Camera Lens Repair Bristol
Camera Lenses - FAQs
This article covers the 10 questions I get asked most often about buying camera lenses. It includes What Lenses Do I need to Get Started? and What is a Lens Mount?
What is a fast lens?
A fast lens has a large aperture. Lenses with an aperture of f/2.8 or below are deemed to be a fast lens. The large aperture size means that you can use a fast shutter speed and still achieve a bright exposure. As you might expect fast lenses are popular for use in low light as they increase the possibility of being able to hand hold your camera to get a photo.
What is a kit lens?
Digital SLRs at the lower end of the price spectrum usually give you the option of buying the camera body on its own or with one or two lenses. The option that includes the lenses is commonly know as a kit. A kit that comes with one lens usually includes a wide angle lens. The quality of kit lenses can vary, but it is an economical way of getting started.
What is a tele converter?
A tele converter increases the focal length of a lens. It is a small piece of equipment that sits between a camera body and lens. Buying a tele converter is a much cheaper option then buying a long lens. Typical conversion factors are 1.5x and 2x. So a 2x tele converter can change a lens with a 200mm focal length into one with a 400mm focal length. There are two downsides to using tele converters. The first is that they reduce the amount of light reaching the camera sensor. The second is they can have a negative impact on picture quality.
What lenses do I need to get started?
A lot depends on the type of photography you are interested in and what your budget is. A standard suggestion is to start off with two lenses. One to cover wide angle subjects such as landscapes and a second lens to give you some form of telephoto capabilities. The beauty of taking the Digital SLR route is that you can build your camera system over time, adding lenses or improving lens quality as budget allows.
Is one brand better than another?
Canon and Nikon are the most popular brands, but I would not say that one brand is better than another. If your budget is unlimited I would suggest buying either a Canon or Nikon Digital SLR and then buying their best lenses to go with it. For the rest of us some form of compromise is required.
Why do the prices of lens vary so much?
Camera lenses can be broken down into different quality categories. Professional lenses offer better photo quality and normally better build quality too. Therefore these are more expensive. Lenses with extreme focal lengths push technological boundaries more, so these lenses also cost more.
What is an aperture?
An aperture is the hole that light passes through into the camera when the shutter is opened to take a picture. Using different aperture sizes has an impact on the way your photos will look.
What is a focal length?
The focal length of a lens is defined as the distance from the centre of its lens to its foca...
Common Lens Faults
There are seven common faults that a camera lens may suffer from. A lens may noticeably suffer from all of them or maybe just one of them. The degree to which the problem occurs will also vary from lens to lens.
Chromatic aberration adds a colour to the edges of an object. Purple is the colour that occurs most frequently. Therefore chromatic aberration is often referred to as purple fringing. I have also seen examples of chromatic aberration in blue and green.
Lens flare can easily ruin or detract from a great picture. It occurs when a light source, usually the sun, reflects off elements within the lens. This is more likely to be a problem with cheaper zoom lenses. Prime lenses are least likely to exhibit the problem.
Barrel Distortion is most noticeable in any photograph where there are straight lines. Therefore the easiest way to test for barrel distortion take a photo of a grid, newspaper or a brick wall. If the centre of the grid appears to bulge out towards you then the lens suffers from barrel distortion. This is similar to a fisheye effect.
Pincushion distortion is the opposite to Barrel Distortion with the centre of the image appearing to become more distant. It tends to crop up more with telephoto zoom lenses.
Vignetting is where the corners of a photo are darker. On occasion vignetting is used by the photographer to draw attention to the centre of the photograph. Normally it is unwanted.
Loss of Contrast
In general the quality of the lens you use will have little impact on the vividness of the colours produced ...