikkor 200mm f/4 Ai lens
Olympus F-Zuiko AUTO-T 200mm f/5.0 lens
Sigma 150mm F2.8 EX DG OS HSM APO Macro lens
Voigtlander APO-Lanthar 125mm f/2.5 SL lens


This weekend I spent a few hours working on processing images for part one of the comparison. This post will cover part one with results from seven 200 mm lenses and split into two parts:

Thorlabs ITL200 Tube Lens
Nikkor 200mm f/4 Ai Lens
Asahi Pentax Tele-Takumar 200mm f/5.6
Carl Zeiss Tele-Tessar T* 200mm f/3.5


Thorlabs ITL200 Tube Lens
Mitutoyo MT-1 Tube Lens
Raynox DCR-150 / Model CM-2000 1.5X / +4.8 diopter / 208mm Lens
Sigma LSA Life Size Attachment






There were a few surprises in the first part of the test.

Most of the lenses are pretty similar in the center of the frame, so the test results really point out what lens introduce the least amount of chromatic aberrations and corner softness.

The Thorlabs and the Raynox +4.8 lenses were easily the best performers with impressive chromatic aberration control. The Raynox introduced some mild field curvature, the ITL200 image remained flat.

The Thorlabs ITL200 tube lens, made by Nikon, looks very similar to the Nikon MXA20696 lens (just received one today) but the performance is not!

The Thorlabs ITL200 should not be set up as Thorlabs recommends. Using the official set-up numbers, the lens performance was below average and near the rear of the group. But setup properly, it was the best in the comparison. See more info on the set-ups with sample images.


These are the results from part one of the tube lens test. You can see more about the test results and more details about the ITL200 on my site: https://www.closeuphotography.com/thorlabs-itl200/

Thorlabs ITL200 Tube Lens
Nikkor 200mm f/4 Ai Lens
Asahi Pentax Tele-Takumar 200mm f/5.6
Carl Zeiss Tele-Tessar T* 200mm f/3.5


Notes, the ITL200 was mounted in reverse (small side towards the objective) with 75mm of space between the lens and objective. The telephoto lenses were shot wide-open with no space between the lens and objective.

Un-cropped image with 100% crop highlighted in blue



100% center crops
Click on any image below to launch a new window with a larger 2500 pixel version. You can right click, or two-finger click with a Mac and select the open in a new tab or new window options.



In the center all of these lenses are sharp but with the full size 2500 px JPEG view, you can see chromatic aberrations with the telephoto lenses.

100% off center crops


Same results as the center, all of these lenses are sharp, but the red fringing with the telephoto lenses is even worse

100% corner crops


All of the telephotos see a big drop in image quality in the corners on an APS-C sensor. The ITL200 is consistent and almost perfectly CA free across the frame.
The center, off center and corners crops images are from different frames if the lens introduced any field curvature. The ITL200 did not.

Thorlabs ITL200 Tube Lens
Mitutoyo MT-1 Tube Lens
Raynox DCR-150 / Model CM-2000 1.5X / +4.8 diopter / 208mm Lens
Sigma LSA Life Size Attachment

Notes, the ITL200 was mounted in reverse (small side towards the objective) with 75mm of space between the lens and objective. The other lenses were shot with with 75mm of space between the lens and objective.

Click on any image below to launch a new window with a larger 2500 pixel version. You can right click, or two-finger click with a Mac and select the open in a new tab or new window options.

100% center crops


The Thorlabs and Raynox as best in the center, the Mitutoyo and Raynox show some lateral CA issues.

100% off center crops


Off center all of the lenses are very sharp and show very nice detail at 100%. Lateral CAs are a problem for the MT-1 and Sigma.

100% corner crops


In the corner the Mitutoyo MT-1 and Sigma LSA lateral CA issues disappear. The Raynox corner does show a drop off in image quality. The ITL200 is near perfect in the corners.

Test Set-up:

Camera: Sony A6300, ILCE-6300
Sensor size: 23.5 × 15.6 mm. APS-C. 28.21 mm diagonal. 3.92 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block

A series of images was shot with each lens in 10 micron steps, and the sharpest image was chosen for center, edge, and corner Photoshop at 100% actual pixel view. All images were shot as a single RAW files and processed in PS CC with all noise reduction and lens correction turned off, all settings were zeroed out (true zero) and the same settings were used for all of the images. All of the images shown here are single files.

Special thanks for Chris S for the MT-1 and ITL200 loaners as this would not have been possible without the help. Thanks Chris!


Questions and comments welcome.

Thanks for looking

Robert

[RobertOToole]

Update:

Just received a Nikon MXA20696 tube lens today and took some test images already. I will create a post for this lens when I get a chance to finish processing images.

The MXA20696 looks almost identical to the Thorlabs ITL200 but they performance is not the same!

Thanks for looking.

Robert

[AlxndrBrg]

Tremendous work as always!

I'm surprised the "in-house" tube lens by Mitutoyo looks so poor, considering the quality of their lenses.
Or is it just me that imagine things? The centre crop has low contrast and looks a lot less sharp than the others, but the off-centre and corner crops get progressively more similar to the competitors.

Is there maybe some internal reflections in the tube lens that lowers the contrast?

[Beatsy]

Robert, you are an absolute gem! The timing of this series of tests is uncanny. After experiencing the perfect flat fields of scanner lenses (prompted by and thanks to you), the comparatively less-than-stellar performance of my Mitties in this regard has become irksome. It is obviously something lacking in tube lenses and/or the setup. So I started fiddling with lenses and configurations looking for better performance. Forever optimising. This series of tests couldn't have come at a better time (before I spent money on my new quest) and will save me no end of frustration from running up blind alleys. I'm very much looking forward to the conclusions!! Thanks yet again.

[RobertOToole]

Tremendous work as always!

I'm surprised the "in-house" tube lens by Mitutoyo looks so poor, considering the quality of their lenses.
Or is it just me that imagine things? The centre crop has low contrast and looks a lot less sharp than the others, but the off-centre and corner crops get progressively more similar to the competitors.

Is there maybe some internal reflections in the tube lens that lowers the contrast?

Thanks for the comment.

The softness and lack of contrast on the MT-1 is disappointing, but I think the CAs are the biggest disappointment.

A couple of notes.

The MT-1 inner barrel is shiny and is not flocked. All of the SM2 tubes in the set-up are flocked.

The MT-1 is one of 3 visible wavelength tube lenses offered my Mitutoyo. Maybe another tube is more suitable?



I set the MT-1 according to Mitutoyos diagram. This is one of the only lenses that I did not try in reverse. I wonder if that would improve the results?

The Thorlabs set-up information listed on their site is wrong. I found this out in testing. I could try my own set-up on the MT-1 also.

[RobertOToole]

Robert, you are an absolute gem! The timing of this series of tests is uncanny. After experiencing the perfect flat fields of scanner lenses (prompted by and thanks to you), the comparatively less-than-stellar performance of my Mitties in this regard has become irksome. It is obviously something lacking in tube lenses and/or the setup. So I started fiddling with lenses and configurations looking for better performance. Forever optimising. This series of tests couldn't have come at a better time (before I spent money on my new quest) and will save me no end of frustration from running up blind alleys. I'm very much looking forward to the conclusions!! Thanks yet again.

Glad to hear you find the info useful Beatsy, I was hoping someone would find it useful.

I spent way more time on this than expected. Hour after hour and then a few more hours but the results made it all worth it.

I hoped this information would save people some time, not to mention the 100s and 100s of dollars I spent buying a ton of tube lenses over the a last couple of years.

The lower focal length lens results are really interesting also BTW. Now I need to get working setting up that info.

All the best,

Robert

[mawyatt]

Robert,

I find all your work on this and other lens evaluations extremely valuable. Your test setup & subject is an ideal platform for some informative results and benefits us all

So hats off to you for this and other efforts to show actuals rather speculation

Anxiously waiting to see your other results.

Best,

[rjlittlefield]

The MT-1 inner barrel is shiny

This issue can be mitigated by putting a circular mask just in front of the MT-1, with a hole that is barely large enough to pass all the intended imaging rays (i.e., no vignetting). In this position, it roughly plays the equivalent of a field stop in microscopy, blocking light from outside the FOV that would otherwise cause stray reflections and veiling glare.

Alternatively, place a mask behind the MT-1, so that the sensor cannot see the sides of the barrel.

I use the same trick in my Raynox setups.

--Rik

[RobertOToole]

This is interesting.

Decided to flip the MT-1 around just now, the reverse of what the Mitutoyo set-up diagram has.

Shot one image and CAs are gone and contrast is up but there is a lot of field curvature.

Need to run out for JiuJitsu training now but I can run a full image stack when I get back.

Robert

[ChrisR]

This is valuable stuff, Robert. Other than by mistake, I wonder how long it would have been before someone else tested a reversed manufacturer's tube lens.
The Thorlabs diagram is from Nikon ish - the numbers are slightly different. Perhaps that's the non-apo version and someone though it would be the same setup - ish..
If you look at the CAD drawings for the ITL200 on Thorlabs site (not the pdf) it says Nikon lens...

[RobertOToole]

This is valuable stuff, Robert. Other than by mistake, I wonder how long it would have been before someone else tested a reversed manufacturer's tube lens.
The Thorlabs diagram is from Nikon ish - the numbers are slightly different. Perhaps that's the non-apo version and someone though it would be the same setup - ish..
If you look at the CAD drawings for the ITL200 on Thorlabs site (not the pdf) it says Nikon lens...

I have to say thanks to Chris S for loaning me the lenses in the first place.

Since the ITL200 re-test images I bought a ITL200 and the Thorlabs adapter

[RobertOToole]

Its official!

Mounting the MT-1 in reverse and set up for infinity focus, 99% of the lateral CAs are gone and the contrast way up.

I ran a full series, there is quite a bit of field curvature, a lot more than even the Raynox 208mm.

Will post something as soon as I get a chance.

First I have lunch date with the wife.

Robert

[ChrisR]

I think "nonplussed" is the word.

[Lou Jost]

Thanks for this, Robert. Very valuable work!!! I bought the $169 version as a result.

I also accidentally have Nikon and Olympus tube lenses in some epi-lighting attachments I bought. Will try to test them one of these days....

[ChrisR]

Reminder:
Adapter
http://www.photomacrography.net/forum/v ... 128#209128