Basic understanding of DSLR  lenses

Basic understanding of DSLR lenses

If you are a beginner and  plan on buying a DSLR, or already own a DSLR but not sure about lenses, and if you are  having problems  understanding different  types of lenses, what to buy or what is kit lens/ wide angle/ telephoto or prime lens then we hope that this post will help you. Honestly,  even I was very confused when I had planned to buy a DSLR and as a beginner I was skeptical about which lens to go with.Each lens and focal length have different photographic purposes. Sometimes you need to get close to a subject without disturbing it.

baisc undersanding of dslr lens

what sets the lens apart?

What sets each  lens apart is its large aperture. An aperture is the opening that lets light enter the camera, and the amount of light that enters is measured by f-stops. A wider aperture means more light comes in, and you have a better chance of getting nice shots indoors, or in dimmer settings. A narrower aperture lets in less light. The trade-off is that a wide aperture can’t focus on many things that are at different distances—it is said to have a “shallow depth of field” where your main subject is clear, but the background is blurry—artistic in many cases but can get annoying in some cases. When you narrow the aperture, you can crisply resolve more elements, but only if there’s enough light. The wide aperture of a “fast” lens can always be narrowed, but there is no way for a “slow” lens with a narrower aperture to bring in more light.

F-stops are used for controlling light exposure and is determined by focal lengths. If the f-stop is low (f/3.5) the aperture is wide and more light goes in , and if it’s high (f/7.1) the aperture is narrow and less light goes in. This idea is hard for some users to grasp but its quite simple once you get the idea. you can also read an earlier post 5 things to better understand depth of field to understand aperture and Dof better

Kit lens

It doesn’t matter what brand camera you buy—if it’s an entry-level DSLR, it is offered with a 18-55mm kit lens. Like most bundle pricing, it’s cheaper than buying the camera body and lens separately. As most experts agree, I myself assert that a 18-55mm is actually the perfect lens for most immediate photographic needs, because it includes both decent wide angle plus the ability to zoom in on objects that are far away.


nikon kit lens 18-55

Telephoto lens


Also termed as tele lens , a telephoto lens helps  zoom farther object/subject. It takes light directly from the subject whereas wide lens takes light from both subject and its side. So technically zoom lens need more  light than the wide lens. There are zoom lenses which allows you to open the aperture wider but the trade off would be extra expense. If you have used binoculars before,  you may to some extent relate to telephoto lens as it helps you to view the subject or scene at the greater distance and makes it appear close. You may get two types of tele photo lenses in the market,  one which will allow you to zoom but you does not allow  you to open aperture wider than f 5.6 , the second type allows you to open your aperture much wider. The lens which enables you to open aperture wider would be much more expensive than the regular lens,  but will help you to take much faster images and works miracle even in  low light setting.

Wide Angle and Telephoto Focal Length

A very good question to consider would be what is the right lens for you,  but this question would make more sense with the given scenario. Though different, both these lenses have equivalent importance at a given time and setting. For example in a scene where you have to capture a subject without disturbing anything, let’s say wildlife photography , in such a case a zoom lens would work the best while the other lens would not serve any purpose here.  Another example is where you have to capture a scene, for instance a landscape,  than a wide lens would be the right choice, a zoom lens would not be very helpful in capturing the beauty of a landscape. So you can see how both these lenses equally play a crucial role in capturing your subject.

Prime Lens

35 mm nikon prime lens

Prime lens would be a lens where focal length is fixed, meaning you cannot  zoom in or zoom out. If you buy a 35 mm fixed lens all you get is a lens with fixed focal length of  35 mm, however do not underestimate the power of prime lens just because you do not have the option of changing focal length. Prime lenses are one of the most preferred lens in photography world.

Why consider fixed lens?
If your lens has only fixed focal length and does not let you change focal length, neither zoom or zoom out, why even consider buying fixed (eg 85 mm) when when you can buy a telephoto lens (50-200mm) making the financial option secondary. Mentioned below are few reasons as to why fixed lens are recommended:

1. Get the best quality photographs

If you measure quality of pictures with its sharpness , distortion , vignetting ,and chromatic aberration you will most probably fall in love with the prime lens. With best sharpness and least distortion, vignetting and chromatic aberration, fixed lens ranks the best when it comes to quality of images.

2. Wider aperture at low cost

Fixed lens gives you wide range of  apertures at much lower cost in comparison to telephoto lens.  When you add wide aperture to a zoom lens its expense becomes higher since much bigger lens is required.

Previous 5 things to better understand depth of field.
Next Raw vs Jpeg make a better choice

About author

Anup Ghimire
Anup Ghimire 60 posts

Anup ghimire is a self learned Photographer/Designer and recently graduated in multimedia technologies from London metropolitan university.Traveling is something he loves the most after photography. You can see some of his photos at his facebook photography page

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