Adjustable C-Mount Extension Tubes

Rotating Adjustable Extension Tube for C-Mount Components
Internal and External C-Mount (1.00"-32) Threads
Slotted Locking Ring Available for Additional Tightening

CMV10

1" External Thread

CMV05

0.5" External Thread

CMNT1

Slotted Locking Ring

SPW502

Spanner Wrench for
Slotted Locking Rings

Related Items

C-Mount Extension Tubes

CCD and CMOS Cameras

C-Mount Tube Accessories

C-Mount Camera Lenses

High Magnification Zoom Lenses

C-Mount Tube Mounts

Lens Tubes

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Overview
Threading Specs
Object Distances
Feedback

Adjustable C-Mount Extension Tube Usage

Item #	External Thread Length	Maximum Adjustment Range^a
CMV05	0.5" (12.7 mm)	0.31" (7.9 mm)
CMV10	1.0" (25.4 mm)	0.81" (20.6 mm)

Including one CMNT locking ring and 0.08" (2 mm) minimum thread depth for the attached extension tube or component.

Features

Two Adjustment Ranges
- CMV05: 0.31" (7.9 mm)
- CMV10: 0.81" (20.6 mm)
Long Externally Threaded Section for Adjustable Positioning of Mounted Lens

These C-Mount adjustable extension tubes have an extra-long externally threaded section, allowing the distance between a camera lens and CCD/CMOS camera to be adjusted. To operate, mount the camera lens, then thread the adjustable extension tube into the camera until the lens is at the desired distance from the camera, as illustrated in the animation to the right. Use the included CMNT locking ring to fix the position of the extension tube. Like our standard extension tubes, these adjustable extension tubes are made of black-anodized aluminum.

For applications where it is difficult to reach the locking ring by hand, we offer the CMNT1 Slotted Locking Ring and SPW502 Spanner Wrench. This locking ring contains slots for the 1¼" end of the spanner wrench.

Thorlabs' Threading Specifications

Thorlabs' lens tubes utilize a series of non-standard threadings. Threading specifications are given below for our SM threadings utilized in our lens tube and cage system components so that you can machine mating components to suit your application. We also offer products with C-Mount and RMS threadings, and the specifications for these threadings are also given below. Please note that other manufacturers may have different tolerances for these threads. For other thread specifications that are not listed here, please contact Tech Support.

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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, M30.5x0.5		Internal Thread, M30.5x0.5
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"

Thorlabs' Camera Lenses for Machine Vision each have a characteristic range of object distances. Objects placed within this range can be brought to a sharp focus on the sensor of the C-Mount camera. As seen in the image sequence below, the addition of an extension tube between the camera and the lens changes this range of object distances and allows the system to focus on objects closer to the lens. This increases the magnification of the image on the camera while decreasing the depth of field. The following table lists the range of possible object distances for various combinations of Thorlabs' C-Mount extension tubes and machine vision lenses.

Note that Thorlabs' camera lenses are designed to correct for optical aberrations witin a specified range of object distances. The modification of the specified minimum object distance with an extension tube may reduce the ability of these lenses to eliminate aberrations.

14" (356 mm) Object Distance
No Spacer

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4" (102 mm) Object Distance
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4" (102 mm) Object Distance
5 mm Spacer

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5/8" (16 mm) Object Distance
20 mm (15 mm + 5 mm) Spacer

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Click Here for Raw (2048 x 2048) Image

RSP1X15 rotation mount imaged using a previous-generation scientific camera (Item # 4070M-GE) and MVL25M43 Lens at different object distances. A 20 mm spacer was created by using CML05 and CML15 spacers together.

Object Distance and Magnification for Lens and Spacer Combinations
Camera Lens	Focal Length	Design Format	No Spacer		1 mm Spacer		5 mm Spacer		10 mm Spacer		20 mm Spacer
Camera Lens	Focal Length	Design Format	Minimum Object Distance	Magnification	Minimum Object Distance	Magnification	Minimum Object Distance	Magnification	Minimum Object Distance	Magnification	Minimum Object Distance	Magnification
MVL8M23	8 mm	2/3"	120 mm	0.07	30 mm	0.2	-	-	-	-	-	-
MVL12M23	12 mm	2/3"	150 mm	0.08	70 mm	0.16	-	-	-	-	-	-
MVL12M1	12 mm	1"	300 mm	0.04	93 mm	0.12	-	-	-	-	-	-
MVL12M43	12 mm	4/3"	100 mm	0.1	48 mm	0.19	-	-	-	-	-	-
MVL16M23	16 mm	2/3"	200 mm	0.08	110 mm	0.14	-	-	-	-	-	-
MVL16M1	16 mm	1"	300 mm	0.05	134 mm	0.11	-	-	-	-	-	-
MVL25M23	25 mm	2/3"	200 mm	0.12	150 mm	0.16	73 mm	0.31	-	-	-	-
MVL25TM23	25 mm	2/3"	100 mm	0.24	79 mm	0.28	46 mm	0.44	29 mm	0.63	-	-
MVL25M1	25 mm	1"	300 mm	0.08	200 mm	0.12	83 mm	0.28	-	-	-	-
MVL25M43	25 mm	4/3"	150 mm	0.15	115 mm	0.19	56 mm	0.35	31 mm	0.55	12 mm	0.96
MVL35M23	35 mm	2/3"	200 mm	0.18	175 mm	0.21	115 mm	0.32	81 mm	0.46	51 mm	0.73
MVL35M1	35 mm	1"	300 mm	0.12	243 mm	0.15	138 mm	0.26	91 mm	0.4	-	-
MVL50M23	50 mm	2/3"	200 mm	0.3	190 mm	0.32	160 mm	0.39	135 mm	0.48	105 mm	0.65
MVL50TM23	50 mm	2/3"	100 mm	0.46	91 mm	0.48	76 mm	0.58	64 mm	0.7	49 mm	0.94
MVL50M1	50 mm	1"	500 mm	0.11	424 mm	0.13	269 mm	0.2	189 mm	0.3	124 mm	0.5
MVL75M1	75 mm	1"	1000 mm	0.078	858 mm	0.091	553 mm	0.14	389 mm	0.21	251 mm	0.34
MVL75M23	75 mm	2/3"	1200 mm	0.07	1010 mm	0.08	630 mm	0.13	440 mm	0.2	285 mm	0.34
MVL100M23	100 mm	2/3"	2000 mm	0.05	1700 mm	0.06	1060 mm	0.1	740 mm	0.15	480 mm	0.25

Posted Comments:
Richard Drye (posted 2020-09-08 08:11:52.79) Would love to see the CMV10/CMV05, but with SM1 internal threads so I dont have to also include a SM1A9. This buys a few extra critical millimeters when working with shorter focal lengths. YLohia (posted 2020-09-09 11:16:19.0) Hello Richard, thank you for your feedback. We will consider adding such an item to our catalog in the future.