A lens primer for beginning photographers
One of the questions I am often asked by new photographers is “What lens should I buy next?” The answer to this question is both simple and highly convoluted. It is a personal decision based on your needs, your photographic style and your budget. Between the marketing hype and the fan boy forum diatribes research on the internet can often be confusing. If you are just starting out in photography you should start by using your kit lens, the one that came with the camera. After you have taken your first thousand pictures or so you will have a better understanding about what type of lens will suit your subject matter and personal style. Along the way you should consult with fellow photographers who are producing the types of images that you envision yourself creating. Find out what lenses they are using and keep that in mind when you need to decide on your next lens. Consulting with the specialists at your local photography store can also help you with your decision. These professionals can lay out all the options for you and help you make the best decision based on your needs and budget.
Focal length – The focal length of a lens is usually expressed in Millimeters. The focal length determines the magnification or field of view at which it images distant objects. A shorter focal length will capture a wider the field of view (see wide angle lens) and a longer focal length will magnify or have a narrower field of view (see telephoto lens).
PHOTO; lens barrel with focal length
Aperture – Aperture refers to the opening in the lens diaphragm through which the light passes. The aperture is expressed in F- stops. Each full f stop represents either doubling or cutting in half the amount of light reaching the sensor depending on whether you are increasing or decreasing the f number. The smaller the f number the more light passes through the lens. A lens with a maximum aperture of f/1.4 will allow approximately 8 times more light than a lens with a maximum aperture of f/5.6. Conversely a larger f number allows less light to pass through the lens.
Zoom Lens – A lens with variable focal lengths is considered a zoom lens. These lenses are very popular because of their convenience. By changing the focal length or “zooming” you can compose an image in the camera without having to move closer or farther from the subject. This is handy when changing locations is inconvenient or unsafe. Using a zoom lens also reduces the number of times the photographer has to change lenses.
Prime Lens – A photographic lens with a fixed focal length (i.e.; 35mm, 50mm or 85mm) is known as a prime lens. Fewer lens elements along with a simpler design generally makes these lenses smaller, faster (wider maximum aperture) and sharper than zooms.
Kit Lens – A lens packaged in a bundle with a camera body. For APS sensors this is usually an 18 to 55 mm zoom lens. In general these lenses are entry level lenses, however some high end camera bodies will be “kitted” with a professional quality lens.
Normal Lens – A lens that reproduces a viewing angle that appears normal to a viewer. A lens with a focal length that is about equal to the diagonal measurement of the image sensor is considered normal and has a viewing angle of around 50°. For a DSLR with a typical APS-C or DX (cropped) sensor a lens with a focal length of around 28 to 35 mm would be a “normal” lens. A normal lens on a full frame DSLR would be approximately 50mm.
Telephoto Lens – A lens that has a narrow viewing angle is considered a telephoto lens. These lenses will make distant objects appear closer. These lenses are typically used for sports, nature and wildlife photography or any photography where it is inconvenient or unsafe to be closer to the subject. These lenses have a viewing angle of 30° or less. Some Super telephoto lenses will have a viewing angle of as little as 1-2°.
Wide Angle Lens – A lens with a wider than normal viewing angle is called a wide angle lens. Typical uses for wide angle lenses are for architecture and landscape photography. It is an essential lens for photographers who photograph the interiors of buildings.
Fisheye Lens – A fisheye lens is an ultra-wide angle lens that produces extreme distortion in the form of curved vertical and horizontal lines. There are two types of fisheye lenses. Circular fisheye lenses have an image that appears in a circle on the frame. Full frame fisheye lenses fill the frame, but have a narrower field of view. Fisheye lenses have become popular for extreme sports photography.
Portrait Lens – There will come a day when you will be told that you need to buy a portrait lens. Any lens can be used to make a portrait. However, when photographers today speak about a portrait lens they are usually referring to a lens with specific qualities. An “ideal” portrait lens will have a focal length which is slightly telephoto and a wide maximum aperture to capture shallow depth of field (selective focus). Short telephoto lenses create a more pleasing perspective for portraits without the distortion associated with wide angle lenses. In addition combining the telephoto with a wide aperture enhances the selective focus creating a more pleasing blur (Bokeh) of the background. For a cropped sensor camera the ideal portrait lens would have a focal length of 50 or 85 mm. For a full frame sensor an 85 to 100 mm lens would be ideal
All-in-one Lens – For travel and convenience a number of manufacturers offer lenses that combine both telephoto and wide capabilities. Lenses such as the Tamron 18-270mm have a 15 times zoom factor which is equivalent to a 28 to 400mm lens on a full frame or 35mm film camera. These lenses are great for travelers wishing to reduce the amount of gear they are carrying.
Fast Lens– Lenses with a wide maximum aperture such as f2.8 greater are considered fast lenses. These lenses allow photographers to shoot in low light conditions. More light on the sensor allows for a “faster” shutter speed reducing the chance of blurring the subject.
Pro Lens– Any lens that costs more than the value your current automobile. Kidding aside, the demands of professional photography require lenses that are superior in performance. Pro lenses incorporate high quality optical glass with a low refractive index and superior lens coatings for better color and contrast.
Quick Bio
Paul Dileanis is a professional photographer and photography instructor. Over the last 4 decades his work in photography has included still photography as well as motion picture and video work and run the gamut from weddings to underwater missile launches. He is currently teaching photography workshops through Silicon Valley Images and working for San Jose Camera and Video in Campbell, CA.
