Lens

The Lens

Fixed or Interchangeable?

A Fixed lens is simply a lens that is permanently fastened to its camera as opposed to a system camera that allows you to change its lens easily. Fixed lenses are commonly found cameras aimed at consumers, from old box, TLR (the Mamiya C systems being the exception) and folding cameras, through the consumer range finders of the 70's and through to today's point and shoot film and digicams. There are certain advantages to having a fixed lens on your camera:

1. As no mechanism for changing lenses needs to be built into the camera design it can help keep the camera smaller and lighter.
2. In digital cameras a fixed lens means that there is less chance of introducing dust to the sensor surface.
3. Fixed lenses are designed for a specific camera model and so less compromises have to be made in the lens design.
4. Cost - if your camera comes with a fixed lens you don't have to worry amount buying a lot of additional glass to build a system.
5. Portability - a fixed lens should be enough for most situations you encounter so you have less accessories to carry and you will waist less time changing lenses.

Interchangeable lenses are more commonly found on cameras aimed at professionals and enthusiasts including large format, SLR (medium format and 35mm) and high-end range finder cameras. The advantages to interchangeable lenses include:

1. A larger range of focal lengths and specialties (shift, macro, etc.) are available than you are likely to find on any fixed lens camera.
2. Each lens can be designed for a specific kind(s) of working situations and specialties without the compromises a generalist fixed lens has to be designed for.
3. Longevity - you can upgrade your camera body without losing any investment you have made in additional lenses if your new camera choice is in the same family as your old camera.

Auxiliary lenses - if your camera has a fixed lens there are accessories available that allow you to enhance your fixed lenses range. These included close-up lenses that allow your camera to focus closer than it naturally can. They also include wide-angle attachments that allow your fixed lens to capture more of a scene than it otherwise could. They also include popular telephoto attachments that allow your fixed lens to reach further than it otherwise could. Telephoto attachments include extreme digiscoping lenses. Digiscoping is the practice of mounting a digicam on a spotting scope of telescope to create extreme focal lengths.

As with all photographic equipment, auxiliary lenses range in quality from the truly dreadful to the professional. Bear in mind that any auxiliary lens that you attach to your fixed lens is adding more glass between the subject and the film. As such it is bound to affect image quality and the amount of light passing through to the film plane. Cheap auxiliary lenses add horrible distortion and purple fringing to your shots. Auxiliary lenses are a compromise solution to extending the range of a fixed lens that can provide good results but there appear to be no bargains in this niche market place and you will get what you pay for,

Zoom or Prime?

In general, non-zoom lenses let in more light than zoom lenses, which allows you to take photos in more difficult situations.

Contrary to what many people think, Zoom lenses have no effect on perspective. All they allow you to do is to modify the cropping before you take the shot. This can add great flexibility, nevertheless. Zoom lenses are bulkier than fixed lenses, and they introduce an extra adjustment you must make before taking the picture. The vast majority of digital cameras come equipped with Zoom lenses.