How does a telephoto lens affect distant subjects?

A telephoto lens is designed to magnify distant subjects, allowing the photographer to capture details from a far distance that would otherwise be too small to discern with a standard lens. This lens not only brings distant subjects closer, making them appear larger in the final image, but it also compresses perspective. This means it can create a shallow depth of field, making the background appear closer to the subject than it actually is, which is a distinctive visual effect often used in photography to emphasize the subject.

This capability of magnification and perspective compression is what makes telephoto lenses popular for wildlife photography, sports photography, and portrait photography, where isolating the subject from the background is often desired. Such visual manipulation leads to a more pronounced subject against a blurred background, enhancing the subject's prominence in the frame.

The other options address effects not typical of telephoto lenses. For example, blurring distant subjects generally occurs with shallow depth of field, which is not an inherent feature of all telephoto lenses. Reducing subject size does not accurately describe the enlarging effect of telephoto lenses. Altering color perception is also not a characteristic that is specifically influenced by lens type, as color is primarily affected by lighting and sensor characteristics.