It’s important to note that CS mount lenses are not directly compatible with C mount cameras without an adapter. However, the reverse is possible, where C mount lenses can be used on CS mount cameras with the appropriate adapter.

CS-Mount lens

Ask students to look through coloured plastic sheets at different coloured objects, or to view drawings they make with coloured markers. Try outdoors. Depending on the colour of the object/marker and the colour of the filter, different features will be highlighted and will "disappear".

C-Mount specifications

CS mount lenses are widely available and specifically designed for surveillance and security applications. They offer a variety of focal lengths and lens options to meet different surveillance needs, including wide-angle lenses, telephoto lenses, and varifocal lenses. These lenses are typically used in closed-circuit television (CCTV) systems, video surveillance cameras, and other security applications.

CS-mount camera

The M12 mount has a flange focal distance of 12mm, which is the distance between the mounting flange (the metal ring that attaches the lens to the camera) and the image sensor. This short distance allows for the use of small and lightweight lenses, making it suitable for compact and portable camera systems.

CS-mount diameter

The M12 mount typically uses a threaded connection to secure the lens to the camera body. The lens is screwed onto the camera, and the threads ensure a secure and stable attachment. This type of mount is known for its simplicity and ease of use.

Explanation: The coloured plastic takes away (absorbs) some of the colours so only one colour reaches your eyes. e.g. a red sheet absorbs all colours except red, so everything has a red tinge. If something has no red in it, it will look black.

c-mount thread dimensions

The C mount has been widely used in the past for film cameras and is still utilized in modern digital cameras, particularly in the industrial and scientific imaging fields. However, in recent years, other lens mounts like the PL mount and EF mount have become more prevalent in professional cinema cameras due to their ability to handle larger sensors and heavier lenses.

Step by step activity to understand the phenomenon: Ask the students to put the red filter over their eyes. Then lay out coloured papers for them to look at (don't tell the students what colours they are). Ask what colours they appear through the filters. (The red paper will look red through the red plastic; the green paper will look black through the red plastic) Ask the students to take the plastic away so they can see the true colours of the papers. It is a very striking effect. Discuss: the paper only reflects some colours (that is why it appears a certain colour - the other colours are absorbed). If the plastic does not let the paper colours through, the paper will appear dark.

The CS mount is a standardized lens mount commonly used in the field of surveillance and security cameras. It is an extension of the C mount and is designed specifically for cameras with smaller image sensors.

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Idea for younger students: make a "dive" into the ocean by walking into a room with blue filter over eyes. Find fish taped to the wall.

Please note that in a class of students it is likely that one of them is at least partially colourblind (1 in 12 males are colourblind). As this is an activity distinguishing colours, these students will not be able to tell some colours apart and perceive some colours differently, although the activity will be no less interesting for them. The common red/green colour blindness means reds and greens (or colours containing reds and greens such as browns) look similar. More information at colourblindawareness.org and colorblindguide.com/post/the-advantage-of-being-colorblind.

c/csmount

Cto CS-Mount adapter

One of the key advantages of the C mount is its versatility. It can accommodate various lens types, including 16mm film lenses, 1-inch format lenses, and smaller lenses designed for compact cameras. Additionally, with the use of adapters, it is possible to mount C mount lenses on other camera systems, expanding the range of available lenses.

The CS mount has the same flange focal distance as the C mount, which is 17.526mm. This means that CS mount lenses can be used on C mount cameras by utilizing a C-CS mount adapter, but C mount lenses cannot be directly mounted on CS mount cameras without an adapter due to the shorter flange focal distance of the CS mount.

CS-Mount Telephoto Lens

The C mount uses a threaded connection to attach the lens to the camera body. The lens is screwed onto the camera, and the threads ensure a secure and stable attachment. The mount has a 1-inch diameter (25.4mm), which makes it relatively small compared to other lens mounts used in larger camera systems.

Coloured filters for astronomy studies: Astronomers use filters to look at images of stars and galaxies, to see the phenomena they are more interested in, while making other phenomena recede. Students can look at composite images of star nurseries, nebulae or galaxies, to see the cooler gas clouds (often imaged in red, so visible through the red filter) separated from the stars and higher energy wavelengths such as X rays (often imaged in blue, so visible through the blue filter). See this image of the sun through different filters (some wavelengths invisible to the human eye), and the sun's features that are highlighted with each filter: https://www.nasa.gov/sites/default/files/styles/full_width_feature/publ…

The CS mount uses a threaded connection, similar to the C mount, to attach the lens to the camera body. However, the thread diameter of the CS mount is smaller than that of the C mount, measuring 1/2 inch (12.5mm). This smaller size is another characteristic that distinguishes the CS mount from the C mount.

One advantage of the M12 mount is its wide compatibility with various lens types. Many lens manufacturers produce M12 lenses, offering a range of focal lengths and aperture options to suit different imaging needs. These lenses are typically designed for use with small image sensors found in compact cameras, surveillance systems, and other devices.

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Overall, the C mount remains an important and versatile lens mount, particularly in applications where compactness and flexibility are desired.

The C mount has a flange focal distance of 17.526mm, which is the distance between the mounting flange and the image sensor or film plane. This short distance allows for flexibility in lens design and makes it compatible with a wide range of lenses, including both prime lenses and zoom lenses.

Coloured filters for helping understand how other animals and some people see Through the filters the world looks tinted and some colours look the same, and give a sense of how some animals or people with colourblindness have a different view of colours. The color vision of dogs is similar to a person with deuteranopia (red-green color blindness). Red, yellow and green are perceived as one hue. Blue and purple are perceived as a second hue. Cyan and magenta are perceived as a neutral hue (grey).

The CS mount has a smaller back focal distance than the C mount, allowing for more space between the lens and the image sensor. This extra space is necessary to accommodate the smaller image sensors used in surveillance cameras. By moving the lens further away from the sensor, CS mount lenses are optimized for these smaller sensors and provide the appropriate focal length and coverage.

Notes for teachers on the complexity of this activity: Objects and filters are usually not pure emitters of one colour, so other colours nearby in the spectrum also bleed through, hence changing the final colour observed. In other words, for coloured acetate and construction paper, both the papers and the filters will allow some other colours of light through other than the colour it appears i.e. green paper will reflect yellow and blue light as well as green (they are next door on the colour spectrum), and a blue filter will allow some green light to pass - hence through a blue filter, green paper appears green and red paper appears black. Some blue items appear purple through the red filter. The red filter is not perfect - it passes some light of other wavelengths besides red. Purple is a mixture of red and blue light - it is a non-spectral colour (violet is a spectral colour next to blue). When objects emitting blue light are seen through our red filter, both red and blue light are perceived, which look purple.

The M12 mount refers to a standardized lens mount commonly used in the field of digital imaging. It is a small form factor mount primarily used in compact cameras, webcams, and other small electronic devices that require interchangeable lenses.

The C mount is a standardized lens mount used in the field of professional video and cinema cameras. It was initially developed by Bell & Howell in the 1930s for 16mm film cameras and later adopted by other manufacturers.

Coloured filters for ocean animal camouflage: Ask students to draw an undersea scene with coloured markers, making sure that they draw some brown or black seaweed or rocks, some red and black ocean animals, and some light blue or light-coloured ocean animals. Ask them to look through a blue filter at their scene, which mimics the lighting in ocean water (red light does not penetrate beyond 100m deep, whereas blue light reaches deeper ocean water, making the scene blue-tinted). In the blue light, which fish colours appear dark, and which fish show up lighter? Red-coloured fish will look dark, and look the same shade as black objects. Blue and lighter coloured animals show up more brightly and are easier to see. Ocean animals exploit this phenomenon to hide from predators: in the mid-water regions of the ocean, where only blue light penetrates, many ocean animals are coloured red or black, so that they can camouflage against dark algae and rocks or just appear dark in the water. Light colour penetration into water: https://s-media-cache-ak0.pinimg.com/736x/0c/c0/50/0cc050beb2c576415fd0… Colours of ocean animals by depth: https://oceanexplorer.noaa.gov/facts/animal-color.html