Camera Lenses for Machine Vision, C-Mount
- Fixed Focal Lengths from 3.5 mm to 75 mm
- Zoom Lens Covers 18 - 108 mm Focal Lengths
- Fast Lenses up to f/0.95
- Manual Focus and Aperture Control
- Design Formats as Large as 1"
- C-Mount Threaded is Compatible with our CCD and CMOS Cameras
Thorlabs' C-Mount Camera Lens offering includes lenses specifically designed for 1/2", 2/3", and 1" format sensors. Additionally, lenses can be used with smaller format sensors than they are designed for, but the image will be cropped, and will thus act like a longer focal length lens (see Crop Factor tab). These lenses are fully compatible with our compact high-resolution CCD and CMOS cameras, as well as many other cameras that feature C-Mount lens mounts and appropriately sized image sensors.
All lenses are fixed focal lengths (primes), aside from the MVL7000 zooming lens. Because of their simplified optical design, prime lenses commonly offer large maximum apertures and superior imaging characteristics. Zoom lenses, on the other hand, offer superior imaging flexibility. All prime lenses, aside from the MVL25, have locking focus and aperture rings.
We also offer High-Magnification Zoom Lenses, which offer magnification factors of 0.07 to 28.
The focal length of a lens determines the field of view of the camera system. The longer the focal length, the narrower the field of view. A general guideline is that a 50 mm lens on a full frame (35 mm) camera offers the same field of view as the human eye. As per the Crop Factor tab, the approximate human eye focal length equivalents for a few sensor formats are as follows:
|Sensor Format||Focal Length for Human Eye Approximate Field of View|
Image samples are shown for 1/3" and 1/2" sensor formats. The products are each roughly spaced in 8" (200 mm) increments. The first is a Polaris Mirror Mount on a Ø1" post placed 8" (200 mm) from the post that the camera is mounted on, the next is a balldriver for 1/4"-20 cap screws, third a Ø1.5" post, and lastly an RSP1X15 rotation mount on a Ø1/2" post and base. You will notice with wide angle lenses (short focal lengths), such as the MVL4WA, that the image exhibits barrel distortion. This is readily apparent with the mirror mount on a Ø1" post in the foreground as the post is actually straight.
1/3" Format Sensors
1/2" Format Sensors
MVL4WA: 4 mm Focal Length, 1/2" Format
5.2 mm Adjusted Focal Length
4 mm Focal Length
MVL8M23: 8 mm Focal Length, 2/3" Format
14.64 mm Adjusted Focal Length
11 mm Adjusted Focal Length
MVL16M23: 16 mm Focal Length, 2/3" Format
29.28 mm Adjusted Focal Length
22 mm Adjusted Focal Length
MVL25M23: 25 mm Focal Length, 2/3" Format
45.75 mm Adjusted Focal Length
34.375 mm Adjusted Focal Length
MVL35M23: 35 mm Focal Length, 2/3" Format
64.05 mm Adjusted Focal Length
48.125 mm Adjusted Focal Length
MVL50M23: 50 mm Focal Length, 2/3" Format
91.5 mm Adjusted Focal Length
68.75 mm Adjusted Focal Length
MVL75L: 75 mm Focal Length, 2/3" Format
137.25 mm Adjusted Focal Length
103.125 mm Adjusted Focal Length
Understanding apertures on camera lenses is important when selecting the appropriate lens for your application. The aperture is a ratio that tells you the amount of light that a lens can collect. The apertures on our C-mount lenses are adjustable to vary the amount of light let in. The more light a lens collects, the shorter the camera exposure needed. Camera lenses that can collect a lot of light are known as fast lenses as they can be used with shorter exposure times. In the specification tables below, the maximum aperture is given for each lens. This is what is important when judging how fast a camera lens is. Aperture is specified as a ratio f/#, such as f/1.4. "f" stands for the focal length of the lens, and thus, the smaller the denominator of this ratio, the more light that can be collected.
where f = focal length and d = aperture diameter (or, if the aperture is not circular, the diameter of a circular aperture with the same area).
Fast lenses are ideal for low-light conditions. For example, a 50 mm focal length lens with f/1.4 aperture has a 35.7 mm (50 mm/1.4) aperture. A slower lens would be a 50 mm lens with a f/2.8 maximum aperture, relating to a maximum aperture size of 17.9 mm (50 mm/2.8). To give a better perspective on what these aperture values mean, let's look at a table of full stop apertures. With each step to a smaller aperture (larger denominator), the light collected by the lens is cut in half.
While camera lenses are designed for a specific sensor format (size), they can be used with other format sensors. Using a larger sensor than the lens is designed for is typically undesirable as the lens is not capable of imaging across the whole sensor. Alternatively, using a smaller sensor is very common. In these cases, a Crop Factor is introduced. This Crop Factor is a ratio of the lens' design format diagonal length divided by the format diagonal length of the sensor used. The table below lists the approximate crop factors that are possible for 1/3", 1/2", 2/3", and 1" format sensors.
Sensor Format Used
|Lens Design Format|
The Crop Factor has a significant effect on the Field of View of each lens. Another term for Crop Factor is Focal Length Multiplier. When using a lens with a smaller format sensor, multiply the Focal Length Multiplier (Crop Factor) by the focal length of the lens. The lens will "feel" like the resulting product. For example, a 50 mm focal length lens designed for a 1" sensor will have the "feel" of a 100 mm focal length lens when used with a 1/2" sensor.
There are two sample images below. Both were photographed with an MVL4WA (f = 4 mm, 1/2" format). The left photograph was taken with a 1/2" format sensor and the right image was taken with a 1/3" format sensor. On the 1/3" format sensor, the 4 mm focal length lens will have a field of view roughly that of a 5.2 mm focal length lens. A table below the images lists the focal lengths "compensated" for 1/3", 1/2", 2/3", and 1" sensor formats.
1/2" Format Sensor
1/3" Format Sensor
MVL4WA: 3.5 mm Focal Length, 1/2" Format
3.5 mm Focal Length
4.6 mm Adjusted Focal Length