Different Types of Lenses for SLR Camera
The main advantage of using a DSLR camera is its ability to change lens. How do you choose a lens?
Lenses are categorized on the basis of 2 factors: the aperture opening, and angle of view.
On the basis of “Aperture opening“, SLR lenses are divided into 2 categories.
A lens that has got an f-number below f3.5 can be called as a fast lens. Let’s understand this with an example. The best example for a fast lens is Canon’s 50mm f1.8 lens. This is the cheapest fast lens available in the market. It costs around 100$. Normally, fast lenses are costly and heavy. But the above mentioned lens from canon is an exception.
For Canon’s 50mm f1.8 lens, maximum value of aperture opening can be calculated as:
50/1.8=27.78, at f1.8 50/4=12.5, at f4.0 50/8=6.25, at f8.0
From the above calculation, it is clear that lenses having lower f-numbers will have lager aperture opening as a result of which more light can enter into the camera and reach the sensor. Fast lenses are good for night photography, sports photography and for taking snaps in low light condition.
2. Slow lens
A lens that has got an f-number above f3.5 can be called as a slow lens. Here, larger f-number corresponds to smaller opening in the lens. So less light will be entering through the aperture. Slow lenses are preferred for landscape
photography. In the case of landscape photography, we need to bring more
objects in focus, which requires a higher f-number. Canon’s EF-s 18-55 f3.5-5.6 IS USM lens is a good example for a slow lens. The maximum f-number for this lens is f3.5 at 18mm and f5.6 at 55mm. This variation in f-number while zooming is not a good choice for low light photography.
On the basis of “Angle of View”, lenses are classified in the following categories:
1. Wide-angle lens
Wide-angle lenses are used for landscape photography. Since it has got a wide
angle of view, it can cover more area than a telephoto lens. Any lens which has got a focal length less than 35mm can be called as a wide-angle lens. The angle of view for a wide-angle lens will be 55 degree or more.
2. Super-Wide angle or Fish Eye lens
Super-wide angle lens or an Ultra-wide angle lens is one, which
has got a focal length of 24mm or less. The angle of view for an ultra
wide-angle lens will be 70 degree or more. The main advantage of an ultra
wide-angle lens is that you can get closer to the object and capture the image.
3. Telephoto lens
If you want to take the picture of a distant object then you can go for a telephoto lens, with a narrow angle of view. Wild life photographers use telephoto lenses. The focal length for a telephoto lens starts from 70mm. The angle of view will be 15 degree or less. An example for a telephoto lens is Canon’s 70-200mm f/4.0 L IS USM lens.
4. Super-telephoto lens
Bird photographers use Super telephoto lenses. The angle of view for a super telephoto lens is 8 degree or less. These are very costly and heavy when compared to other lenses. The focal length for such a lens starts from 300mm.
5. Macro lens
If you want to capture the minute detail of a flower or insect then you will have to use a macro lens. The minimum focusing distance for a macro lens will be small when compared to other lenses. This allows you to get closer to the object to take the snap. The image reproduction ratios for a macro lens will be 1:1 or higher. Canon EF 100mm macro USM lens is an example for a good macro lens.
6. Prime lens
A Lens having a fixed focal length is called as a prime lens,a nd its main advantage is better picture clarity. Most prime lenses are costly and bulky. Since it is a fixed focal length one, you will have to adjust the distance between yourself and the object to take the snap. Canon’s EF 50mm F/1.8 is an example for a prime lens. This lens has got a fixed focal length of 50mm.
7. Zoom lens
If you are not interested in changing your camera lens then you can go for a typical zoom lens. A zoom lens will have all basic focal lengths required for portraiture, landscape, wildlife and sports photography, but picture clarity will be less at some focal lengths. This is the main disadvantage of a zoom lens. Nikkor 18-200mm VR zoom lens is a good example for a zoom lens.