Advanced Photography at Cardonald College - Glasgow 2002/2003

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Lenses

Whatever camera you use, the lens is one of the most important parts of it. Regardless of the recording media, be it large, medium or 35mm format film or a digital CCD sensor. The quality of the lens will determine the end result. An expensive digital camera with a low quality lens will not give better results than a cheap 35mm compact. On the other hand, a traditional or digital SLR using a high quality lens will give superb results on the same 35mm film or CCD sensor.
Most SLRs come with a standard 50 or 55 mm focal length lens. But there are many different formats. Telephoto, Wideangle, Macro, fisheye, Zoom. For general use a zoom lens that ranges from 28/200 mm will be the best to use. It gives a range from wideangle (28mm) to standard (50mm) to tele (up to 200mm). There are however some drawbacks: minimum focussing distance is usually around 150 cm and the lowest aperture setting ranges from 3.8 at 28mm to 5.6 at 200mm. This means that when using slow films in low light conditions shutter speeds will be to slow for the camera to be used hand-held, and a tripod must be used.

Aperture Also called Stop or Diaphragm. This is an adjustable hole at the back of the lens. Its working is similar to the iris of the eye, and it is used to compensate for different light conditions and controls the brightness of the light that reaches the film. Each stop or setting is represented by a f-number.1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 44, 64. Each f-stop value is 1.4x (V2) larger, meaning that f8 lets through twice as much light as f5.6. The lowest number represents the largest opening. Together with shutter speed (see SLR) the aperture controls the amount of light that reaches the film.

Depth of field Another important function of the Aperture is control of depth of field. This basically is the amount of foreground to background sharpness. The lower the aperture the smaller the depth of field. This can be used effectively to highlight a subject by using a large aperture to make the background appear out of focus. For maximum depth of field and thus maximum sharpness, in for instance landscapes, use a high aperture.

Some Lenses. A collection of lenses. From the left: 80/200mm macro manual focus zoomlens. 100mm Nikon manual focus. Autofocus 28/200mm Sigma zoomlens. 28mm wideangle manual focus lens.

Chapters

• Home
• Equipment
• SLRs
• Other Formats [1] - [2]
• Lenses
• Filters
• lighting
• Developing
• Printing
• Project [1] - [2]