Mitutoyo Tube Lens MT-1 - Forward or Reverse for best IQ

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RobertOToole
Posts: 2627
Joined: Thu Jan 17, 2013 9:34 pm
Location: United States
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Mitutoyo Tube Lens MT-1 - Forward or Reverse for best IQ

Post by RobertOToole »

Finally finished tested the MT-1 both forward and reverse. As with the ITL200, and the Nikon MXA20696 lens, the MT-1 performs much better in reverse!

You can see more details on my site: https://www.closeuphotography.com/mitut ... tube-lens/

Thanks to Chris S for the loan!


The Lens:


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The Sigma LSA, with hazy elements removed and the MT-1 installed. The retainer ring hold the lens tightly and has M52 x 0.75 threads. I also use the LSA to hold other lenses, and to install the Raynox 170mm (I can post more on mounting the R170 if people are interested)

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Using the LSA you can mount the lens in normal and reverse!

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Mitutoyo set-up vs my recommended set-up

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Full 5x image with 100% crop area highlighted in blue.

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Left of Center crops, normal and reverse mount at 100% I see better sharpness and less CAs in reverse.

Note that all image corrections including NR are turned off in Photoshop. Also separate images were chosen for center, off-center and corner images so field curvature is not an issue here.

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

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Off-Center crops, normal and reverse mount at 100% Off-center the normal mount the sharper level is higher than reverse but the CAs are also higher.

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


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Corner crops, normal and reverse mount at 100% In the corner, normal mount is sharper but has more CAs.

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

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Conclusion

The center sharpness and CA correction is better in the center area when mounted in reverse, where the corner sharpness and CAs are higher when mounted normally. I would recommend reverse mounting.

Mitutoyo sells a non-APO corrected tube lens for use with their own APO corrected lenses. A better choice is the Thorlabs/Nikon ITL200 is 40% less costly and is APO corrected.

Test set-up notes:

Camera: Sony A6300
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 at Photoshop at 100% view. The single RAW file was 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.

Comments and questions welcome.

Robert
Last edited by RobertOToole on Sat Aug 11, 2018 10:50 am, edited 1 time in total.

RobertOToole
Posts: 2627
Joined: Thu Jan 17, 2013 9:34 pm
Location: United States
Contact:

Post by RobertOToole »

Forgot to mention that if you are interested in side by side comparison images of the ITL200/MT-1 reverse/Raynox 208mm/ Sigma LSA lenses, follow the site link:

https://www.closeuphotography.com/mitut ... tube-lens/

Thanks

Robert

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