Tube Lens Test 2018

Tube-lens-ray-trace.jpg

What is a Tube Lens?

To use an infinity-corrected objective for photography, you will need a tube lens in addition to the main objective, or the system will not focus, since the tube lens is a required part of a infinity-corrected optical system. The tube lens can be a telephoto lens, a close-up diopter, or a tube lenses designed for a microscope.

To find out if you need to use a tube lens with an objective, it's easy to check, infinity-corrected objectives are identified with the infinite mark () on the side of the lens barrel. 

The magnification obtained by an infinity-corrected objective is the ratio between the focal length of the tube Lens and the objective. The most common tube lens focal length used by Mitutoyo and most other manufacturers is 200mm.  With infinity-corrected objectives you can change the tube lens focal length to create different magnification ratios at the camera sensor, without compromising the color correction. To calculate the system magnification for different tube lens and objective combinations, you can use this simple formula; Effective magnification = Marked magnification x the new tube lens focal length / the system tube lens focal length

the Lenses in this test

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
Century Precision Optics +7 Achromatic Diopter Lens
Cosina MMA Matched Macro Adapter Lens
Raynox +4.8 diopter
Raynox +5.9 diopter
Raynox +8 diopter
Sigma LSA Life Size Attachment Lens

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

The Test Set-up

The Mitutoyo 5x M Plan APO was for this comparison since it's one of the most popular objectives used for photography, and thanks to the objective's sharp flat field and excellent chromatic aberration correction, any aberrations introduced by the tube lens would be easily noticable. In addition to being infinity-corrected, Mitutoyo objectives are completely corrected in the objective so they do not need any tube lens correction. 

A series of images was shot with each lens in 5 micron steps, and the sharpest image was chosen for center, off-center, and corner using 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.

The Equipment

Objective: Mitutoyo 5x M Plan APO
Camera: Sony α6300, model ILCE-6300, also known as the A6300
Sensor size: 23.5 × 15.6 mm. APS-C. 28.21 mm diagonal. 3.92 micron sensor pitch
Flash: two Godox TT350s wireless flash units, one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block

How to Compare Test Results side-by-side

  • Right click, or two-finger press any image, and select Open in a New Tab or New Window from the menu, you can repeat this to open as many new images as you would like to compare.
  • Right click, or two-finger press any image, and select  Save Image As.. Save and repeat. Compare images with an image viewer of your choice. I use Photo Mechanic: http://www.camerabits.com/

200 mm test results

Thorlabs ITL200

https://www.closeuphotography.com/thorlabs-itl200/

Set-up:

  • Infinity focus
  • Reverse mount
  • 75mm from tube lens to objective

Image Quality:

  • Overall: 9.3 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 10

Mounting: The ITL200 comes with 38mm x 0.50 threads but the lens couldn't be easier to install with the optional Thorlabs tube lens adapter equipped with 52mm x 0.75 threads. Reverse mount with threaded section or the larger end towards the sensor. See the ITL200 webpage for more details.

Test Notes:

  • Setup with this lens is very easy with the Thorlabs 52mm x 0.75/SM2 tube lens adapter.
  • Using the official Thorlabs set-up guidelines will result in a performance drop.
  • 3 different samples of this lens were tested.
  • This lens was tested in 7 different configurations, some of these, especially with shorter extension were excellent. Examples of the other set-ups is available here on Closeuphotography.com:

    https://www.closeuphotography.com/thorlabs-itl200/

Raynox 208 MM (43mm mount)

Also know as: DCR-150, Macroscopic Lens Model M-150, Model CM-2000 1.5X, +4.8 diopter

www.closeuphotography.com/raynox-tube-lens

Set-up:

  • Infinity focus
  • Normal mount
  • 50mm from tube lens to objective

Image Quality:

  • Overall: 8 out of 10
  • Center: 8 
  • Corner: 8 
  • Chromatic Aberration Control: 9

Mounting: Thanks to 43mm x 0.5 and 49mm x 0.5 threads this lens is easy to install once you purchase the necessary step-down adapters.

Test Notes:

  • Some field curvature introduced, field not as flat as ITL200 or Century lenses.
  • Short focus (less extension) results in less magnification, better sharpness and less CAs, see the results below.
  • Reverse mounting results in better corners but worse in the center.
  • 3 different samples of the this lens were tested.
  • This lens was tested in 9 different configurations, some of these, especially those with shorter extension, were excellent. Examples of the other set-ups is available here on Closeuphotography.com: Closeuphotography.com/raynox-tube-lens

 

Century Precision Optics +4 Achromatic Diopter Lens

Set-up:

  • Short focus, 166 mm extension from sensor to lens
  • Normal mount
  • 110mm extension from tube lens to objective

Image Quality:

  • Overall: 9 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 8.5

Mounting: This lens uses common 58mm x 0.75 threads front and rear so it's easy to install with easy to find 58mm x 0.5 step-down adapters.

Test Notes:

  • Completely flat field, no field curvature.
  • Slightly sharper in the center than the Raynox 200.
  • Short focus produces better results than infinity focus.
  • Short focus, or using a lens with less extension than is needed for infinity focus means that it is "focused" beyond infinity. This would create an unusable blurry image, but in many cases this happens to work well with tube lenses - as described here. Short focus results in shorter "effective focal length" used here for magnification calculation purposes, so for example the Century +4, 250mm lens, with short focus is a 206mm effective FL lens, this would give you 1.01 x the Mitutoyo objectives marked magnification, for the Mitutoyo 5x M Plan lens this would be 5.08x.
  • Lens performs better with 50-110mm extension from tube lens to objective, minimal extension resulted in slightly more CAs.
  • With lens mounted normally corners were slightly sharper and field was flatter than when reverse mounted. 
  • Compared to a down-sized normal focus image, the pushed down/short focus image is sharper, clean and more detailed.

Mitutoyo MT-1 Tube lens

https://www.closeuphotography.com/mitutoyo-mt-1-tube-lens/

Set-up:

  • Infinity focus - 245 mm of extension from sensor to tube lens 
  • Reverse mount
  • 75mm from tube lens to objective

Image Quality:

  • Overall: 6.5 out of 10
  • Center: 7
  • Corner: 6
  • Chromatic Aberration Control: 6

Mounting: The MT-1 is very difficult to install. You can use a Sigma LSA frame to hold the lens in place with the retainer ring. See the website link for more details.

Test Notes:

  • The two main issues with the MT-1 are soft corners and lateral CAs in the center/corners. See the full size image and look at the white edges.
  • Reverse mounting results in better corners, but worse center performance.
  • The performance of the MT-1 normally or reverse mounted was disappointing.
  • The image quality is worse when set-up with the Mitutoyo recommended setup guidelines.

Nikon MXA20696 Tube Lens

https://www.closeuphotography.com/nikon-mxa20696-tube-lens-test/

Set-up:

  • Infinity focus - 240 mm extension sensor to tube lens 
  • Reverse mount
  • 75 mm from tube lens to objective

Image Quality:

  • Overall: 5.5 out of 10
  • Center: 6
  • Corner: 5
  • Chromatic Aberration Control: 5

Mounting: With the Thorlabs 38mm x 0.5 to 52mm x 0.5 adapter this lens is very easy to install. Reverse mount with threaded section or the larger end towards the sensor. See the MXA20696 page for more details.

Test Notes: 

  • Center performance isn't bad but away from the middle the quality drops off quickly. Off-center and corners have an issue with CAs and softness.
  • This lens was shot in at least 6 configurations during testing.
  • Its hard to believe that Nikons sells the MXA20696 as the current recommended tube lens when its is not nearly as good of a performer as Thorlabs ITL200, that is also made by Nikon. So Thorlabs Nikon made ITL200 is much better than Nikon's own tube lens? I have a feeling that the ITL200 is a lens a replacement part used in Nikon's microscopes and is not meant for outside sales.
  • Following Nikons recommended set-up guidelines resulted in a drop in performance, with a rise in CAs and softness in the corners.

Reichert Microscope Tube Lens

Set-up:

  • Infinity focus
  • Normal mount
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 7 out of 10
  • Center: 7
  • Corner: 7 
  • Chromatic Aberration Control: 7

Mounting: This lens was a loaner and came with adapters installed.

Test Notes:

  • Consistent performance across the frame.
  • Unknown mounting threads, test unit came with custom adapter.

Sigma LSA Life Size Attachment Lens

https://www.closeuphotography.com/sigma-life-size-attachment/

Set-up:

  • Short focus, 145 mm extension from sensor to lens
  • Reverse mount
  • 75mm between tube lens and objective

Image Quality:

  • Overall: 7.6 out of 10
  • Center: 8 
  • Corner: 8
  • Chromatic Aberration Control: 7

Mounting: Very easy with 52mm x 0.75 threads. Reverse mount with threaded section towards the objective. See the LSA page for more details.

Test Notes:

  • Short focus produces a sharper image than infinity focus.
  • Infinity focus introduces a lot more chromatic aberrations.
  • Normal mounting this lens introduces more chromatic aberrations.
  • Short focus, or using a lens with less extension than is needed for infinity focus means that it is "focused" beyond infinity. This would create an unusable blurry image, but in many cases this happens to work well with tube lenses - as described here. Short focus results in shorter "effective focal length" used here for magnification calculation purposes, so for example the Sigma LSA with short focus comes in a 183mm effective FL, this would give you 0.91 x the Mitutoyo objectives marked magnification, for the Mitutoyo 5x M Plan lens this would be 4.58x.
  • Compared to a down-sized normal focus image, the pushed down/short focus image is sharper, clean and more detailed.

Nikon Nikkor 200 mm f/4 Ai Telephoto Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 6 out of 10
  • Center: 7
  • Corner: 6 
  • Chromatic Aberration Control: 5

Mounting: Very easy to install an objective on the lens but its just about impossible to get the lens installed in some kind of rigid mount since this lens does not have a tripod collar.

Test Notes:

  • Overall performance about average.
  • Chromatic aberrations are a problem over the entire frame.
  • The Nikon Nikkor 135mm f/3.5 Ai lens is a much better performer.

Carl Zeiss Tele-Tessar T* 200mm f/3.5 Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 5 out of 10
  • Center: 7
  • Corner: 5 
  • Chromatic Aberration Control: 5

Mounting: About impossible to get the lens installed in some kind of rigid mount since this lens does not have a tripod collar.

Test Notes:

  • Largest, heaviest lens in this test.
  • Poor corners on APS-C.
  • This 200 T* lens suffers from chromatic aberrations across the frame.

Asahi  Pentax Tele-Takumar 200mm f/5.6

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 5 out of 10
  • Center: 6
  • Corner: 5 
  • Chromatic Aberration Control: 5

Mounting: Very easy to install an objective on the lens but its just about impossible to get the lens installed in some kind of rigid mount since this lens does not have a tripod collar.

Test Notes:

  • Poor corners on a APS-C sensor.
  • Test image suffers from chromatic aberrations in the center and corners.

Tube Lenses shorter than 200mm

Thorlabs ITL200

https://www.closeuphotography.com/thorlabs-itl200/

Set-up:

  • Short focus, 144 mm extension from sensor to lens
  • Reverse mount
  • 75mm from tube lens to objective

Image Quality:

  • Overall: 9.6 out of 10
  • Center: 8.5
  • Corner: 8.5
  • Chromatic Aberration Control: 10

Mounting: The ITL200 comes with 38 x 0.5 threads but the lens couldn't be easier to install with the optional Thorlabs tube lens adapter equipped with 52 x 0.75 threads. Reverse mount with threaded section or the larger end towards the sensor. See the ITL200 webpage for more details.

Test Notes:

  • Short focus, or using a lens with less extension than is needed for infinity focus means that it is "focused" beyond infinity. This would create an unusable blurry image, but in many cases this happens to work well with tube lenses - as described here. Short focus results in shorter "effective focal length" used here for magnification calculation purposes, so for example the ITL200 with short focus is a 173mm effective FL lens, this would give you 0.865 x Mitutoyo objectives marked magnification, for the Mitutoyo 5x M Plan lens this would be 4.32x.
  • Compared to a down-sized normal focus image, the pushed down/short focus image is sharper, clean and more detailed.
  • Setup with this lens is very easy with the Thorlabs 52mm/SM2 tube lens adapter.
  • Using the official Thorlabs set-up guidelines will result in a performance drop.
  • 3 different samples of this lens were tested.
  • This lens was tested in 7 different configurations, some of these, especially with shorter extension were excellent. Examples of the other set-ups is available here on Closeuphotography.com:

    https://www.closeuphotography.com/thorlabs-itl200/

Century Precision Optics +7 Achromatic Diopter Lens

Closeuphotography.com/raynox-tube-lens

Set-up:

  • Infinity focus
  • Normal mount
  • 50mm extension from tube lens to objective

Image Quality:

  • Overall: 8.5 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 8

Mounting: This lens uses common M58 threads front and rear so it's easy to install with easy to find 58mm step-down adapters.

Test Notes:

  • Lens performs better with 50mm extension from tube lens to objective, minimal extension resulted in slightly more CAs.
  • With lens mounted normally corners were slightly sharper and field was flatter compared to reverse mount.

RAYNOX 208MM (43mm x 0.50 mount)

Raynox-DCR-150-Tube-lens-Closeuphotography-Robert-OToole-Photography.jpg

Also know as: DCR-150, Macroscopic Lens Model M-150, Model CM-2000 1.5X, +4.8 diopter

Closeuphotography.com/raynox-tube-lens

Set-up:

  • Short focus, 144 mm extension from sensor to lens
  • Normal mount
  • 50mm extenstion from tube lens to objective

Image Quality:

  • Overall: 9.6 out of 10
  • Center: 9.5
  • Corner: 10
  • Chromatic Aberration Control: 9.5

Mounting: Thanks to 43mm x 0.5 and 49mm x 0.5 threads this lens is easy to install once you purchase the necessary step-down adapters.

Test Notes:

  • Short focus, or using a lens with less extension than is needed for infinity focus means that it is "focused" beyond infinity. This would create an unusable blurry image, but in many cases this happens to work well with tube lenses - as described here. Short focus results in shorter "effective focal length" used here for magnification calculation purposes, so for example the Raynox +4.8, 208mm lens, with short focus is a 178mm effective FL lens, this would give you .859 x the Mitutoyo objectives marked magnification, for the Mitutoyo 5x M Plan lens this would be 4.29x.
  • Compared to a down-sized normal focus image, the pushed down/short focus image is sharper, clean and more detailed.
  • Adding more extension for infinity focus results in lower sharpness and less detail across the frame.
  • 3 different samples of the this lens were tested.
  • This lens was tested in 9 different configurations, some of these, especially those with shorter extension, were excellent. Examples of the other set-ups is available here on Closeuphotography.com: Closeuphotography.com/raynox-tube-lens

Raynox 170mm (37mm x 0.5 mount)

Also know as: RAYNOX DIGITAL CAMERA MACROSCOPIC LENS 2X, 35mm Microscopic Lens 6x model CM-3500, Raynox video microscope lens 35x, +5.9 diopter

Closeuphotography.com/raynox-tube-lens

Set-up:

  • Infinity focus 
  • Normal mount
  • Minimal space between lens and objective

Image Quality:

  • Overall: 8.8 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 8.5

Mounting: This Raynox does not have any front threads so its just about impossible to mount this lens as a tube lens. I use a donor Sigma LSA, removed the glass, and use glassless mount hold this lens. There is a step in the LSA adapter that fits the back side of the Raynox so the lens is always centered.

Test Notes:

  • Normal mount has sharper corners than reverse.
  • Quite a bit of field curvature normally mounted.
  • 6 different configurations with this lens were tested.

Sigma 150mm F2.8 EX DG OS HSM APO Macro Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 9.5 out of 10
  • Center: 9
  • Corner: 9 
  • Chromatic Aberration Control: 9

Mounting: This lens will require a 72mm x 0.75 step down adapter to install an objective but the lens is easy to mount on a stand since it's equipped with a tripod collar.

Test Notes:

  • The Sigma 150 images are so sharp that the crops look over-sharpened but in fact they were processed identically to every lens in this test using actions and batch conversions.
  • Extremely sharp and detailed crops from center to corner.
  • APO correction.
  • Very flat field.

Nikon Nikkor 135mm f/3.5 Ai Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 9 out of 10
  • Center: 9
  • Corner: 9 
  • Chromatic Aberration Control: 8.5

Mounting: Very easy to install an objective on the lens but its just about impossible to get the lens installed in some kind of rigid mount since this lens does not have a tripod collar.

Test Notes:

  • The CA correction on the 135/3.5 Nikkor is very similar to an APO corrected lens.
  • Flat field without any field curvature.
  • This lens is a bargain with a cost around $50 USD on Ebay.

Voigtlander APO-Lanthar 125mm f/2.5 Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 9.5 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 9.5

Mounting: Very easy to install an objective on the lens but its just about impossible to get the lens installed in some kind of rigid mount since this lens does not have a tripod collar.

Test Notes:

  • APO correction.
  • Very flat field.

RAYNOX 125mm (43mm mount)

Also know as: MACROSCOPIC LENS MODEL M-250,  Model DCR-250, Model CM-2000 2.5X,  +8 diopter

Closeuphotography.com/raynox-tube-lens

Set-up:

  • Infinity focus 
  • Normal mount
  • Minimal space between lens and objective

Image Quality:

  • Overall: 9.5 out of 10
  • Center: 9
  • Corner: 9
  • Chromatic Aberration Control: 9

Mounting: Thanks to 43mm x 0.5 and 49mm x 0.5 threads this lens is easy to install once you purchase the necessary step-down adapters.

Test Notes:

  • Performance of this lens is very close the Voigtlander APO-Lanthar.
  • Reverse mounting results in more CAs.
  • More spacing between lens and objective results in more CAs.
  • Very flat field.
  • 4 different configurations with this lens were tested.

Tube LensesLonger than 200mm

Century Precision Optics +4 Achromatic Diopter Lens

Set-up:

  • Infinity focus
  • Normal mount
  • 110mm of extension between tube lens and objective was best

Image Quality:

  • Overall: 8.5 out of 10
  • Center: 8
  • Corner: 8
  • Chromatic Aberration Control: 8

Mounting: This lens uses common 58mm x 0.5 threads front and rear so it's easy to install with easy to find 58mm x 0.5 step-down adapters.

Test Notes:

  • Best tube lens over 200mm.
  • Completely flat field.
  • This lens also performs very well pushed down to an effective 206mm focal length with a short focus setup.

 Cosina MMA Matched Macro Adapter Lens

Set-up:

  • Infinity focus
  • 50mm extension between tube lens and objective

Image Quality:

  • Overall: 5.3 out of 10
  • Center: 6
  • Corner: 5
  • Chromatic Aberration Control: 5

Mounting: This lens has 49mm x 0.5 threads so the installation is easy with two adapters.

Test Notes:

  • Lateral CAs in the corners.
  • Construction looks identical to the Sigma LSA lens.

Canon 250D +4 Close-up Lens

Set-up:

  • Infinity focus
  • Minimal space between tube lens and objective

Image Quality:

  • Overall: 4 out of 10
  • Center: 4
  • Corner: 4
  • Chromatic Aberration Control: 4

Mounting: This lens is not recommended for use as a tube lens.

Test Notes:

  • Consistently poor performance over the entire frame.
  • Does not cover APS-C.
  • Worst performance of any lens in this test.

Test Notes

  • The best lens overall is the ITL200, the performance of this lens was near perfect and it's one of the easiest to mount thanks to an 52mm adapter from Thorlabs.
  • The Century +4, Sigma LSA, and Thorlabs ITL200 lenses all performed very well with short focus, that is, pushed down with less extension that is needed for infinity focus. Short focus, or using a lens with less extension than is needed for infinity focus means that it is "focused" beyond infinity. This would create an unusable blurry image, but in many cases this happens to work well with tube lenses - as described here. Short focus results in shorter "effective focal length" used here for magnification calculation purposes. Compared to a down-sized normal focus image, the pushed down/short focus image is sharper, clean and more detailed.
  • Higher cost does not always equal better performance, some of the best lenses in the test cost about $50 or less.
  • Its hard to believe that Nikons sells the MXA20696 as the current recommended tube lens when its is not nearly as good of a performer as Thorlabs ITL200, also made by Nikon.
  • The performance of the Nikon MXA20696, and Mitutoyo MT-1 was underwhelming.
  • Special thanks to Chris and Saul for the long term loaner tube lenses.

THE BEST AT 200mm 

Excellent
Thorlabs ITL200 Tube Lens [infinity] - 9.3 - Overall best at 200mm
Century Precision Optics +4 Achromatic Diopter Lens [pushed down with short extension] - 9
Raynox +4.8 diopter - 8

You can go wrong with any of these three, they are all sharp, contrasty, flat and easy to mount.

Good
Sigma LSA Life Size Attachment Lens - 7.6
Reichert Microscope Tube Lens - 7

The Sigma and Reichert are both good lensed and make a nice image with the Mitutoyo, but the CAs are a little higher than the other 200mm lenses. The pushed down Century was a big surprise.

THE WORST AT 200mm

Average
Mitutoyo MT-1 Tube lens - 6.5
Nikkor 200mm f/4 Ai - 6
Nikon MXA20696 Tube Lens - 5.5
Asahi  Pentax Tele-Takumar 200mm f/5.6 - 5
Carl Zeiss Tele-Tessar T* 200mm f/3.5 - 5

THE best Tube lenses shorter than 200mm

Excellent
Thorlabs ITL200 Tube Lens [pushed down with short extension] - 9.6 - Overall best at shorter than 200
Raynox +4.8 diopter [pushed down with short extension] - 9.6
Sigma 150mm F2.8 EX DG OS HSM APO Macro - 9.5
Voigtlander APO-Lanthar 125mm f/2.5 - 9.5
Raynox +8 diopter - 9.5
Nikkor 135mm f/3.5 Ai - 9
Century Precision Optics +7 Achromatic Diopter Lens  - 8.5
Raynox +5.9 diopter - 9.5

All of these lenses are just excellent, clean sharp and super CA control. The big surprise here was the performance with the pushed down ITL200 and Raynox. 

the best Tube lenses longer than 200mm 

Excellent
Century Precision Optics +4 Achromatic Diopter Lens - 8.5 - Overall best at 200mm+
Average
Cosina MMA Matched Macro Adapter Lens - 5.3

The Worst lens longer than 200mm

Poor
Canon 250D Close-up Lens - 4