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I see different types of lens in the market like prime, zoom, telephoto and macro. I'm not sure how many such types really exists and the functions/features of each.
Can someone share an explanation for this?
Also, what is the major difference between zoom and telephoto lens?
Think of those as qualifiers, not types because they are not mutually exclusive:
A number of these qualifiers can apply to a single lens but some combinations are rare or impossible. You cannot have a variable aperture prime since the focal-length of such lens is constant. Of course, the aperture can change if the lens is not fixed aperture but there is only one maximum. For a zoom, some are constant aperture, say like a 24-70mm F/2.8, which means that F/2.8 is possible at any focal-length. Compare this to an 18-55mm F/3.5-5.6 which can open to F/3.5 at 18mm but only to F/5.6 at 55mm.
Zoom and telephoto are completely orthogonal:
First we need to define “normal” as to focal length. This is because wide-angle and telephoto are referenced from this value. All cameras can be fitted with a “normal” lens. Such a lash-up delivers an angle of view of about 45⁰. We are talking about a camera that yields a rectangular image. The 45⁰ angle of view results when the camera is held horizontal (landscape). The camera images by allowing the lens to project an image of the outside world on the surface of film or digital sensor. Usually the image area (format) will be a rectangle. We measure this rectangle from corner to corner (diagonal measure). We mount a lens with a focal length about equal to this diagonal measure and the results are a “normal” image.
If we fit the camera with a lens with a focal length about 70% of this value or shorter, the angle of view encscoped is said to be wide-angle. If we fit the camera with a lens that is twice normal (200%) the view delivered will be magnified and termed telephoto. If the lens is 7 times longer than “normal” the resulting image will be equivalent to the view as seen using 7X (7 power) binoculars.
Telephoto lenses thus are 2x longer than “normal” or more. It is a simple matter for a lens maker to make these long lenses. Note the use of the expression “long lens”. This is that they truly are. However a long lens is awkward to use, so lens makers strive to make them shorter while delivering the same view (magnification). This is accomplished by fitting the lens barrel with multiple lens elements. Now good lenses must be made this way, as this is how lens errors (aberrations) are mitigated. However to truly earn the name “telephoto” the barrel is artificially shortened by a clever arrangement of lens elements. What happens is the point we measure the focal length from is shifted forward. This point can even fall in the air ahead of the lens. The result is a lens artificially shorter that delivers a magnified view. We call this a “telephoto” lens.
Both a long lens and a telephoto can be fixed as to its focal length. It once was common for photographers to carry a gadget bag filled with an assortment of lenses of different focal lengths. In modern times, we saw the introduction of zoom lenses first fitted to movie and TV cameras. These allow the photographer to adjust the focal length (magnification) allowing the camera to zoom in or out. These soon found their way into the realm of the still camera.
Every lens has many defects we call aberrations. We can mitigate but not eliminate. A typical camera lens is optimized to take pictures of distant subjects. When tasked to take super close-up pictures, it is compromised. A different design called a “marco” is optimized for close-up work and compromised when tasked to image distant subjects.
The bottom line is: Lenses are tools. Some do general work, some telephoto, some wide-angle. Some are Swiss Army Knives that do it all. However, lenses are generally optimized for one task and compromised when asked to do other jobs.
While not exhaustive, these are the terms for lens types I've run into:
A prime lens is a lens with a fixed focal length. A zoom lens is a lens with a variable focal length. Simple as that.
These designations are about the focal length that the lens has: short, medium, and long, respectively. In full-frame equivalency, wide = 24-35, normal is 50mm, and telephoto is >85mm.
Wide angle lenses will generally give a wider field of view and are often suitable for landscape photography. Normal lenses give pretty much the same magnification as your eyes do, unaided, and feel "neutral" as lenses. Telephoto lenses have "reach" and magnify objects, and are often suitable for wildlife and sports.
These terms indicate the maximum aperture of the lens--how wide the aperture can be opened up. The bigger the opening, the faster the shutter speed you can use with the lens, hence the term. Generally, f/2.8 and wider (smaller f-number) lenses are considered fast; f/4 is medium; and f/5.6 and smaller lenses are slow.
Typically means they're past the "typical" ranges. I.e., a "superzoom" lens has a very wide zoom range (typically 10x or more), a supertelephoto is typically a lens with a focal length of 400mm or longer. An ultrawide lens is one that goes wider than a typical wide angle lens.
A walkaround lens is a lens that's good for casual shooting while walking around. It's most typically going to be a wide-to-slightly telephoto zoom, such as an 18-55 kit lens for crop. But can also be a fast wide/normal prime or a superzoom, depending on the shooter's preference.
A portrait lens is (obviously) a lens for taking portraits. It is typically considered to be a fast, slightly telephoto prime, but can also encompass f/2.8 telephoto zoom lenses, or a fast 35mm lens. It all depends on the shooter's preferences.
The more exotic lenses also have specific terms to differentiate them.
Macro: Lenses specifically designed for close-up photography, they typically use a floating element or group to optimize the minimum focus distance. Very sharp lenses for the most part.
Fisheye: Lenses that do not map straight lines as straight (rectilinear), but as curves to cover a much wider field of view. Tons of distortion. Comes in two flavors: diagonal (which cover the sensor corner-to-corner) and circular (which puts the entire image circle into the frame, so yields a circular image).
Tilt-Shift: Lenses that can be shifted from the center of the camera mount to the top/bottom/left/side and that can also tilt relatively to the front face of the camera to approximate view camera movements. Used for perspective correction, viewpoint shifting, toy/model effect. Always manual focus lenses.
Mirror: Mirror lenses use a mirror instead of glass elements to achieve large magnification, typically at low cost. Very slow, often fixed aperture, and (if inexpensive) can be very soft.
Manual: Manual lenses do not communicate electronically with the camera body. Sometimes they're vintage lenses, but they can also be new lenses, such as those from Samyang. As a result, they do not autofocus, aperture must be set with a ring on the lens, there is no lens EXIF information, and stop-down metering must be used.
