photography tutorial: how to choose your camera lens

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How to Choose Your Camera Lens http://www.photographytuts.com

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How to Choose Your Camera Lens

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Free ebook by

Photographytuts.com

This free ebook is part of Photographytuts.com eBooks series. Click here to join our newsletters and get more free tips and ebooks.

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Copyright © 2013 by Photographytuts.com

All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law. For permission requests, write to the publisher, addressed “Attention: Permissions Coordinator,” at the Email address [email protected]

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Table of Content Introduction 5

Build-quality 5

Lens Coating 6

Auto-focusing Sound 7

Image Stabilization 8

Prime Vs. Zoom 8

Aperture 9

Manual Focusing Override 12

Lens Format 12

The Ubiquitous Kit Lens 12

The Need for Telephoto Lenses 12

The Wide Angle Perspective 15

Getting Up Close and Personal: The Macro Lens 16

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The decision to choose your first lens can be a tough one to make. In a world of jargons buying a decent piece of glass that can get you those perfect pictures with well saturated colors can be a daunting task no matter how much time to you spend deciding. Not knowing what you might end up with, especially when you don’t have an unlimited budget, can make the whole decision making process a stressful affair. This tutorial is aimed at making the decision as smooth as possible, so that you end up making an informed decision and ensure that you buy a lens that is perfect for your needs and within your budget.

Build-quality Build quality is an important factor for both professional photographers and amateurs alike, more so because of the growing incidence of photography pursuits that are bordering on the edge where man and equipment breaks down. When facing the elements, both needs to be in top shape, and to ensure that it is imperative that the lens has some sort of weather sealing and is capable of handling the odd bumps and knocks. In an urge to shoot professional quality photos, in the most demanding of circumstances, photographers are looking for not only the best optical quality but also the best build quality. If you're looking for something that can handle splashes, hail, snow, dust, dirt and a bit of knock here and there, look for options that come with weather sealing and have a sturdy construction. These lenses are moderately to very expensive but are worth their price tag in terms of the advantage they provide. Canon’s L series lenses or Pentax’s weather sealed lenses are great choice for a quality glass. Apart from the lenses, your DSLR body should also have weather sealing and higher end professional and semi-professional DSLR models come with this feature. Pentax has a series of cameras that

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come with weather sealed bodies, which are extremely well built. A number of their DSLR bodies have stainless steel chassis plus magnesium alloy outer shell covers.

If the most adventurous that you would ever get with your camera is shooting on a weekend trip and that too only after taking a rain check, then save the extra amount of money and buy something that is less demanding on your forearms. If you have a Canon DSLR body then many of the G series (minus the aperture ring) lenses would be ideally suitable as these are mostly plastic made, are lightweight and cheaper.

Lens Coating Lens coating is often an underappreciated addendum for lenses, the reason being average amateur photographers don’t quite understand what they do. Pentax’s Super Protect (SP) coating e.g., is used in some of its higher end lenses to prevent dirt, dust, grease and fingerprints from affecting the front elements. Lenses, which have SP coating, can be easily cleaned when these greasy substances smear the front element compared to traditional lenses without Super Protect (SP) coating.

Pentax 90mm Macro lens

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Ghosting and flares are the result of light that is reflected off the lens back element, which then again gets reflected off the surface of the lens and creates a faint secondary image. Surface reflection of light reduces the quantity of light reaching the sensor and creates a less than sharp image. Different manufacturers use different types of coating technology that reduces surface reflections.

Nikon SLR Nikkor Lenses

Nikkor lenses come with a special Super Integrated Coating (SIC). It is used specifically to counter the problem of ghosts and flares. Nikon also uses another type of coating known as Nano Crystal Coating, to counter this problem. Nano Crystal Coating is mostly used in lenses which have a shorter focal length (wide angle) specifically to counter ghosting and flares, which are typical to these lenses.

Auto-focusing Sound Auto-focusing sound may not be a problem when you're shooting in a crowded place. But when you're shooting street photographs or trying to photograph a fidgety bird perched on a branch it makes ample sense to have a lens that does not screech when auto-focusing. Nikon’s AF-S lenses powered by SWM (Silent Wave Motor) for example, is a great piece of technology that offers super quiet auto-focusing.

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Image Stabilization Image stabilization is important, if you're going to shoot mostly hand-held and or when shooting in low light conditions. Image stabilization compensates for the lateral or vertical movement of your hands when shooting at very slow shutter speeds. In fact it gives you the luxury to shoot at one, two, three or even four stops of slower shutter speed than you would normally be able to when hand- holding the camera. Image stabilization is extremely important when it comes to choosing a telephoto lens. This is because at extremely long focal lengths even the slightest of hand movement is magnified, ruining the picture. Modern auto-focusing lenses come with lens based image stabilization system that works by re-aligning the image on to the sensor surface when there is a shake of the hand. Major brands such as Nikon and Canon comes with lens based image stabilization systems If you're looking for a body based image stabilization system, one that can stabilize all lenses, which are designed for that particular system then you could opt for one of Pentax’s DSLRs which have in body image stabilization system. You can also check How Does Your Camera Image Stabilizer Work? to learn more about image stabilization

Prime vs. Zoom Prime lenses have a fixed focal length (e.g. 50mm) whereas zoom lenses have a variable focal length usually expressed as a range (e.g. 18-55mm). There are advantages and disadvantages of both prime and zoom lenses.

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Most photographers would buy around 2-3 lenses over their life and at least one of them would be a prime lens. Prime lenses have less moving parts inside, the reason being they have only one focal length. This is a considerable advantage for lens makers as they can concentrate their energy and strive for a better optically superior lens. Prime lenses for this reason are also lighter compared to zoom lenses. Prime lenses also tend to have wider apertures for this reason.

Nikon lens with 50mm fixed focal length

If you need a lens that can shoot anything from a wide-angle shot of a landscape to wildlife then opt for something like an 18-200mm lens. If you would be predominantly shooting portraiture then a 24-70mm lens is ideally suitable for you. Similarly for street photographers a 50mm prime is a great lens to have.

Aperture Aperture is small opening at the front element of the barrel that controls the amount of light that enters the lens and reaches the image plane. Smaller the aperture less is the quantity of light that reaches the sensor or film and vice versa. Aperture sizes are expressed as F-stops and written such as f/1.4, f/1.8, f/2, f/2.8 and so on. Every consecutive f-stop

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(bigger f-number) makes the aperture smaller and practically halves the quantity of light that passes through. Both big (smaller f-numbers) and small (bigger f-number) apertures have their advantages and disadvantages.

There is an inverse relationship between aperture and shutter speed. Bigger apertures allow more light in, which as a result require very small amount of time to make the exposure. Thus when bigger apertures are used one can use faster shutter speed (thus the name fast aperture. Also bigger apertures create a soft out of focus effect for backgrounds, which are very useful when shooting portraits. Bigger apertures are also ideally suitable when shooting images in low light conditions as they can capture a lot of light for a given shutter speed.

The aperture in Canon 50mm lens

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On the other hand smaller apertures are suitable when one needs to make almost the entire frame to be acceptably sharp. However smaller apertures needs a longer shutter speed to make a proper exposure. It also creates a higher chance of image shake. You can read Understanding Camera Exposure to learn more about digital camera exposure and how it is affected with the aperture value.

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Manual Focusing Override This is somewhat of a specific requirement for those who want smooth auto to manual focusing transition without having to constantly flick the A/M switch. When this mode is selected one can use the normal auto-focusing option and then turn the focusing ring manually to precisely lock focus even while auto- focusing is engaged. In real world situations this saves a considerable amount of time not having to flick a switch and then turn the focusing ring. That fraction of a second saved can make a lot of difference.

Lens Format Lenses are designed in two main categories, for full frame DSLRs and for APS-C (crop bodies). Lenses designed for full frame bodies make full use of the larger sensor. When used on a smaller APS-C sensor based bodies only the center part of the image circle is used, evidently converting the lens a slightly longer focal length. This is also known as crop-factor. You choice of a lens format would depend on the type of camera body you have. It does not make sense to buy a APS-C format lens if you're using a full frame DSLR as it will never be using the capabilities of the large sensor fully. On the other hand if you have both a full frame and a crop body you're likely able to use the full frame lenses on your crop body.

The Ubiquitous Kit Lens The first lens that a majority of DSLR / ILC users end up buying is the kit lens. Most entry level DSLRs (based on a cropped APS-C sensor) come with the standard 18-55mm lens which effectively becomes 27-87.5mm on the 35mm format. These lenses are great for general-purpose photography and offer a great deal of value for money.

The Need for Telephoto Lenses Standard zoom lenses or prime lenses less than 100mm are not suitable for the purpose of photographing birds, wildlife or even sports from a distance. When shooting wildlife for example you cannot hope to get up

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close without perturbing them. Additionally when covering sports you need to stay at a safe distance away from the action and yet get up close with your lens’ built-in reach to get super sharp pictures of the action going on in the middle. The solution in these cases is to use a longer than usual focal length lens such as a 200mm, a 300mm or even a 500mm telephoto lens. Telephoto lenses have a narrower Field of View and are perfect for the purpose of ‘filling the frame’ with a subject that is far away.

Sigma 120-300 mm telephoto lens

Telephoto lenses also have an interesting effect on the Depth of Field of your images. Invariably the Depth of Field of your images will be shallow. When choosing a telephoto lens insist on something that has a slightly brighter max aperture. High end lenses from both Canon and Nikon comes with a fast and constant max aperture of f/4 and even f.2.8 for their telephoto range of lenses. It helps to create a sharp well-contrasted image even from a considerable distance. Wider apertures also help in using a faster shutter speed. Faster speed is imperative when you're shooting wildlife or sports. Another requirement for telephoto lenses is image stabilization. Image stabilization can come in two different forms – (a) which is lens based (b) which is body based. Camera systems such as Pentax come with body based Optical Image Stabilization systems. These are basically sensor-

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shift type based. On the other hand Canon and Nikon, for example manufacture systems that have lens based image stabilization systems. There are pros and cons for both (as manufacturers would want us to believe). Lens based optical image stabilization ensures that the stabilization system has been specially designed and optimized for that particular lens. On the other hand when body based optical image stabilization is used all lenses which are compatible to that line of camera enjoy the stabilization feature.

Different telephoto lens

Telephoto lenses are used mainly outdoors where the elements of nature such as inclement weather, dirt and dust can damage them. It is imperative that you select a lens that comes with some kind of weather resistance properties if you're going to shoot images out in the open. Canon’s L series lenses come weather sealing and so does Pentax’s advanced lenses. It has to be kept in mind that using only weather sealed lens where the camera body itself is susceptible to weather conditions doesn’t make much sense. It is thus imperative that along with the lens the camera body also should be weather sealed.

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The Wide Angle Perspective For shooting landscapes, architecture, group photos or wedding you need a lens that has shorter focal length giving you a wider than normal perspective. Standard lenses are limited in terms of their angle of view and telephoto lenses are absolutely unsuitable for that very reason. Wide-angle lenses have a big diagonal angle of view, which makes it possible to capture a lot of the scene without having to back out a zillion miles. Wide angle lenses also have a very short hyper focal distance which is perfect for the purpose of keeping much of the frame in sharp focus, a must have requirement for landscape photography.

Canon 17-40mm wide-angle lens

Another advantage of wide-angle lenses, especially those which are of prime lenses are the wide maximum aperture that they in. It is great to have such exotic max apertures as f/1.4 as it allows you to use the maximum shutter speed allowable by your camera mechanism in order to freeze the action. When shooting in low light conditions you can use the big aperture to good effect by collecting more light and creating a properly exposed photograph.

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When choosing lenses care should be taken that they come with the necessary coating to ensure that ghosts and flares are corrected / suppressed. We have already discussed about lens coating elsewhere on this document in some detail.

Getting up close and personal: The macro lens Macro lenses offer a very close focusing distance. These lenses allow a photographer to fill the frame with even the smallest of subjects. Ideally a true macro lens is one that offers 1:1 magnification that means representing a subject life size on the sensor. There are a zillion number of lenses available which come with the term ‘Macro’ on them but don’t offer 1:1 or life size reproduction. Avoid them as they are not true macro lenses at all and could only end up giving 1:2 or even 1:4 magnification.

Canon 100mm macro lens

Macro lenses are prime lenses that mean they come with a fixed focal length. There are different macro lenses available in the market but the most common ones are those, which come with a focal length of 50mm to100mm. There are also some, which are even higher than this. More the

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focal length, the more is the distance from which you can shoot your pictures and get away with stunning captures. The best thing about these lenses is that they can also be used for ‘normal’ photography. That means your 100m-macro lens can easily double as a standard portrait lens. Image stabilization is an important requirement when selecting a macro lens. Although the best of macro photography enthusiasts would only even use a macro lens with a tripod, there may be need to shoot hand-holding. In such conditions optical image stabilization is an absolute must to have. Learn more about macro photography through Beginners’ Guide for Macro Photography. There are many other special purpose lenses, such as Tilt-shift and Fish-eye etc. These lenses are used for specialized requirements by professionals to get a unique perspective.

photography tutorial: how to choose your camera lens

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