Saturday, August 18, 2007

Camera Lens (Important parts of the Camera)

As far is camera is concerned from my last post What is the Best Camera or Digital Camera to Buy" I think it is time for us now to look after the Lenses.
What is Lens? Lens is the most important part of the camera, yes it is!!! because without this you cannot capture good photos. Just for an example, Imagine a person without sunglasses with 450/450 or more of eye grade, how they see images. (Note: All Lens Images are from Nikon)

Let talk about lens basic.

Cost and Quality
Camera lenses cost from a few pence to tens of thousands of dollars, yes some lenses are more expensive than camera , but all do basically the same job of making an image on the film or sensor. You can even take pictures without a lens using a pinhole camera. Some high-budget advertising campaigns have been shot this way, using large sheet film, giving results you would never guess came from a pinhole (in some cases the client didn't either.) At least one photographer has won an advertising award with an image literally taken using the bottom from a bottle. If you have the creativity you can work in many different ways. However in general, expensive lenses are likely to produce higher quality results.

Most of us use lenses made for photographic use, either on cameras with a fixed lens or with those that take interchangeable lenses.

Many pros will have spent several times as much on lenses as they have on the camera. But even the cheapest lenses on disposable cameras can produce good pictures.

Prime Lenses and Zooms

Photographic lenses come in two main types: fixed focal length (prime lenses) and zooms. Zoom lenses let you alter the focal length - and thus the angle of view that the picture takes in - while remaining focussed at the same distance.

Focal length

The focal length of a simple lens is the distance from its centre to the sharp image it gives of a distant object. This and the film size determines the angle of view that the lens gives on film (or sensor.) With a SLR camera (Single Lens Reflex) the viewfinder image is also created by the lens and will change according to the focal length of the lens in use. Non-SLR cameras with interchangeable lenses may show different white light frames for the different lenses.

Wide Angle Lenses

Short focal lengths compared to the sensor give a wide angle of view and are usually called wide-angle lenses. On 35mm cameras, any lens of 35mm or less is a wide angle lens, with those of around 24mm or less being called ultra-wide.

Standard Lenses

Lenses with a focal length around the same size as the sensor diagonal give a moderate angle of view and are called standard lenses. On 35mm cameras these are between 40mm and 55 mm.

Telephoto Lenses

Those lenses with a long focal length give a narrow angle of view. In the early days of photography they were known as long focus lenses. Lens designers soon started to use a trick called telephoto design to make these lenses shorter, and we now call all long focus lenses 'telephoto lenses' - most but not all are. Short telephoto lenses - around 70-105mm focal length for 35mm - are sometimes called portrait lenses, as they are great for 'head and shoulders' pictures. 200mm is probably the most common length for a telephoto now, with birders and some sports photographers favouring much longer glass - perhaps 400 to 600mm

35mm equivalents

35mm cameras dominated photography from the 1960s to the turn of the century and many photographers still think of focal lengths in terms of their equivalents on the 35mm format. So a 7.6mm focal length lens on a consumer digital camera may be referred to as a '39mm equivalent' - in other words it gives the same angle of view as a 39mm lens would give on the 35mm format.

Zoom lenses

A zoom lens can have different focal lengths, usually with a ring (or less commonly a slide) to move to alter the focal length. They are designed to keep in focus when the focal length is changed. When zoom lenses became popular in the 1970s, they were all telephoto lenses, often covering the range 70-210mm; some people still assume that zoom lenses are telephotos. My favourite zoom is a 12-24mm wide-angle, and there are some zooms that go from wide-angle to telephoto.

With smaller formats it is much easier to design zoom lenses with an extreme range. Zooms for 35mm are normally limited to a ratio of longest to shortest focal length of about 3:1, while for consumer digital cameras, 6:1 is not unusual

Zoom or Prime Lens?

Generally affordable zoom lenses have smaller maximum apertures than most fixed focal length lenses.

Prime lenses are generally lighter than zoom lenses, but a zoom lens will possibly replace two or three prime lenses, and be lighter, cheaper and less bulky than three lenses.

Prime lenses usually have less distortion than zoom lenses.

When photographing a rectangular subject, the image almost always will either bulge slightly out in the middle giving a barrel effect, or slightly in, resembling a pincushion. Lenses with 'good drawing' are those that have low distortion. The effects of distortion are usually only noticeable with subjects with straight lines - such as most buildings, seldom with portraits etc.


Dunitz Sandrino said...

Camera lens is the backbone for any camera. There is a huge varety of quality camera lenses in Dubai which come in affordable rates.

Dunitz Sandrino said...

Well written post with all the details on camera lenses in Dubai! Camera lenses vary and its the buyer's choice to go for camera lenses based on his or her photo needs.

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