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The Lens Guide

Lenses are an essential part of your photography gear collection. Choosing the right lens for your project can make all the difference. Whether you’re looking at optics, weight, size, or even cost, be sure to familiarize yourself with the different types of lenses you can choose from. Below is your guide to lens terminology:


PRIME LENS:  A lens with a fixed focal length. When you look through it, you can’t change the magnification. Examples: 28mm, 50mm, 85mm, 135mm. Also referred to as a Fixed Focal Length Lens.

ZOOM LENS:  Also referred to as a Variable Focal Length Lens, when you look through it, you can change the magnification. Examples: 18-55mm, 24-70mm.

TELEPHOTO LENS:  A lens in which the physical length of the lens is shorter than the focal length. Often long-focal-length lenses (ex. 100mm, 200mm, 300mm) are referred to as telephoto lenses (although not always correctly).

FAST LENS:  A lens that has a large aperture which allows you to take photos in low lighting without a flash. Examples: 50mm f1.4, 85mm f1.2. Likewise, if someone is talking about “lens speed”, they are referring to the maximum aperture on that lens. You will also hear the term “slow lens” which is a lens with a smaller maximum aperture (usually above f2.8).

MACRO LENS:  A lens that allows you to focus at distances that are relatively closer than non-macro lenses and in some cases a lens designed specifically for close-up photography as a primary mission. Examples: 50mm 2.5 macro, 60mm 2.8 macro, 100mm 2.8 macro.  Keep in mind there’s no one commonly agreed upon definition of which lenses should be labeled ‘Macro’: you’ll actually find two flavors of lenses label macro:

 

FLAT FIELD LENS:  A lens that is designed to produce a more consistently flat field of sharpness from edge to edge. Generally used in lenses that are designed with Macro photography and ‘copy work’ as a primary mission.

 

CURVED FIELD LENS: most conventional lens designs allow more curvature of the image field as it approaches the picture edges. This can result in images that are sharper in the center and tend to get softer as you reach the sides.  Some curved field lenses have extra close focus distance capability built-in (and thus labelled ‘Macro’ by a manufacturer), but if they’re not a flat field lens primarily designed for macro then we label them as having a ‘Macro Feature’.


WIDE ANGLE LENS:  A lens that will make things appear further away than they do with normal vision, and will also allow you to cover a larger area in your photos. Used for indoor photography when space is limited, as well as outdoor photography when you need to capture a large area or landscape. Any lens with a focal length smaller that your camera’s standard or normal lens would be consider to be wide angle. Example: 20mm.

FISHEYE LENS: A wide-angle lens that takes a hemispherical image. Fisheye lenses produces a distorted image, convex in appearance, and cover a broad area of view. Focal lengths typically range from 16mm and lower. Examples: 8mm, 10mm.  

SOFT FOCUS LENS:  A lens that is designed to gently diffuse the overall image. Soft focus lenses are generally used when taking portraits. Example: 135mm 2.8 soft focus. Not to be confused with soft focus filters.

CAT LENS:  Also referred to as a mirror or reflex lens. Uses mirrors in it’s design to make larger focal length lenses smaller, lighter, and less expensive. Has a fixed aperture.

PORTRAIT LENS:  A lens that gives the best perspective for taking portraits. This will vary depending on the camera that you’re using. For example, if you’re using a 35mm film camera, it would be an 85mm or 105mm lens. If you’re using a 6×6 film camera, a 150mm would probably be your choice. Keep in mind that with a digital camera, there may be a magnification or crop factor, so the lens focal length choice might be a bit different.  Any Long/Tele lens can work as a portrait lens as long as you have enough room.

STANDARD LENS:  Also referred to as a normal lens. This would be considered to be the lens that gives you about the same perspective as normal vision. Nothing would appear any closer (or further away) than you would see it with your normal vision. This focal length will change depending on which type of camera that you use. If using a 35mm film camera, a 50mm lens would be considered as the normal lens, while a 75mm or 80mm lens would be considered normal when using a 6×6 film camera. When using a digital camera, the magnification or crop factor must be considered when determining a normal lens.

 

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One comment

  1. To clarify: A varifocal changes its focal length without regard to maintaining proper focus through its zoom range, requiring you to refocus as you “zoom” the lens. A proper zoom lens will maintain focus throughout its entire range of focal lengths.
    While it is not critical for still photography to maintain focus through zoom, it is exceedingly crucial in videography and cinematography.

    A normal lens for still photography is generally a focal length equal to about the diagonal of the format. Using the Pythagorean theorem on 6×6 for example: SquareRoot((6^2) + (6^2)) gives us 8.4 cm or 84 mm, which is close to 80mm.

    “normal” is partially arbitrary. If you know the size of the sensor, you can calculate “normal” and err toward the longer lens, as it will likely have better distortion characteristics.

    Macro really means that the image on the sensor is represented larger than it is in real life. Being able to focus closer is not necessarily macro.

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