Normal lenses and digital cameras

One of the factors that determines what is a standard lens is the size of the film or sensor in relation to the focal length of the lens. As most digital cameras have a sensor size that is smaller than a 35 mm frame, normal lenses for these cameras tend to have focal lengths shorter than 50 mm. This is even true for the SLR digital cameras that use the same lenses as the film camera version. To accurately compare the perspective of digital camera lenses, look for values that indicate the lens's '35 mm comparative' focal length. This converts the actual lens size to its equivalent on a 35 mm film camera.

In addition, knowing the Lens Multiplication Factor for a specific DSLR camera will enable you to calculate the difference in angle of view that results from using a sensor that is smaller in physical dimensions than a 35 mm frame. For instance, the multiplication factor for Nikon DSLR cameras is 1.5. This means that if I attached a lens that would be considered standard when shooting film - 50 mm - it will provide the angle of view equivalent to a 75 mm lens (50 mm x 1.5 = 75 mm) when used with a Nikon DSLR camera. This means that if I need a lens that will work as a normal lens on a Nikon DSLR then you will need to select a wider than normal lens to suit, i.e. a 35 mm lens on a digital DSLR has the same angle of view as a 52.5 mm lens on a film body.

Use the Lens Multiplication Factors listed in Table 15.1 as a guide to the angle of view changes with different lens and body combinations.

Table 15.1 The angle of view of lenses changes when they are attached to digital camera bodies which use a sensor that is smaller than a 35 mm film frame. Camera manufacturers commonly publish Lens Multiplication Factors to help users determine the changed angle of view compared to how it will appear when the lens is used with a film body. This table details the Lens Multiplication Factor for common camera models.

Digital Camera and Digital Photography

Digital Camera and Digital Photography

Compared to film cameras, digital cameras are easy to use, fun and extremely versatile. Every day there’s more features being designed. Whether you have the cheapest model or a high end model, digital cameras can do an endless number of things. Let’s look at how to get the most out of your digital camera.

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