So, you've chosen your new DSLR camera, but now you need lenses to go with your new system. Trust me, the choices and terminology can make the whole thing seem quite daunting! The flexibility offered by DSLR systems is wonderful, but it's of no use if you don't understand the details.
Fortunately, this camera lens buying guide should help you decipher the lingo!
The focal length of a lens simply refers to the angle of view that it will cover. Smaller numbers mean a wider angle will be captured, while larger numbers will have a smaller angle of view captured, but allow for bringing distant objects closer.
Two types of lenses are available: Zoom and prime. A zoom range will cover the distance between two extremes (such as 70-300mm), while a prime, or fixed, lens only covers a specific angle of view (such as 50mm).
Just to add to the confusion, these numbers don't always mean what they say! Many entry-level and consumer-level DSLR cameras have a cropped format sensor, commonly known as APS-C. This means that all lens distances need to be multiplied by 1.5 or 1.6 (depending on the manufacturer).
For example, an 18-55mm lens used on a cropped format camera will equate to a 28-90mm angle of view. Obviously, this is useful in creating more of a telephoto lens, but users lose out at the wide-angle end of the lens. Fortunately, most major camera manufacturers have solved this problem, and they produce specific wide-angle lenses designed for crop frame cameras.
Here is a list of the major manufacturers' names for specific APS-C lenses:
- Canon: EF-S
- Nikon: DX
- Pentax: DA
- Sony: DT
- Sigma: DC
- Tamron: Di-II
- Tokina: DX
Olympus calls its cropped format Four Thirds, and the crop factor is two (a 50mm lens will become a 100mm lens). This system is exclusive to Olympus.
Many of these manufacturers also make a standard range of lenses which will work on APS-C, film, and full frame cameras. APS-C specific lenses, however, won't work on film or full frame cameras. Most lens manufacturers only make lenses that fit their own cameras, but Sigma, Tokina, and Tamron make lenses to fit a variety of different manufacturers' cameras. Out of these three, only Sigma makes its own cameras.
Next, consider the maximum aperture allowed by the lens. This will be written on your lens, either as F8, f/8, or 1:8. Prime lenses will only have one aperture, whereas zoom lenses tend to allow you to drop to apertures in-between two readings, depending on your focal length (such as f3.5/4.5).
A smaller "f" number means that the lens has a larger maximum aperture and can therefore allow more light to reach the sensor. This will allow you to shoot in lower lighting conditions without flash. A larger aperture, such as f2, will also allow you to achieve a shallower depth of field, which is particularly useful for making one element in a photo sharp.
With the exception of Pentax and Olympus, which have incorporated image stabilization into their camera bodies, manufacturers offer lenses with image stabilization (IS). These lenses help to reduce blur caused by camera shake. IS is particularly useful when using telephoto lenses, as these are longer and heavier than other lenses and are difficult to hold steady. IS also allows for steady, sharp shots in lower lighting conditions. Each lens manufacturer uses a different acronym for IS in its lenses:
- Canon: IS
- Nikon: VR
- Panasonic and Samsung: OIS
- Sony: OSS
- Sigma: OS
- Tamron: VC
Prime Vs. Zoom Lenses
Zoom lenses obviously are far more flexible, covering a larger focal distance in one lens. The downside is that they weigh far more than prime lenses, tend to have slower maximum apertures, and can often have a slight loss of image quality if they cover a very large focal length. Prime lenses are sharper, lighter, and designed for specific purposes.
A lot of diffrent types of prime (or fixed) and zoom lenses are available. Some of the most popular ones include:
- Standard Lenses. Both fixed and zoom standard lenses exist. A fixed standard lens is widely regarded as a 50mm, while a standard zoom lens covers a range from a very gentle wide-angle to a slight telephoto, such as the 18-55mm kit lens that comes with most APS-C cameras. A standard lens is extremely useful.
- Wide-Angle Lenses. Typical wide-angle zooms for APS-C cameras range from 10-22mm, while 16-35mm would be the norm for a full frame camera. You'll need a wide-angle lens if you have an interest in landscape or architectural photography, as they allow for a much wider angle of view than the human eye and other camera lenses.
- Telephoto Lenses. A telephoto lens allows you to zoom closer to your subject, making it ideal for photographing wildlife or sports. Typical telephoto lenses tend to range from 70-300mm.
- Superzoom Lenses. These lenses are reasonably priced and cover a huge focal length range (such as 18-200mm). They're ideal for travel, as they're flexible enough to allow you to cut the number of lenses you must carry. However, when a lens is asked to cover such a large focal length range, a lot of quality can be lost, and the aperture range won't be great.
- Macro/Micro Lenses. These specialist lenses allow for extreme close-ups, and they work well for for photographing small objects such as flowers, insects, or jewelry. True macro lenses are a fixed focal length, usually 60mm or 100mm.
Auto and Manual Focus
Most modern lenses have the ability to switch between auto and manual focus, usually with a switch on the lens. More expensive lenses often have "ultrasonic" autofocus motors, which are fast and practically silent. They also allow for manual tweaking of the focus at any time and in any mode, without damaging the lens mechanism.
Cheaper lenses tend to be lightweight and made of plastic, but, if you pay a bit more, you'll have a lens that will last. More expensive lenses tend to be weather-sealed, which makes them more useable in difficult conditions. There are some lenses that are sturdy and well built, but you'll need to do your research.
When you chose a camera system to buy into, you shouldn't focus on the camera body alone and should really be making your decision based on the quality of the lenses available. Good quality glass counts!