Role of Camera and Lens

Text By: Ruman Shrestha  |  Photo By: Purushottam Pokharel

Role of Camera and Lens

Learning level: - Basic
Learning time: - 20 minutes

I think, I don’t need to explain, what is photography and camera. Most of people better understand a small electronic device, which creates a JPEG file of image data is known as digital camera. Physically, there are many types of camera, such as ‘point-and-shoot’ camera, Bridge camera, SLR camera and Mobile version camera. It doesn’t matter how they look and how much price. The basic function of those cameras is to create data file of image. How does camera create image data file!? I’ll describe about this on another article in future.  In this article I would like to write something about SLR camera.

SLR denotes Single Lens Reflector. So now it’s simple to understand SLR camera is a camera which has a single lens. There is also TLR (Twin Lens Reflex) camera but here it doesn’t subject matter for this article. Every SLR camera has a single lens attached in it. In other words, all SLR cameras have main two parts, 1) camera body and 2) lens. The main point need to remember that all SLR cameras can be detached body and lens separately. What do they play different roles when we take photographs!? It’s very important to understand.  


Nikkor Lens

- The main job of the camera lens is, the reflected light rays from any object send inside the camera. There are so many glass lenses (optics) used inside the camera lens. Those lenses (optics) receive light rays of surrounding nature from brighter side then converge all those light rays at the other side. This way, at the certain distance all the light rays meet in single point and created the real image.

- Secondly, camera lens also controls how much light send inside the camera. To control light amount, a small mechanical unit made inside the lens which is called aperture.

- Another major function of the lens is control the angle of view. As per different types of lenses they produce fixed or variable angle of field view.

Having all these characteristics, camera lens cannot make an image data file itself. Camera lens can produce the real and virtual image which our ‘human’ eyes can see but that is only for viewing purpose. To make an actual image data file, the image sensor plays a main role which exists inside the camera body.


- There are many more function and electronic controls on the camera body than lens. Camera body also has a control function how much light send inside with different way.

- One of the main parts of camera body is image sensor, which stays exactly behind the lens attachment. Image sensor receives the real image with refracted light rays through the lens.

- Image sensor is made of silicon which has millions of pixel basis photodiodes inside it. The light sensitive silicon image sensor converts lights into electrical signals then output in digital numerical values which is also called binary digit system.

- All collected pixel basis numerical data by image sensor send to main image processor. The main image processor receives numerical data then aligns rows and columns sequence same as image sensor collected before.  After aligning data in rows and columns, a composite new pixel basis data developed with a specific ration in length and breadth, which is basically the first stage of image data. Then after such an image data further processed and purified to produce raw image data. Lastly, necessary compressed for an actual JPEG file and save it in memory card.

- Having the main image sensor and much more other functions, camera body cannot make an image data file itself. The camera body must be collaborated with lens mounting with it because the real image signal can be only projected by lens.

Conclusion: Having so much features and functions on Camera body and camera lens they cannot produce image data file itself solely. Producing an actual image data file is a jointly result of collaborating work of them. 

Ruman Shrestha

Ruman Shrestha

Hello! Professionally I’m photographer, Photoshoper, Illustrator and graphic designer. I had taken photography training with Photojournalism in 1996. I’m self-learned Photoshoper and Illustrator. I'm fully freelancer. I love to learn new tools of Photoshop and Illustrator then create various kinds of artwork and vector graphics in my free time. On long days vacation, I would like to travel and trek high-altitude area to celebrate my leisure time. I’ve deep interest in Nature photography. Landscape and Wildlife are my favorite subjects. Moreover, I like also birding and bird’s photography. I'm general member of 'Bird Conservation Nepal' too. I am the founder of TutsGallery. I’ve founded this website to share my knowledge and experience to new generation in photography. I hope, you’ll like this. If you also like to contribute such kind of knowledge and experience, I request you, start from today and contact me. Let’s enjoy photographing!

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