Camera Lenses Explained and In-Depth Review
Your camera lens will ultimately determine the kind of photos you can take with your camera. You might have a camera with variable lenses such as a DSLR or a fixed lens such as a point and shoot. Either way, your lens determines what kind of shots your camera is capable of taking.
What does the lens of a Camera Do?
In basic terms, the camera lens is there to focus the light received onto the sensor of your camera and this is what forms the image that you capture. Having the right lens is imperative to take the best, high-quality images. There are many lenses on the market and each has their own pro and cons when it comes to performance and what they do.
Standard lenses are meant to produce natural images, in other words, they will look the same as what you would see through the human eye. Macro lenses, on the other hand, are designed for the photographer to take close-ups with. They offer great sharpness as well as contrast.
Telephoto lenses will provide the photographer with a very high magnification level and are perfect for long distance shooting and filming. Wide angle lenses are those that allow you to get a larger amount of picture into a scene than your standard lens, some can take up to 180-degree shots.
Finally, you get your specialist lenses, these are those that are specifically designed lenses for portrait and creative photography and some will tilt, shift or give you a very soft-focus. You can also use these types of lenses to enable you to capture light, such as infrared, that is not the norm.
What do the Numbers mean on a Camera lens?
The numbers on a camera lens refer to the focal length of your lens. A 18mm lens is a wide-angle lens and a 55mm lens is one that has been zoomed in. The lens number show you how zoomed in you are on an object and it is, in essence, the distance between the lens and the camera’s sensor.
How does a Camera zoom Work?
A zoom is generally when the lens of your camera will move further away from the sensor and the camera body. Although there are some zooms that adjust inside the camera body and you cannot physically see the zoom. There are two different types of zoom on your point and press cameras and they are optical and digital zooms, and they work radically different from each other.
In point and shoot cameras the amount of zoom available is laid out using the “X” to show how much you get. It will also tell you how much optical and digital zoom you can expect from your camera with optical ranging from 3x to 30x, digital zoom can go up to 160x in some point and shoot cameras.
DSLR cameras, on the other hand, have interchangeable lenses with different zoom capacities, these unlike the point and shoot variety do not list their zoom capability in “X” zoom, instead they list the focal length available on the lens you are using.
Optical zoom is the increase of the focal length of the lens. By moving the lens further from the image sensor, the zoom will increase and you will only get a small portion of the scene you are looking to capture, zooming in on your subject and magnifying it.
The zoom on optical zooms is usually smooth which means you can stop the zoom at any time between the top level zoom and the least or no zoom. However, there are those that will limit you to certain stops along the way to full zoom.
This is a zoom where the camera will shoot a photo and then crop and magnify it to give you a close-up. The problem with this type of zoom it often leads to the image being degraded and not very good with extreme pixelation.
With DSLR cameras you get interchangeable lenses. This means you can get a lens with wide-angle capacity or zoom capacity. If the original camera lens does not suit your needs you can always buy an additional lens with a great zoom capability.
As we said previously, the zoom on a DSLR lens is not marked with an “X” but rather with the focal length of the lens. It is reasonably easy to work out what zoom it offers though. You take the maximum focal length available and divide it by the minimum length, this will give you the equivalent “X” zoom of your lens.
Some of the zoom lenses can be very heavy and require a tripod when using it to avoid “hand shake” effect on your photos. It is important to note that there are some negatives when using a zoom. Slower shutter speed as the camera will take longer to focus, this could lead to blurred images or worse, missing the all-important shot.
Zooms also create more noise when they are used. If you set your lens at the maximum zoom, you could end up with an image that has purple edges, ruining your photo. Another problem you could encounter is pincushioning where the left and right edges of your image are stretched out, or you find you have some horizontal lines across your image.
What is the Focal Length of a lens?
Focal length is the description of your camera’s lens. It is not the length of your lens itself, but rather a measurement of the distance between your lens and the sensor of your camera. This will determine how large, or small the image will be that you are wanting to capture.
If you have a short focal length, your angle of shot will be wider and you will have a much lower magnification. This is typically for wide angled shots that will take in the entire scene and not a close up of a specific object, however, if you are going to be using a zoom then the focal length will be a lot longer and the angle of view will give you a much higher level of magnification.
Having the correct lens is crucial to your DSLR camera. Most come with a standard 35mm lens, however, with DSLR cameras you can upgrade your lenses and also opt for high zoom lenses. The point and shoot cameras come with standard lenses that cannot be interchanged and usually with both optical and digital zoom capabilities.