Imaging/Focusing Microscope Objectives, Dry

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Super Apochromatic Objectives
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Objective Lens Selection Guide
Objectives
Super Apochromatic Microscope Objectives Microscopy Objectives, Dry Microscopy Objectives, Oil Immersion Physiology Objectives, Water Dipping or Immersion Long Working Distance Objectives Reflective Microscopy Objectives UV Microscopy Objectives 532 nm and 1064 nm Objectives
Scan Lenses and Tube Lenses
Scan Lenses Infinity-Corrected Tube Lens

Did You Know?

Multiple optical elements, including the microscope objective, tube lens, and eyepieces, together define the magnification of a system. See the Magnification & FOV tab to learn more.

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Example of a Dry Objective Design
(See Objective Tutorial Tab for More Information About Microscope Objective Types)

Thorlabs offers dry objectives made in house, as well as objectives from Olympus, Nikon, and Mitutoyo. Plan achromat, plan fluorite (also called plan semi-apochromat or plan fluor), and plan apochromat designs are available. For details about the differences between these types of objectives, please see the Objective Tutorial tab above.

The Thorlabs objective and the Nikon objectives have M25 x 0.75 threading and are designed for a tube lens with focal length 200 mm. The Olympus objectives on this page have RMS (0.800"-36) threading and are designed for a tube lens with focal length 180 mm. The Mitutoyo objectives have M26 x 0.706 threading and are designed for a tube lens with focal length 200 mm. When choosing a microscope objective, it is important to keep in mind that objectives are often designed to integrate with a particular manufacturer's microscopes and are not necessarily interchangeable due to tube length differences and variations in thread pitch or diameter. Please note that the performance of each objective may vary from the engraved specifications when integrated with components and systems from different manufacturers. See the Magnification and FOV tab for more information.

These microscope objectives should be used in applications like traditional microscopy, confocal imaging, and fiber coupling, and are suitable for use in a variety of imaging modalities, including epi-illumination, oblique illumination, brightfield, and DIC applications.These infinity-corrected objectives have optical elements with an ultra-wide broadband AR coating. They are compatible with many of the microscopy and fiber coupling accessories offered by Thorlabs.

All objectives featured on this page are compatible with our microscope nosepiece modules for DIY Cerna^® systems, which accept RMS, M25 x 0.75, or M32 x 0.75 objective threading. The Olympus microscope objectives can be mounted directly to our fiber launch systems, or mounted into our 30 mm cage system using the CP16 RMS-threaded cage plate, which is also post mountable. They can also be mounted to any of our multi-axis platforms or translation stages using an HCS013 RMS mount. Please note that the multi-axis platforms and translation stages need a 3 mm wide central keyway for the HCS013 RMS mount.

Alternatively, all of the microscope objectives featured below can be easily mounted to our cage systems or lens tubes using Thorlabs' thread adapters, thus facilitating the setup of optical systems. To convert an objective to the SM1 (1.035"-40) thread standard used in many Thorlabs components, we recommend the SM1A3 adapter for the Olympus objectives, the SM1A12 adapter for the Thorlabs and Nikon objectives, and the SM1A27 adapter for the Mitutoyo objectives.

Thorlabs Super Apochromatic Objectives
Magnification	2X	4X	5X	10X	20X	40X	60X	100X
Item #	TL2X-SAP	TL4X-SAP	-	-	-	-	-	-
Numerical Aperture (NA)	0.10	0.20	-	-	-	-	-	-
Field of View	Ø11 mm	Ø5.5 mm	-	-	-	-	-	-
Field Number	22^a		-	-	-	-	-	-
Working Distance (WD)^b	56.3 mm	17 mm	-	-	-	-	-	-
Effective Focal Length	100 mm	50 mm
Parfocal Length^b	95.0 mm	60 mm	-	-	-	-	-	-
Design Tube Lens Focal Length^c	200 mm		-	-	-	-	-	-
Coverslip Correction	-	-	-	-	-	-	-	-
Diameter^b	30.5 mm		-	-	-	-	-	-
Length^b	43.5 mm	46.4 mm	-	-	-	-	-	-
Threading	M25 x 0.75^d		-	-	-	-	-	-
Wavelength Range	350 - 700 nm		-	-	-	-	-	-

Olympus Plan Achromat Objectives
Magnification	2X	4X	5X	10X	20X	40X	60X	100X
Item #	-	RMS4X	-	RMS10X	RMS20X	RMS40X	-	-
Manufacturer Part #	-	1-U2B222	-	1-U2B223	1-U2B225	1-U2B227	-	-
Numerical Aperture (NA)	-	0.10	-	0.25	0.40	0.65	-	-
Field Number	-	22	-	22	22	22	-	-
Working Distance (WD)^b	-	18.5 mm	-	10.6 mm	1.2 mm	0.6 mm	-	-
Effective Focal Length (EFL)	-	45 mm	-	18 mm	9.0 mm	4.5 mm	-	-
Parfocal Length^b	-	45.06 mm	-	45.06 mm			-	-
Design Tube Lens Focal Length^c	-	180 mm	-	180 mm			-	-
Coverslip Correction^e	-	-	-	-	0.17 mm	0.17 mm	-	-
Diameter^b	-	24.0 mm	-	24.0 mm			-	-
Length^b	-	30.9 mm	-	38.8 mm	48.5 mm	48.8 mm	-	-
Threading	-	RMS^f	-	RMS^f			-	-
Wavelength Range	-	Visible	-	Visible			-	-

Olympus Plan Fluorite Objectives
Magnification	2X	4X	5X	10X	20X	40X	60X	100X
Item #	-	RMS4X-PF	-	RMS10X-PF	RMS20X-PF	RMS40X-PF	RMS60X-PFC	-
Manufacturer Part #	-	1-U2B522	-	1-U2B524	1-U2B525	1-U2B527	1-U2B531	-
Numerical Aperture (NA)	-	0.13	-	0.30	0.50	0.75	0.90	-
Field Number	-	26.5	-	26.5	26.5	26.5	26.5	-
Working Distance (WD)^b	-	17 mm	-	10 mm	2.1 mm	0.51 mm	0.2 mm	-
Parfocal Length^b	-	45.06 mm	-	45.06 mm				-
Design Tube Lens Focal Length^c	-	180 mm	-	180 mm				-
Coverslip Correction^e	-	-	-	0.17 mm	0.17 mm	0.17 mm	0.11 - 0.23 mm	-
Diameter^b	-	24.0 mm	-	24.0 mm	26.0 mm	26.0 mm	31.0 mm (w/ Collar)	-
Length^b	-	32.4 mm	-	39.4 mm	47.3 mm	48.9 mm	49.4 mm	-
Threading	-	RMS^f	-	RMS^f				-
Wavelength Range	-	Visible and NIR	-	Visible and NIR				-

Nikon Plan Fluorite Objectives
Magnification	2X	4X	5X	10X	20X	40X	60X	100X
Item #	-	N4X-PF	-	N10X-PF	N20X-PF	N40X-PF	N60X-PF	-
Manufacturer Part #	-	MRH00041	-	MRH00101	MRH00201	MRH00401	MRH00602	-
Numerical Aperture (NA)	-	0.13	-	0.30	0.50	0.75	0.85	-
Working Distance (WD)^b	-	17.2 mm	-	16 mm	2.1 mm	0.66 mm	0.31 - 0.4 mm	-
Parfocal Length^b	-	60 mm	-	60 mm				-
Design Tube Lens Focal Length^c	-	200 mm	-	200 mm				-
Coverslip Correction^e	-	-	-	0.17 mm	0.17 mm	0.17 mm	0.11 - 0.23 mm	-
Diameter^b	-	30.0 mm	-	30.0 mm	28.0 mm	30.0 mm	31.4 mm (w/ Collar)	-
Length^b	-	46.6 mm	-	48.7 mm	63.5 mm	64.3 mm	64.3 mm	-
Threading	-	M25 x 0.75^d	-	M25 x 0.75^d				-

Mitutoyo Plan Apochromat Objectives
Magnification	2X	4X	5X	10X	20X	40X	60X	100X
Item #	-	-	MY5X-802	MY10X-803	MY20X-804	-	-	MY100X-806
Manufacturer Part #	-	-	378-802-6	378-803-3	378-804-3	-	-	378-806-3
Numerical Aperture (NA)	-	-	0.14	0.28	0.42	-	-	0.70
Field Number	-	-	24	24	24	-	-	24
Working Distance (WD)^b	-	-	34.0 mm	34.0 mm	20.0 mm	-	-	6.0 mm
Parfocal Length^b	-	-	95.0 mm			-	-	95.0 mm
Design Tube Lens Focal Length^c	-	-	200 mm			-	-	200 mm
Coverslip Correction^e	-	-	-	-	-	-	-	-
Diameter^b	-	-	34.0 mm			-	-	34.0 mm
Length^b	-	-	66.0 mm	66.0 mm	80.0 mm	-	-	94.0 mm
Threading	-	-	M26 x 0.706^g			-	-	M26 x 0.706^d

The field number definition can vary between manufacturers. The field number for these objectives represents performance over the full operating wavelength range with no vignetting over the entire field of view.
These dimensions are defined in the drawing below.
For information on compatibility between tube lenses and objectives, see the Magnification & FOV tab.
An SM1A12 adapter allows an M25 x 0.75 objective to be used with our SM1 lens tubes.
A coverslip correction given as a range of thicknesses indicates that the objective has a correction ring (see Objective Tutorial for details).
An SM1A3 adapter allows an RMS objective to be used with our SM1 lens tubes.
An SM1A27 adapter allows an M26 x 0.706 objective to be used with our SM1 lens tubes.

Dimensional Drawing

Olympus Objective Dimensional Drawing

Objective Identification

Note: These microscope objectives serve only as examples. The format of the engraved specifications will vary between objectives and manufacturers.

Types of Objectives

Thorlabs offers several types of objectives from Nikon, Olympus, and Mitutoyo. This guide describes the features and benefits of each type of objective.

Dry or Oil-Immersion Objectives
This designation refers to the medium that should be present between the front of the objective and the cover glass of the microscope slide. Dry objectives are designed to work best with an air gap between the objective and the specimen, while oil-immersion objectives require the use of a drop of immersion oil (such as MOIL-30) between and in contact with the front lens of the objective and the cover glass. Oil immersion is required in order to achieve numerical apertures greater than 1.0. Note that if an oil immersion objective is used without the oil present, the image quality will be very low. Our oil-immersion objectives are presented here.

Plan Achromat and Plan Apochromat Objectives
"Plan" designates that these objectives produce a flat image across the field of view. "Achromat" refers to the correction for chromatic aberration featured in the lens design. These objectives have chromatic aberration correction for two wavelengths and spherical aberration correction at one wavelength. Plan achromats produce their best images for green light. The apochromat objectives on this page have chromatic aberration correction for three wavelengths and spherical aberration correction at two wavelengths. In white light, the plan achromats give satisfactory images for color photomicrography, but the results are not as good as objectives that feature better correction, such as plan apochromats or the plan fluorite objectives below.

Plan Fluorite Objectives
Plan fluorite objectives, also referred to as plan semi-apochromats, plan fluorescence objectives, or plan fluors, also produce a flat image across the field of view. Plan fluorite objectives are corrected for chromatic aberrations at two to four wavelengths and spherical aberrations at three to four wavelengths. In addition to being corrected for more wavelengths, plan fluorite objectives generally offer reduced aberrations between the design wavelengths relative to plan achromats. These objectives also work well for color photomicrography.

Magnification Color Codes

Immersion Media Color Codes

Glossary of Terms

Magnification
The magnification of an objective is the lens tube focal length (L) divided by the objective's focal length (F):

M = L / F .

The total magnification of the system is the magnification of the objective multiplied by the magnification of the eyepiece or camera tube. The specified magnification on the microscope objective housing is accurate as long as the objective is used with a compatible tube lens focal length.

Numerical Aperture (NA)
Numerical aperture, a measure of the acceptance angle of an objective, is a dimensionless quantity. It is commonly expressed as

NA = n_i × sinθ_a

where θ_a is the maximum 1/2 acceptance angle of the objective, and n_i is the index of refraction of the immersion medium. This medium is typically air, but may also be water, oil, or other substances.

Parfocal Length
Also referred to as the parfocal distance, this is the length from the top of the objective (at the base of the mounting thread) to the bottom of the cover glass (or top of the specimen in the case of objectives that are intended to be used without a cover glass). For instances in which the parfocal length needs to be increased, parfocal length extenders are available.

Working Distance
This is the distance between the front element of the objective and the specimen, depending on the design of the objective. The cover glass thickness specification engraved on the objective designates whether a cover glass should be used.

Click to Enlarge
This graph shows the effect of a cover slip on image quality at 632.8 nm.

Field Number
The field number corresponds to the size of the field of view (in millimeters) multiplied by the objective's magnification.

FN = Field of View Diameter × Magnification

Coverslip Correction and Correction Collar (Ring)
A typical coverslip (cover glass) is designed to be 0.17 mm thick, but due to variance in the manufacturing process the actual thickness may be different. The correction collar present on select objectives is used to compensate for coverslips of different thickness by adjusting the relative position of internal optical elements. Note that many objectives do not have a variable coverslip correction (for example, an objective could be designed for use with only a standard 0.17 mm thick coverglass), in which case the objectives have no correction collar.

The graph to the right shows the magnitude of spherical aberration versus the thickness of the coverslip used, for 632.8 nm light. For the typical coverslip thickness of 0.17 mm, the spherical aberration caused by the coverslip does not exceed the diffraction-limited aberration for objectives with NA up to 0.40.

2X Objective Performance Graphs

4X Objective Performance Graphs

Click to Enlarge
Mouse Retina Imaged Using the Thorlabs TL4X-SAP

Click to Enlarge
These images of a mouse kidney tissue sample show a comparison between the Thorlabs TL4X-SAP objective (left) and an objective with 4X magnification and 0.13 NA from a major manufacturer (right). The two images were taken using a 1.4 MP scientific camera under the same illumination conditions.

Click Here to Download High-Resolution, 16-Bit TIFF Files (ImageJ Recommended for Viewing)

When viewing an image with a camera, the system magnification is the product of the objective and camera tube magnifications. When viewing an image with trinoculars, the system magnification is the product of the objective and eyepiece magnifications.

Manufacturer	Tube Lens Focal Length
Leica	f = 200 mm
Mitutoyo	f = 200 mm
Nikon	f = 200 mm
Olympus	f = 180 mm
Thorlabs	f = 200 mm
Zeiss	f = 165 mm

The rows highlighted in green denote manufacturers that do not use f = 200 mm tube lenses.

Magnification and Sample Area Calculations

Magnification

The magnification of a system is the multiplicative product of the magnification of each optical element in the system. Optical elements that produce magnification include objectives, camera tubes, and trinocular eyepieces, as shown in the drawing to the right. It is important to note that the magnification quoted in these products' specifications is usually only valid when all optical elements are made by the same manufacturer. If this is not the case, then the magnification of the system can still be calculated, but an effective objective magnification should be calculated first, as described below.

To adapt the examples shown here to your own microscope, please use our Magnification and FOV Calculator, which is available for download by clicking on the red button above. Note the calculator is an Excel spreadsheet that uses macros. In order to use the calculator, macros must be enabled. To enable macros, click the "Enable Content" button in the yellow message bar upon opening the file.

Example 1: Camera Magnification
When imaging a sample with a camera, the image is magnified by the objective and the camera tube. If using a 20X Nikon objective and a 0.75X Nikon camera tube, then the image at the camera has 20X × 0.75X = 15X magnification.

Example 2: Trinocular Magnification
When imaging a sample through trinoculars, the image is magnified by the objective and the eyepieces in the trinoculars. If using a 20X Nikon objective and Nikon trinoculars with 10X eyepieces, then the image at the eyepieces has 20X × 10X = 200X magnification. Note that the image at the eyepieces does not pass through the camera tube, as shown by the drawing to the right.

Using an Objective with a Microscope from a Different Manufacturer

Magnification is not a fundamental value: it is a derived value, calculated by assuming a specific tube lens focal length. Each microscope manufacturer has adopted a different focal length for their tube lens, as shown by the table to the right. Hence, when combining optical elements from different manufacturers, it is necessary to calculate an effective magnification for the objective, which is then used to calculate the magnification of the system.

The effective magnification of an objective is given by Equation 1:

(Eq. 1)

Here, the Design Magnification is the magnification printed on the objective, f_{Tube Lens in Microscope} is the focal length of the tube lens in the microscope you are using, and f_{Design Tube Lens of Objective} is the tube lens focal length that the objective manufacturer used to calculate the Design Magnification. These focal lengths are given by the table to the right.

Note that Leica, Mitutoyo, Nikon, and Thorlabs use the same tube lens focal length; if combining elements from any of these manufacturers, no conversion is needed. Once the effective objective magnification is calculated, the magnification of the system can be calculated as before.

Example 3: Trinocular Magnification (Different Manufacturers)
When imaging a sample through trinoculars, the image is magnified by the objective and the eyepieces in the trinoculars. This example will use a 20X Olympus objective and Nikon trinoculars with 10X eyepieces.

Following Equation 1 and the table to the right, we calculate the effective magnification of an Olympus objective in a Nikon microscope:

The effective magnification of the Olympus objective is 22.2X and the trinoculars have 10X eyepieces, so the image at the eyepieces has 22.2X × 10X = 222X magnification.

Sample Area When Imaged on a Camera

When imaging a sample with a camera, the dimensions of the sample area are determined by the dimensions of the camera sensor and the system magnification, as shown by Equation 2.

(Eq. 2)

The camera sensor dimensions can be obtained from the manufacturer, while the system magnification is the multiplicative product of the objective magnification and the camera tube magnification (see Example 1). If needed, the objective magnification can be adjusted as shown in Example 3.

As the magnification increases, the resolution improves, but the field of view also decreases. The dependence of the field of view on magnification is shown in the schematic to the right.

Example 4: Sample Area
The dimensions of the camera sensor in Thorlabs' 1501M-USB Scientific Camera are 8.98 mm × 6.71 mm. If this camera is used with the Nikon objective and trinoculars from Example 1, which have a system magnification of 15X, then the image area is:

Sample Area Examples

The images of a mouse kidney below were all acquired using the same objective and the same camera. However, the camera tubes used were different. Read from left to right, they demonstrate that decreasing the camera tube magnification enlarges the field of view at the expense of the size of the details in the image.

Click to Enlarge
Acquired with 1X Camera Tube (Item # WFA4100)

Click to Enlarge
Acquired with 0.75X Camera Tube (Item # WFA4101)

Click to Enlarge
Acquired with 0.5X Camera Tube (Item # WFA4102)

Posted Comments:

r07941046 (posted 2018-12-24 22:47:26.263)

Are RMS60X-PFC and N60X-PF suitable for 1550 nm wavelength? Thank you.

nbayconich (posted 2018-12-26 01:08:54.0)

Thank you for contacting Thorlabs. Transmission at 1550nm will be relatively low for both objectives and may not be suitable. Since not all of our vendors provide transmission plots to share I will reach out to you directly to discuss the ideal working range for these products.

deokkihong (posted 2018-07-30 22:48:15.767)

Hi, I want to analyse a system including objective lens with opitics program like 'Code five' or 'Zemax' . Is there any supplement data of RMS10X and RMS20X for 'Geometric optics program'?

YLohia (posted 2018-07-31 09:56:33.0)

Hello, thank you for contacting Thorlabs. These two objective lenses are made by Olympus and, unfortunately, they do not offer Zemax (or other ray tracing) files.

marc.miousset (posted 2018-04-02 08:40:00.973)

Hi, Please, I need mount RSM10X, on SMIL1 or other, and they trhead, does'n work. What ring works in the catalog Thorlabs. Thanks Have nice day Marc

YLohia (posted 2018-04-03 03:27:06.0)

Hello Marc, thank you for leaving feedback on our website. I wasn't able to find anything in our catalog with the part number SMIL1 -- are you referring to SM1L10? If that is the case, you can use the SM1A3 or SM1A3TS adapters to mate the RMS10X to any of our internally SM1-threaded components (for e.g., SM1L10).

vinithamr (posted 2017-06-12 19:56:18.133)

hello, I want to couple free space laser beam of diameter 1mm into optical fiber P1-780PM-FC(NA 0.12). How to choose the objective lens for that especially NA and EFL. Pls help.

tfrisch (posted 2017-06-26 02:38:06.0)

Hello, thank you for contacting Thorlabs. I will reach out to you about both geometric approximations for fiber coupling as well as equations needed to match the diffraction limited spot size to the mode field diameter. In the latter, I will need to know the wavelength of the source.

libaikui (posted 2017-02-10 17:19:50.68)

Can the objectives be used in magnetic field ~1T? Is there any effect on the position of the spot, transmission, etc?

tfrisch (posted 2017-02-16 11:49:16.0)

Hello, thank you for contacting Thorlabs. We don't have a way to test these objectives under various magnetic fields, but I will reach out to you directly about your application.

naveedullah1984 (posted 2016-10-07 10:54:40.953)

How can I calculate the spot size for an objective lens. I am using a collimated 635 nm Laser light.

jlow (posted 2016-10-07 04:42:44.0)

Response from Jeremy at Thorlabs: The focused spot size is going to be dependent on the input beam diameter and how Gaussian your input beam is. For a Gaussian beam (M^2=1), you can use the diffraction limited spot size formula (4*λ*f)/(pi*input beam size) to estimate the spot size.

egorglad (posted 2016-09-27 07:33:55.527)

Hello. Please need help. I need datashet on a RMS20X. I need data such as dispersion of lens, lenses type, Coating of lens. It's need for calculate my optical systen.

jlow (posted 2016-09-29 04:17:21.0)

Response from Jeremy at Thorlabs: I will contact you directly about this.

user (posted 2016-09-26 16:52:05.52)

Question to tfrisch Posted Date:2016-09-01: In overview tab, you mention "They are designed to have high transmission, particularly at UV wavelengths" give us a hint on how we should understand the description?

tcampbell (posted 2016-10-12 08:48:43.0)

Response from Tim at Thorlabs: Thank you for your feedback. These objectives have high transmission in the near UV, visible, and near IR wavelength ranges. We have updated the web to be more clear about this.

user (posted 2016-08-26 18:46:41.743)

Hello, I am looking for a microscope objective to perform spatial filtering. This will be used in conjunction with a 325nm laser. The Nikon N40X-PF, infinity corrected seems to be a suitable option as it is designed for UV applications but I cannot find its transmittance at my wavelength of interest. thank you

tfrisch (posted 2016-09-01 10:23:07.0)

Hello, thank you for contacting Thorlabs. Unfortunately, Nikon has not shared transmission data with us. We do give UV transmission curves for our Microspot Objectives here: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3271&tabname=Graphs

stefano.minardi (posted 2016-02-23 14:48:52.153)

Dear Sirs, I'm planning to use the objective RMS40X to focus a 10W CW laser beam at a wavelength of 1550 nm. Is the damage threshold of the objective high enough for this application? Thank you and best regards Stefano Minardi

besembeson (posted 2016-03-08 01:46:43.0)

Response from Bweh at Thorlabs USA: 10W is too high for these objectives. Olympus recommends limiting the power to under 100mW for collimated light.

user (posted 2015-12-17 11:43:32.007)

Hello, does any one have experience placing these objectives into a cryostat (LN2, 77 K)?

besembeson (posted 2015-12-18 11:58:31.0)

Response from Bweh at Thorlabs USA: We don't have test data on these objectives under such conditions at this time. I will check if Olympus and Nikon can provide this feedback.

gtn75 (posted 2015-11-19 19:52:07.67)

I want to know where are the principal planes of this objective.

besembeson (posted 2015-11-20 02:25:21.0)

Response from Bweh at Thorlabs USA: The effective focal length is 20mm, and the working distance of course is 16mm. Nikon doesn't provide the back focal length of the objective.

jesmondhong (posted 2015-03-25 00:12:16.623)

The working distance of the infinity corrected objective is the distance from the sample to the lens. what about the focal length? Is the focal length measured from the lens as well?

besembeson (posted 2015-04-21 07:07:29.0)

Response from Bweh at Thorlabs USA: Not really. The working distance is from the surface of the objective. The focal length is from a lens position inside the objective housing, useful for magnification, spacing constraints and numerical aperture calculations.

user (posted 2015-03-09 15:02:07.91)

Hello, I am interested in the Olympus RMS4X but I need additional information on the field of view, is it possible to get it ? Do you have the Zemax "black-box" design for this objective ? Thank you in advance. Olivier

besembeson (posted 2015-03-26 01:14:17.0)

Response from Bweh at Thorlabs USA: Olympus doesn't provide such models for these objectives and we don't have a black box design. If there is any specific property you are interested in for this objective, let me know.

c.j.lee (posted 2015-03-06 11:35:50.093)

Hi, We are making a Raman microscope using the Olympus objectives (4x and 10x). For quite some time, we were trying to eliminate what appeared to be a large spurious signal. On changing the objectives from the ones we purchased to a Leica objective from an old microscope, suddenly, the signal noise reduced substantially. Our conclusion was that the objectives (including the Leica) are emitting autoflourescence. Do you have any recommended objectives for Raman spectroscopy? Ones that are known to use pure fused silica, rather than doped glasses?

besembeson (posted 2015-03-25 05:04:35.0)

Autofluorescence is possible depending on the excitation wavelengths in your application. The RMS4X and RMS10X have low NA, which may not be suitable for Raman applications, where collection efficiency, spatial resolution and depth of focus all become important. Optimal design is a reflective objective which eliminates all chromatic aberrations with excellent spatial resolution in a broad spectral range. You may consider one of our series of Schwarzschild designed reflective objectives, such as the LMM-40X-UVV which can be found at the following link: http://www.thorlabs.de/newgrouppage9.cfm?objectgroup_ID=6933.

simon.stehle (posted 2015-02-13 13:51:44.64)

Dear Sir or Madam, we intend to use your "RMS20x" to focus the Laser Light (532 nm, cw). Can you give a statement about the maximum Power acceptable for the RMS20X? Thanks, Simon.

besembeson (posted 2015-02-26 09:57:38.0)

Response from Bweh at Thorlabs USA: We don't have a maximum acceptable power level but Olympus recommends limiting the power input to <100mW for collimated light and <20mW for focused light.

matthias.beck (posted 2014-05-20 09:35:51.07)

Dear Sir/Madam, i would like to ask for further specifications with regard to the microscope objective lense 20X Olympus Plan Achromat Objective, 0.4 NA, 1.2 mm WD. It is written, that the transmission is in the visible range. What kind of glass is the lense made of and how long is the glass. (I am interested in the dispersion added to a short laser pulse). Further, how far does the transmission range reach with regard to upper and lower end of the visible wavelength range, i.e. is the lense suitable for a wavelength range 500 nm - 1400 nm, or will there be severe cutoff in the IR range. I would appreciat if you could send me some specs / data. Regards, M. Beck

besembeson (posted 2014-05-21 04:41:48.0)

A response from Bweh Esembeson at Thorlabs USA. Thanks for contacting us. The RMS20X is manufactured by Olympus and at this time, we have limited information about detail specifications. For example we know that the transmission at 834nm is about 67% but we don't have data about the transmission up to 1400nm or the thickness of the lenses. You may consider contacting Olympus for more detail information. I hope this helps and let me know please if I can further assist you.

bill.wilson (posted 2014-05-11 19:48:32.7)

At UWA have many microscopes - Nikon, Leica and Olympus, looking for optics for a variety of purposes. Very painful being treated as new buyer each time you go on line. I know what I want. Open your catalogue for experienced microscopists. We are the people who know what we want and will be spending money. You will not snare a new buyer on-line. My staff would be sacked if they fell for online tricks!

besembeson (posted 2014-05-15 09:21:50.0)

Response from Bweh E at Thorlabs: Thanks for contacting Thorlabs. We have all of our products online and our prices are posted. If there is a system that you are interested in and you would like to receive more information or pricing, please feel free to contact me directly and I can assist you in this. We recently started a special catalog for Life Science researchers. This is can be found at the following link, including our V21 catalog: http://www.thorlabs.com/support.cfm?section=7&viewTab=4&catalogGroup=LS Let me know if there are any questions. If you need someone to call you to discuss your interests further, provide me with a phone number and a convenient time to call and I will do that for you.

samavial (posted 2014-03-25 21:18:49.553)

Which is (or how could I calculate it) the maximun possible entrance NA for the RMS40X if I use a condenser lens before it (focaliced at the WD)? And, which lens would fix the best for that if my light (colimated) beam has a diameter of about 8mm? Thanks. Sara.

besembeson (posted 2014-03-27 04:35:55.0)

Response from Bweh E at Thorlabs: Thanks for contacting Thorlabs. The numerical aperture of this objective is 0.65 and the working distance is 0.6mm. So it is best to use a condenser with a matching or smaller numerical aperture to get most signal through the objective. I will send you separate email about your application to discuss the second part of your question.

basili (posted 2014-01-28 06:49:57.283)

I would like know the beam spot size from achromatic objective RMS4X, when 3.6mm collimated beam is injected to it a 638nm wavelength. Or which exactly formula that can be applied to calculate beam spot size generated by RMS4X?

jlow (posted 2014-01-28 08:09:15.0)

Response from Jeremy at Thorlabs: The RMS4X is diffraction limited at 638nm so you can use the diffraction limited spot size calculation to estimate the focused spot size. Focused spot size = (4*wavelength*focal length)/(pi*input beam diameter). This assumes a well collimated round Gaussian beam.

dlaminiphumla.p (posted 2013-10-11 02:14:43.87)

what is the attenuation (power loss in dB) of the RMS4X

tcohen (posted 2013-10-14 11:44:00.0)

Response from Tim at Thorlabs: Because it’s a multi-lens system, the losses from the AR coated optics will compound to make the attenuation more wavelength dependent than a single lens with a BBAR coating. A sample transmission plot shows 80% at 400nm, rising to >95% at 500-700nm and back down to 80% at ~850nm. I’ll contact you to discuss your particular wavelengths and provide a sample curve.

basili (posted 2013-06-24 07:11:22.883)

Would you please let me know the effective focal length of RMS4X achromatic objective.

sharrell (posted 2013-06-24 10:25:00.0)

Response from Sean at Thorlabs: Thank you for using our feedback tool. The effective focal length of the RMS4X objective is 45 mm. This specification and others may be found by clicking on the Specs tab on the page. I’ll look to see how we might make this information more prominent.

tcohen (posted 2012-06-21 15:54:00.0)

Response from Tim at Thorlabs: Thank you for your interest in our objectives! We currently do not have operating temperature specs for these objectives. I will contact you to find out which objective you are interested in data for so that we may provide more information.

elizabethdoesphysics (posted 2012-06-19 13:34:42.0)

Are there specs stating the operable temperature range for these objectives? We are considering heating a sample and viewing it with an objective. However, the objective may get hot during the process (it takes about 1.5 days at a temperature of about 50 to 60 degrees C). Would these microscope objectives tolerate such use?

bdada (posted 2012-01-23 09:56:00.0)

Response from Buki at Thorlabs: Thank you for using our feedback forum. An objective with 10, 20, 40X, etc and no Focal Length designation will typically have an EFL equal to the "Tube Length" divided by the magnification. Typical tube length is 200mm so for a 10X objective the EFL is 200/10 = 20mm EFL. This is the approximate EFL and NOT the working distance. Working distance for a 10X objective would be somewhere around 15mm. There are other common tube lengths but the more common ones are 200mm and 160mm. Please contact TechSupport@thorlabs.com if you have any questions.

david.szwer (posted 2012-01-20 13:09:43.0)

Dear ThorLabs, I am considering buying one of the infinity-corrected microscope objectives for use as an output collimator for an optical fibre. The output beam radius is very important, and I can calculate it using the fibre's numerical aperture, and the objective's effective focal length. However, I can't find details of the effective focal lengths for these objectives. Is there another way to calculate the beam size using the information you give? Best regards, David.

jjurado (posted 2011-03-18 10:35:00.0)

Response from Javier at Thorlabs to Lehmann: Thank you for contacting us with your request. The entrance aperture for these microscope objectives can be calculated using the following formula: EA = 2 * EFL * tan [arcsin(NA)]. So, for an objective like the RMS4X, the entrance aperture is 9.1 mm. I will contact you directly for further support.

Lehmann (posted 2011-03-17 13:05:06.0)

I have a question about these microscope objectives. I need to focus a laser to a certain spot size. The given values for the NA is based, I assume, that one fills the input lens. In order to calculate the effective NA for an input TEM00 beam, I must know the input size corresponding to the limiting aperture, but I do not see this listed. Perhaps this the effective focal length times the listed NA. Please pass along information that will allow me to calculate the focal spot size from the wavelength and input beam diameter, assuming a TEM00 beam.

Thorlabs (posted 2010-07-27 17:55:26.0)

Response from Javier at Thorlabs to kearly500: Thank you for your feedback. We do not have concise values for the damage threshold of these lenses. However, as a guideline, Olympus recommends limiting the power input to <20mW for focused light and <100mW for collimated light.

kearly500 (posted 2010-07-27 11:40:40.0)

Hi, Im wondering what the damage threshold is for the RMS40X. Were using it to fiber couple a 2W solid state laser at 532 nm, and I wanted to know if we need to attenuate beforehand.

Adam (posted 2010-04-15 09:32:19.0)

A response from Adam at Thorlabs to Albert: While it is possible to use the RMS threaded objectives with the DCC1645C, I think we need more information about your application before we confirm. We would need to know information about your object size and distance. I will email you directly to get this information. On a side note, to connect the RMS threaded objective to the DCC1645C, one would need to use a SM1A3(SM1 to RMS threaded adapater), and a SM1A9(SM1 to C-mount threaded adapter).

albert (posted 2010-04-15 06:14:07.0)

Dear Sirs, We are going to develop a digital microscopic imaging system by using your DCC1645C, MAX203, BSC102 and objective lens(RMS Series). I would like to know if it is possible to install RMS lens to DCC1645C and get the microscopic image. If the answer is not, how we can integrate such kind of imaging systm by using your existing products. Look forward to getting your advice ASAP. Albert Lin Unique Instruments Co., Ltd. 6F., No.15, Lane 12, Xingzhong Rd., Nangang District, Taipei City 115, Taiwan (R.O.C.) Web: www.unii.com.tw email: albert@unii.com.tw Tel:+886-2-2654-6101 Fax:+886-2-2654-6102

Adam (posted 2010-03-24 11:35:49.0)

A response from Adam at Thorlabs: At this time, Olympus does not provide us with information on the focal shift of these lenses. Since we cannot get this information from Olympus, we cannot provide concrete numbers. The RMS40X is designed more for red and blue wavelengths, so the shift from 650-750nm will be slightly larger than that of a typical objective, 3-4um. The focal shift of the C340TME-B lens is 20um over the range of 650-750nm. I noticed that an email address was not provided. If you have further questions, please feel free to respond to the feedback or send an email to techsupport@thorlabs.com.

user (posted 2010-03-23 11:23:28.0)

I am interested in the typical focal shift around 650-750nm. In addition I would like to know the maximum diffraction limited range around 700nm. I am thinking about this objective or the C340TME-B lens, to collect light from a point like ligth source in the above mentionned wavelength regime. Thanks

klee (posted 2009-10-19 18:26:23.0)

A response from Ken at Thorlabs to plouis: These objectives are primarily designed for blue and red region. However, they still have about 83% transmittance at 800nm so they should work.

plouis (posted 2009-10-19 16:45:10.0)

I would like to know if it possible to use these lenses for coupling 830 nm light (photons from SPDC) into SM (and MM) fibers using your fiber launch system.

technicalmarketing (posted 2009-03-22 08:33:38.0)

Response to jbao from Inge at Thorlabs: These microscope objectives can be mounted to our lens tubes using an SM1A3 adapter.

jbao (posted 2009-03-21 17:07:00.0)

do you have tube lens for these objectives?

technicalmarketing (posted 2008-02-07 09:14:45.0)

In response to dutertes inquiry, we have contacted our optics department. Unfortunately, Olympus does not provide us with transmission curves for their objectives. I apologize that we cannot be of more help to you. Perhaps Olympus would be willing to provide that information if you contacted then directly.

duterte (posted 2008-02-05 04:40:14.0)

Could you please tell me what are the transmissions for the infinity-corrected microscope objectives UIS2 : - 4X Microscope Objective, 18.5 mm WD - 10X Microscope Objective, 10.6 mm WD - 20X Microscope Objective, 0.4 NA, 1.2 mm WD - 40X Microscope Objective, 0.65 NA, 0.6 mm WD At 1064 nm and if it’s possible at 1550 nm. With best regards, Charles DUTERTE

technicalmarketing (posted 2007-10-25 15:12:01.0)

We are currently in the process of updating this page to inlcude new items. A link to microscopy tools will appear in the family image shortly.

acable (posted 2007-10-25 14:32:36.0)

It would be nice to link the Microscopy Tools section to this product page.

Thorlabs Super Apochromatic Objectives

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Axial color describes the shift in the image plane across the operating wavelength range of the 2X super apochromatic microscope objective. For more performance graphs, see the Super Apochromatic Objectives tab above.

Objective Case
Case	Lid: OC2M25 Canister: OC22

Infinity-Corrected Super Apochromatic Design
Ideal for Imaging or Focusing Laser Light
M25 x 0.75 Threading
Designed for a Tube Lens Focal Length of 200 mm

Thorlabs offers super apochromatic microscope objectives with 2X or 4X magnification. The objectives are designed to provide diffraction-limited performance over a wide field of view with no vignetting over the entire field. The high numerical aperture (NA) of these objectives makes them ideal for widefield imaging and light-starved environments. The super apochromatic objective design provides axial color correction at three wavelengths and a broadband AR coating improves transmission over the 350 - 700 nm range. For more details on these objectives, please see the Super Apochromatic Objectives tab above.

These microscope objectives are ideal for applications such as traditional microscopy, confocal imaging, and fluorescence imaging. They are suitable for use in a variety of imaging modalities, including epi-illumination, oblique illumination, and brightfield imaging.

Each objective housing is engraved with the item #, magnification, NA, wavelength range, and working distance. The housings have external M25 x 0.75 threading and are designed for a tube lens of focal length 200 mm. To use the objectives with a different thread standard, please see our M25 x 0.75 thread adapters.

The TL2X-SAP and TL4X-SAP objectives have parfocal lengths of 95.0 mm and 60.0 mm, respectively (see the Specs tab for complete specifications). To use these objectives alongside each other, we offer the PLE351 Parfocal Length Extender to increase the parfocal length of the TL4X-SAP objective from 60.0 mm to 95.0 mm.

Olympus Plan Achromat Objectives

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Protective Accessories
Case	Lid: OC2RMS Canister: OC22
Aluminum Cap	RMSCP1

Infinity-Corrected Plan Achromat Design
Ideal for Imaging or Focusing Laser Light
RMS (0.800"-36) Threading
Designed for a Tube Lens Focal Length of 180 mm
45.06 mm Parfocal Length

These infinity-corrected, imaging microscope objectives for visible wavelengths provide 4X, 10X, 20X, or 40X magnification. With their high numerical apertures (NA) and large magnifications, they are suitable for focusing or collimating laser light. These Olympus objectives are ideal for imaging applications due to their diffraction-limited performance across the entire visible spectrum. Alternatively, they can be used to focus light to a diffraction-limited spot, enabling efficient coupling of monochromatic or broadband light into a waveguide or fiber. Each of these objectives is suitable for use in brightfield microscopy, while the RMS10X, RMS20X, and RMS40X also offer excellent performance in darkfield imaging.

Their designation as plan achromats indicates that they are flat field and aberration corrected at two different wavelengths in the visible spectrum, leading to better spherical and chromatic corrections and superb field flatness. These achromatic objectives have an ultra-wide antireflection coating and standard RMS threading. To use these objectives with a different thread standard, please see our RMS Thread Adapters.

These Olympus objectives have a parfocal length of 45.06 mm (see the Specs tab for complete specifications). To use these objectives alongside other manufacturer standards, such as Nikon objectives with a 60 mm parfocal length, we offer Parfocal Length Extenders. For instance, the PLE152 Extender can be used to increase the parfocal length of an Olympus objective from 45.06 mm to 60 mm.

Olympus Plan Fluorite Objectives

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Protective Accessories
Case	Lid: OC2RMS Canister: OC22
Aluminum Cap	RMSCP1

Infinity-Corrected Plan Fluorite Design
Ideal for Imaging or Focusing Laser Light
RMS (0.800"-36) Threading
Designed for a Tube Lens Focal Length of 180 mm
45.06 mm Parfocal Length

These infinity-corrected, imaging microscope objectives for visible and NIR wavelengths provide 4X, 10X, 20X, 40X, or 60X magnification. Plan Fluorite objectives, also called a plan semi-apochromat, are corrected for four wavelengths. These are well suited for color photomicrography. The RMS60X-PFC features variable coverslip correction; it has a rotating correction collar that changes the distance between the objective elements, allowing the coverslip correction to be adjusted from 0.11 mm to 0.23 mm.

All of these objectives are excellent for brightfield microscopy, while the RMS10X-PF, RMS20X-PF, RMS40-PF, and RMS60X-PFC objectives are also excellent for DIC microscopy. These objectives use standard RMS threading. To use these objectives with a different thread standard, please see our RMS Thread Adapters.

Nikon Plan Fluorite Objectives

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Protective Accessories
Case	Lid: OC2M25
Case	Canister: OC22 (4X & 10X) OC24 (20X, 40X, & 60X)

Infinity-Corrected Plan Fluorite Design
Ideal for Imaging or Focusing Laser Light
M25 x 0.75 Threading
Designed for a Tube Lens Focal Length of 200 mm
60 mm Parfocal Length

The Nikon Plan Fluorite Objectives provide 4X, 10X, 20X, 40X, or 60X magnification. They are designed to have high transmission in the UV to NIR wavelength range and to produce flat images across the field of view. These multi-purpose objectives can be utilized for brightfield microscopy, fluorescence microscopy, and polarization-sensitive observations. The N10X-PF, N20X-PF, N40X-PF, and N60X-PF objectives are also good for both darkfield and DIC microscopy.

Of all the objectives featured on this page, these Nikon plan fluorite objectives are the most compatible with the ITL200 Infinity-Corrected Tube Lens and the tube lenses in DIY Cerna Systems. These objectives use M25 x 0.75 threading, which can be converted to other thread standards using Thorlabs' selection of M25 x 0.75 adapters.

These objectives are designed for use from -18 °C (0 °F) to 60 °C (140 °F) and are not recommended for use at extreme temperatures.

Mitutoyo Plan Apochromat Objectives

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Protective Accessories
Case	Lid: OC2M26 Canister: OC24

Long Working Distance
Infinity-Corrected Plan Apochromat Design
M26 x 0.706 Threading
Designed for a Tube Lens Focal Length of 200 mm
95 mm Parfocal Length

Thorlabs offers Mitutoyo Plan Apochromat Objectives with 5X, 10X, 20X, or 100X magnification. These plan apochromat objectives are corrected at three wavelengths to provide a flat field of view, free of chromatic aberration. The long working distance provides a wide space between the lens surface and the object. These objectives are ideal for machine vision applications or any application that requires some space between the objective and the sample.

The objective housings are engraved with the magnification and the numerical aperture and have external M26 x 0.706 threads. The objectives can be integrated into an SM1 lens tube system with the use of an SM1A27 adapter. For additional M26 x 0.706 threaded adapters, please see our Optical Component Thread Adapters guide. These objectives do not feature adjustment to correct for cover glass thickness and should be used without a cover slip.

These Mitutoyo objectives have a parfocal length of 95 mm (see the Specs tab for complete specifications). To use these objectives alongside other manufacturer standards, such as Nikon objectives with a 60 mm parfocal length, we offer Parfocal Length Extenders. For instance, the PLE351 Extender can be used to increase the parfocal length of an Nikon objective from 60 mm to 95 mm.

View All »Matching Part Numbers

Imaging/Focusing Microscope Objectives, Dry

Did You Know?

Dimensional Drawing

Objective Identification

Types of Objectives

Glossary of Terms

M = L / F .

NA = ni × sinθa

FN = Field of View Diameter × Magnification

Magnification and Sample Area Calculations

Magnification

Using an Objective with a Microscope from a Different Manufacturer

Sample Area When Imaged on a Camera

Sample Area Examples

Thorlabs Super Apochromatic Objectives

Olympus Plan Achromat Objectives

Olympus Plan Fluorite Objectives

Nikon Plan Fluorite Objectives

Mitutoyo Plan Apochromat Objectives

NA = n_i × sinθ_a