Ø2" Lens Tubes
- Directly Accepts Ø2" (50.8 mm) Optics
- Compatible with SM2-Threaded Components
- Designed for use with Our 60 mm Cage Systems
Easily Interface with Other Lens Tube Sizes
|Lens Tube Couplers
SM Thread Adapters
Lens Tube Mounts
Fixed Lens Mounts
- Variety of Lens Tubes in Lengths from 0.30" (7.6 mm) to 3.00" (76.2 mm)
- Standard Lens Tubes
- Lens Tubes without External Threading
- Slotted Lens Tubes for Access to Optics without Disassembly
- Extension Tube for Optics with Long Focal Lengths
- Wide Range of SM2 (2.035"-40) Compatible Optomechanical Components
- Compatible with Our 60 mm Cage Systems
- Lens Tubes Directly Accept Ø2" (50.8 mm) Optics
Lens tubes are ideal for creating compact optical subassemblies with light-tight beam paths. The Ø2" lens tubes sold here can be used to house one or several optical elements, as shown in the diagram of a beam expander below. In addition to the Ø2" lens tubes featured on this page, Thorlabs also offers Ø1/2", Ø1", Ø30 mm, Ø1.5", and Ø3" versions, each of which is equipped with an SM series thread standard that depends on the tube diameter. Vacuum-compatible versions of our Ø1/2" and Ø1" stackable lens tubes are available from stock; customers can request vacuum-compatible lens tubes at other lengths and diameters by contacting Tech Support.
Optics are separated and secured by retaining rings that are positioned at the desired depth within the lens tube using our SPW604 spanner wrench. Depending on the item purchased, one or two retaining rings will be included (see below for details). Additional retaining rings can be purchased separately.
Click to Enlarge
When an engraved lens tube is attached to another lens tube, the engraving of the connected end is no longer visible.
|Lens Tube Compatible Products|
|Fixed Fiber Collimator
|Kinematic Fiber Collimator
|LED Mounts||LD Mounts||Aspheric Lens Mounts||Irises, Apertures, and Shutters||Alignment Tools|
|SM05 Threading: Ø1/2" Lens Tubes, 16 mm Cage Systems|
|External Thread, 0.535"-40.0 UNS-2A||Internal Thread, 0.535"-40.0 UNS-2B|
|Max Major Diameter||0.5340"||Min Major Diameter||0.5350"|
|Min Major Diameter||0.5289"||Min Pitch Diameter||0.5188"|
|Max Pitch Diameter||0.5178"||Max Pitch Diameter||0.5230"|
|Min Pitch Diameter||0.5146"||Min Minor Diameter (and 83.3% of Thread)||0.508"|
|Max Minor Diameter||0.5069"||Max Minor Diameter (and 64.9% of Thread)||0.514"|
|RMS Threading: Objective, Scan, and Tube Lenses|
|External Thread, 0.800"-36.0 UNS-2A||Internal Thread, 0.800"-36.0 UNS-2B|
|Max Major Diameter||0.7989"||Min Major Diameter||0.8000"|
|Min Major Diameter||0.7934"||Min Pitch Diameter||0.7820"|
|Max Pitch Diameter||0.7809"||Max Pitch Diameter||0.7866"|
|Min Pitch Diameter||0.7774"||Min Minor Diameter (and 83.3% of Thread)||0.770"|
|Max Minor Diameter||0.7688"||Max Minor Diameter (and 64.9% of Thread)||0.777"|
|C-Mount Threading: Machine Vision Lenses, CCD/CMOS Cameras|
|External Thread, 1.000"-32.0 UN-2A||Internal Thread, 1.000"-32.0 UN-2B|
|Max Major Diameter||0.9989"||Min Major Diameter||1.0000"|
|Min Major Diameter||0.9929"||Min Pitch Diameter||0.9797"|
|Max Pitch Diameter||0.9786"||Max Pitch Diameter||0.9846"|
|Min Pitch Diameter||0.9748"||Min Minor Diameter (and 83.3% of Thread)||0.966"|
|Max Minor Diameter||0.9651"||Max Minor Diameter (and 64.9% of Thread)||0.974"|
|SM1 Threading: Ø1" Lens Tubes, 30 mm Cage Systems|
|External Thread, 1.035"-40.0 UNS-2A||Internal Thread, 1.035"-40.0 UNS-2B|
|Max Major Diameter||1.0339"||Min Major Diameter||1.0350"|
|Min Major Diameter||1.0288"||Min Pitch Diameter||1.0188"|
|Max Pitch Diameter||1.0177"||Max Pitch Diameter||1.0234"|
|Min Pitch Diameter||1.0142"||Min Minor Diameter (and 83.3% of Thread)||1.008"|
|Max Minor Diameter||1.0068"||Max Minor Diameter (and 64.9% of Thread)||1.014"|
|SM30 Threading: Ø30 mm Lens Tubes|
|External Thread, M30.5 x 0.5 – 6H/6g||Internal Thread, M30.5 x 0.5 – 6H/6g|
|Max Major Diameter||30.480 mm||Min Major Diameter||30.500 mm|
|Min Major Diameter||30.371 mm||Min Pitch Diameter||30.175 mm|
|Max Pitch Diameter||30.155 mm||Max Pitch Diameter||30.302 mm|
|Min Pitch Diameter||30.059 mm||Min Minor Diameter (and 83.3% of Thread)||29.959 mm|
|Max Minor Diameter||29.938 mm||Max Minor Diameter (and 64.9% of Thread)||30.094 mm|
|SM1.5 Threading: Ø1.5" Lens Tubes|
|External Thread, 1.535"-40 UNS-2A||Internal Thread, 1.535"-40 UNS-2B|
|Max Major Diameter||1.5339"||Min Major Diameter||1.535"|
|Min Major Diameter||1.5288"||Min Pitch Diameter||1.5188"|
|Max Pitch Diameter||1.5177"||Max Pitch Diameter||1.5236"|
|Min Pitch Diameter||1.5140"||Min Minor Diameter (and 83.3% of Thread)||1.508"|
|Max Minor Diameter||1.5068"||Max Minor Diameter (and 64.9% of Thread)||1.514"|
|SM2 Threading: Ø2" Lens Tubes, 60 mm Cage Systems|
|External Thread, 2.035"-40.0 UNS-2A||Internal Thread, 2.035"-40.0 UNS-2B|
|Max Major Diameter||2.0338"||Min Major Diameter||2.0350"|
|Min Major Diameter||2.0287"||Min Pitch Diameter||2.0188"|
|Max Pitch Diameter||2.0176"||Max Pitch Diameter||2.0239"|
|Min Pitch Diameter||2.0137"||Min Minor Diameter (and 83.3% of Thread)||2.008"|
|Max Minor Diameter||2.0067"||Max Minor Diameter (and 64.9% of Thread)||2.014"|
|SM3 Threading: Ø3" Lens Tubes|
|External Thread, 3.035"-40.0 UNS-2A||Internal Thread, 3.035"-40.0 UNS-2B|
|Max Major Diameter||3.0337"||Min Major Diameter||3.0350"|
|Min Major Diameter||3.0286"||Min Pitch Diameter||3.0188"|
|Max Pitch Diameter||3.0175"||Max Pitch Diameter||3.0242"|
|Min Pitch Diameter||3.0133"||Min Minor Diameter (and 83.3% of Thread)||3.008"|
|Max Minor Diameter||3.0066"||Max Minor Diameter (and 64.9% of Thread)||3.014"|
|SM4 Threading: Ø4" Lens Tubes|
|External Thread, 4.035"-40 UNS-2A||Internal Thread, 4.035"-40.0 UNS-2B|
|Max Major Diameter||4.0337"||Min Major Diameter||4.0350"|
|Min Major Diameter||4.0286"||Min Pitch Diameter||4.0188"|
|Max Pitch Diameter||4.0175"||Max Pitch Diameter||4.0245"|
|Min Pitch Diameter||4.0131"||Min Minor Diameter (and 83.3% of Thread)||4.008"|
|Max Minor Diameter||4.0066"||Max Minor Diameter (and 64.9% of Thread)||4.014"|
Shan Xu  (posted 2021-08-13 23:04:29.707)
Could you offer a 2 mm version of your 2.5mm SM2RR retaining rings?
cdolbashian  (posted 2021-08-19 03:05:35.0)
Thank you for reaching out to us at Thorlabs with this request. I have contacted you directly regarding regarding the feasibility of this custom version of the SM2RR.
Ludovic A.  (posted 2021-01-22 09:51:33.083)
Could you offer a 4" and/or 5" version of your 6" SM2 thick wall Extension tube? While it's acceptable to stack shorter tubes to reach the desired length, your current offering of SM2 tubes stops at 3.5" and jumps to 6". Intermediate versions of SM2 extension tubes would be much welcome (thick walled would be best, they could also be stackable (as your SM2Lxx) or without ext. thread (SM2Exx)). My current application makes use of a large format and heavy line scan lens with a long flange focal distance and I regularly use long lengths of SM2 tubes in other applications.
YLohia  (posted 2021-01-22 01:56:03.0)
Thank you for your feedback. We will consider adding other lengths of these lens tubes to our catalog in the future. For immediate customizations, quotes can be requested by clicking the "Request Quote" button above. We will discuss this customization directly.
Van Van Rudd  (posted 2020-08-03 11:55:09.33)
Are the lens tubes vacuum compatible? Could you make ones that are?
YLohia  (posted 2020-08-03 02:04:10.0)
Thank you for contacting Thorlabs. These lens tubes are anodized and, thus, not vacuum-compatible. Custom unanodized versions can be requested by emailing email@example.com.
Max D  (posted 2019-06-04 05:17:05.527)
Hi Thorlabs team, I would like to know what is the tolerance on tilt of a flat surface within your SM2M10 tube by using SM2 retainer ring. Regards.
llamb  (posted 2019-06-05 08:32:19.0)
Hello, thank you for contacting Thorlabs. The exact tip/tilt of an optic will greatly depend on the optic's flatness/parallelism as well as the lens tube. I have reached out to you directly to discuss this lens tube's tolerances and your application's needs further.
ger.folkersma  (posted 2016-06-30 04:53:01.43)
Hi, the Solidowrks model of the SM2L15 seems to be corrupted. All other tube models work fine.
s.kovalev  (posted 2015-10-13 20:29:52.873)
Hello. Do you have 2'' tubes with 6'' length or can you make it for us. Thanks Sergey.
besembeson  (posted 2015-10-13 03:57:52.0)
Response from Bweh at Thorlabs USA: Yes we do. It seems the SM2E60 may be suitable for you - http://www.thorlabs.com/thorproduct.cfm?partnumber=SM2E60
cqtttv  (posted 2013-07-22 17:48:37.463)
What is the tolerance on the diameter and sphericity?
jlow  (posted 2013-07-22 15:58:00.0)
Response from Jeremy at Thorlabs: I will contact you directly to discuss about your application and provide this information.
- SM2-Threaded (2.035"-40) Bore Accepts Ø2" (Ø50.8 mm) Optics
- Stackable Design Enables Multi-Element Optical Systems
- Compatible with Our 60 mm Cage Assembly Systems
These stackable Ø2" Lens Tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with all SM2-threaded (2.035"-40) components provide flexibility for complex optomechanical assemblies. One SM2RR Retaining Ring is included with each lens tube.
Click to Enlarge
An SM2L15 lens tube used to mount a SOLIS-1A high-powered LED.
|Item #||L||Internal Thread Depth|
|SM2L03||0.33" (8.4 mm)||0.30" (7.6 mm)|
|SM2L05||0.53" (13.5 mm)||0.50" (12.7 mm)|
|SM2L10||1.03" (26.2 mm)||1.00" (25.4 mm)|
|SM2L15||1.53" (38.9 mm)||1.50" (38.1 mm)|
|SM2L20||2.03" (51.6 mm)||2.00" (50.8 mm)|
|SM2L30||3.03" (77.0 mm)||3.00" (76.2 mm)|
- SM2-Threaded (2.035"-40) Bore Accepts Ø2" (Ø50.8 mm) Optics
- Unlike Stackable Lens Tubes, Optics can be Accessed from Both Ends
- Use Lens Tube Couplers to Stack Multiple Lens Tubes
- Allows Coupling of Two Components with External SM2 Threading
- Directly Compatible with Our 60 mm Cage Assembly Systems
Unlike our Ø2" stackable lens tubes featured above, these Internally Threaded Lens Tubes do not feature a lip at one end nor do they have external SM2 threading. Therefore, optics housed inside can be accessed from both ends. To join these lens tubes end-to-end, use an SM2T2 Lens Tube Coupler. Two SM2RR Retaining Rings are included with each lens tube.
- Easy Access to Optics
- Rotatable Slip Shield Protects Optics
- Compatible with SM2-Threaded Components
These stackable Ø2" Lens Tubes with side slots provide a fast and easy means for building complex optical assemblies and adjusting the optics without disassembling the setup. Several optics can be inserted into a single tube using multiple SM2RR Retaining Rings. Simply thread the first retaining ring to the desired depth, add the optic, and then use a second retaining ring to secure the optic. Optics can be manually adjusted via the side slots without the use of a spanner wrench. The rotatable slip shield included with the lens tube fits over the lens tube slots to prevent unwanted light from entering the system and to keep the optical setup free from debris. Two retaining rings and one black plastic dust cover are included with each lens tube.
The SM2E60 6" Long Extension Tube is designed to enable longer distances between optical components in lens tube systems that utilize lenses with large focal lengths. Although the ends of these extension tubes are threaded to accept our SM2 series stackable lens tubes, they feature thicker walls than our standard lens tubes, which leads to greater rigidity.
|Alternatives||Ø1" Lens Tube Extensions|
|Retaining Ring Specs|
|SM2RR||Black Anodized Aluminum||Standard||0.10"
|SM2RRV||Unanodized Aluminum||Vacuum Compatiblea||0.10"
|SM2LTRR||Black Anodized Aluminum||Rubber O-Ring
for Stress-Free Mounting
|SM2RRC||Black Anodized Aluminum||5 mm Thick for
|POLARIS-SM2RR||Stainless Steel||Vacuum Compatibleb||0.10"
- Five Types of Retaining Rings for Securing Ø2" Optics
- SPW604 Hollow Spanner Wrench Providing Unobstructed Beam Path During Adjustment
- SPW801 Adjustable Spanner Wrench Accommodates Diameters from 0.12" (3.0 mm) to 2.89" (73.4 mm)
The SM2RR is our standard anodized aluminum retaining ring that ships with our Ø2" lens tubes as well as many other Thorlabs components and is available individually and in packs of 5. We offer five different SM2-threaded (2.035"-40) retaining rings, shown in the table to the right, which have unique features and can replace an SM2RR retaining ring. Please keep in mind that due to the increased thickness of some retaining rings, the maximum optic thickness that can be housed inside our standard SM2-compatible mounts will be diminished in some cases.
We offer two spanner wrench choices that can be used with these retaining rings. The SPW604 Spanner Wrench has a hollow design that enables retaining rings for our SM2 lens tubes to be adjusted and installed without obscuring the beam path. The handle is knurled for improved grip. Alternatively, the SPW801 Adjustable Spanner Wrench can also be used to position SM2-threaded retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 inch-pounds. We also offer the SPB2 Spanner Bit, which can be used with a standard 1/4" hex driver (sold separately). The SPB2 is included as part of the SPB600 Spanner Wrench Bit Kit.