How do dslr camera lenses work

Telephoto lenses are great for wildlife, portrait, sports, and documentary types of photography. Some can range between a wide-angle and a telephoto i. The trade-off with zoom lenses is the aperture. Because of the number of elements required in constructing these lenses, they have a limited ability to open up and allow in light.

A fisheye lens is a specialized, wide-angle lens that provides extremely wide images by changing straight lines into curves.

They range in focal lengths of between mm. These lenses obtain razor-sharp focus for subjects within the macro focus distance, but lose their ability for sharp focus at other distances. These lenses enable the photographer to obtain life-size or larger images of subjects like wasps, butterflies, and flowers.

If you are a professional wildlife photographer, sports photographer, or if you photograph the night sky and the stars, then a telephoto lens can be invaluable. Wide angles have a wider focal field, allowing you to essentially capture more of the scene in front of you than say a zoom lens.

For this reason, wide angles are perfect for photographing landscapes, as you can capture more of the scenery and create a much more vivid picture. A fisheye lens is basically an ultra-wide-angle lens, offering an enormous field of view. They are useful if you are photographing indoors or using your camera for design work.

An ultra-wide-angle lens can have a focal length as low as 8mm. In conclusion, there are different types of camera lens for almost any situation you could find yourself in as a photographer. Knowing which lens is best for what scenario, will set you on your way to becoming a much-improved photographer. Different types of camera lenses and when to use them. Focal Length. The ideal exposure depends on the size of the light-sensitive grains in the film.

A larger grain is more likely to absorb light photons than a smaller grain. The size of the grains is indicated by a film's speed , which is printed on the canister. Different film speeds are suited to different types of photography -- ISO film, for example, is optimal for shots in bright sunlight, while film should only be used in relatively low light.

As you can see, there's a lot involved in getting the exposure right -- you have to balance film speed, aperture size and shutter speed to fit the light level in your shot. Manual SLR cameras have a built-in light meter to help you do this. The main component of the light meter is a panel of semi-conductor light sensors that are sensitive to light energy. These sensors express this light energy as electrical energy, which the light meter system interprets based on the film and shutter speed.

Now, let's see how an SLR camera body directs the real image to the viewfinder before you take the shot, and then directs it to the film when you press the shutter button. There are two types of consumer film cameras on the market -- SLR cameras and " point-and-shoot " cameras. The main difference is how the photographer sees the scene.

In a point-and-shoot camera, the viewfinder is a simple window through the body of the camera. You don't see the real image formed by the camera lens, but you get a rough idea of what is in view.

In an SLR camera, you see the actual real image that the film will see. If you take the lens off of an SLR camera and look inside, you'll see how this works. The camera has a slanted mirror positioned between the shutter and the lens, with a piece of translucent glass and a prism positioned above it.

This configuration works like a periscope -- the real image bounces off the lower mirror on to the translucent glass, which serves as a projection screen. The prism's job is to flip the image on the screen, so it appears right side up again, and redirect it on to the viewfinder window. When you click the shutter button, the camera quickly switches the mirror out of the way, so the image is directed at the exposed film.

The mirror is connected to the shutter timer system, so it stays open as long as the shutter is open. This is why the viewfinder is suddenly blacked out when you take a picture. In this sort of camera, the mirror and the translucent screen are set up so they present the real image exactly as it will appear on the film.

The advantage of this design is that you can adjust the focus and compose the scene so you get exactly the picture you want. For this reason, professional photographers typically use SLR cameras. These days, most SLR cameras are built with both manual and automatic controls, and most point-and-shoot cameras are fully automatic.

Conceptually, automatic cameras are pretty much the same as fully manual models, but everything is controlled by a central microprocessor instead of the user. The central microprocessor receives information from the autofocus system and the light meter.

Then it activates several small motors, which adjust the lens and open and close the aperture. In modern cameras, this a pretty advanced computer system. In the next section, we'll look at the other end of the spectrum -- a camera design with no complex machinery, no lens and barely any moving parts.

As we've seen in this article, even the most basic, completely manual SLR is a complex, intricate machine. But cameras are not inherently complex -- in fact, the basic elements are so simple you can make one yourself with only a few inexpensive supplies. The simplest sort of homemade camera doesn't use a lens to create a real image -- it gathers light with a tiny hole.

These pinhole cameras are easy to make and a lot of fun to use -- the only hard part is that you have to develop the film yourself. A pinhole camera is simply a box with a tiny hole in one side and some film or photographic paper on the opposite size. If the box is otherwise "light-tight," the light coming through the pinhole will form a real image on the film.

The scientific principle behind this is very simple. If you were to shine a flashlight in a dark room, through a tiny hole in a wide piece of cardboard, the light would form a dot on the opposite wall. If you moved the flashlight, the light dot would also move -- light beams from the flashlight move through the hole in a straight line.

In a larger visual scene, every particular visible point acts like this flashlight. Light reflects off each point of an object and travels out in all directions. A small pinhole lets in a narrow beam from each point in a scene. The beams travel in a straight line, so light beams from the bottom of the scene hit the top of the piece of film, and vice-versa.

In this way, an upside down image of the scene forms on the opposite side of the box. Since the hole is so small, you need a fairly long exposure time to let enough light in. There are a number of ways to build this sort of camera -- some enthusiasts have even used old refrigerators and cars as light-tight boxes.

One of the most popular designs uses an ordinary cylinder oatmeal box, coffee can, or similar container. Its easiest to use a cardboard container with a removable plastic lid. Choosing a good camera design, film type and exposure time is largely a matter of trial and error.

But, as any pinhole enthusiast will tell you, this experimentation is the most interesting thing about making your own camera. To find out more about pinhole photography and see some great camera designs, check out some of the sites listed on the next page. But amazingly, all these designs -- from the simplest homemade box camera to the newest digital camera -- combine the same basic elements: a lens system to create the real image, a light-sensitive sensor to record the real image, and a mechanical system to control how the real image is exposed to the sensor.

And when you get down to it, that's all there is to photography! For more information on cameras, light, film and related topics, check out the links on the next page.

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Point-and-Shoot Homemade Cameras. There are two main types of DSLR lenses:. These lenses have a fixed focal length meaning that you have to move around more when framing your shot. However, they are generally a much faster lens and produce a sharper image. They also tend to be lighter which is great for travelling. These lenses have a varying focal length meaning that you can zoom in and out of a scene without having to move your location. Their flexibility can be a great asset although they tend to be much bigger and heavier than prime lenses.

Zoom lenses work on the idea that you are moving various lens elements inside the lens with relation to each other, whether by turning the zoom ring or pulling it forward or back. This changes the focal length and the magnification power of the lens. While prime lenses can help quickly develop your photographic skills, if you are not sure what kind of photography you will be doing, a zoom lens can be a great option. Within these two types of lenses there are several different more specialised lenses available.

Again, depending on the type of photography you are going to be doing will depend on which lens you should choose. These are the lenses that allow you to capture the tiny and intricate details of a scene. Often used in photographing small creatures such as ants and spiders, flowers as well as abstract images. Macro lenses can be purposely built prime or zoom lenses or they can be classed as macro simply because their closest focusing distance is short. The prime macro DSLR lenses will usually have a wider aperture and higher quality glass than their zoom counterparts, therefore producing a higher quality image.

A more affordable option if you are just getting started is to choose a lens that also has a macro function. This means that you can still do your everyday photography but if an occasion to capture a macro image comes along there is no need to change the lens. On the other hand, these types of lenses often have a longer focal length which will lower the quality of the image. If landscape photography is your thing then wide-angle lenses will be your bread and butter.

These lenses can often produce the images we find most visually fascinating as the lens can often distort what we see with our eyes in real life. This distortion, however, can be linked to the quality of the lens.

With the top wide angle DSLR lenses giving little to no distortion or chromatic aberration whereas the more affordable will see more. You are able to correct for this in editing software.

Wide angle DLSR lenses are available in both prime and zoom lenses with quality and affordability varying between the two. To determine which is for you, first you need to think about what you will be using it for. For example, if you are shooting portraits where you are able to easily move yourself around to capture the shot then a prime lens maybe best. However, if you are shooting a live performance where you are in a fixed position a zoom lens is probably going to be a better option.

If you are looking to photograph subjects from far away, then a telephoto lens is for you. They are generally lenses that have a focal length of 85mm or longer and like the other lenses they come in both prime and zoom.

When it comes to telephoto lenses though, it is the zoom lenses that are the most popular. This is because the situations that you generally need a telephoto lens require a little bit of flexibility and a zoom lens gives you that. Zoom telephoto lenses are particularly popular with sports and wildlife photographers as they are able to follow a subject without having to move much themselves.

These lenses also tend to have image stabilisation features which can be really helpful. It helps cut down any shaking or vibrations which become more obvious at longer focal lengths. Your general purpose, all-round and kit lenses are great when you are just starting out.

They allow you to do multiple different types of photography with just one or two lenses. This means you can figure out which kinds of photography you are most interested in before buying more specialised lenses. They are also popular with event and wedding photographers where the act of changing lenses can mean missing a potentially amazing shot.

These lenses are generally zoom lenses and because they are built to do multiple different things the overall image quality is not as high as a prime lens. However, there is a huge variety with some even having the ability to go from a wide angle to a long telephoto!

Obviously the more you want the lens to do the lower the image quality will be. Nevertheless, it is a great option if you are just starting out. If shooting portraits is your jam, then bagging yourself one of these lenses is a no brainer.

These lenses are generally prime lenses and so deciding on what kind of portrait you want to capture will help you decide which focal length to get. In general, a great starting point is to go for a focal length of around mm. This is because you can capture the soft beauty of a subject while still being able to add some drama and vibrancy.

These lenses are ultra-wide-angle lenses and produce a full degree radius image. These types of images are instantly recognisable as they distort the image and make everything look like its in a bubble.

These types of lenses are usually prime lenses. Also known as perspective-control lenses they allow you to shift and tilt the optical configuration of the lens relative to the sensor. Basically, it means that when you are photographing buildings you can correct for key stoning an effect that makes buildings appear like they are falling over. You can also adjust the depth of field without changing the aperture which can be helpful in landscape and product photography.

On the other hand, they only have the ability to focus manually. Not all lenses are perfect, and they all have varying degrees of distortion. Prime lenses usually have the least because they do not have to accommodate a range of focal lengths.

There are two main types of distortion to be aware of when choosing your lenses: Barrel distortion and Pincushion distortion. Barrel distortion is when the edges of the image look barrel-sized rather then straight. Pincushion distortion on the other hand is the opposite. It makes the edges bow inwards.