12 Learn How To Photograph Flowers In the Wild Get the photo that you always dreamed of getting! Pages The definitive guide to SLR photography Take better Nighttime Shots Get to know your camera lenses betterDigital Camera Magazine 1 focal length, aperture, stabilization, and more! CONTENTS features Camera Lenses Explained........................................ 2 Child portraits: studio at home................................ 5 How to Photograph Flowers In The Wild................. 8 How to photograph the Northern Lights.................11 The hardest photography quiz ever....................... 12 Digital Camera Magazine 1 Camera Lenses Explained A lens focuses light onto the sensor of a digital camera and is critical to photography. lens focuses light onto the sensor of a digital camera and is critical to photography. To help you make an informed choice when buying or mounting an optic, we explain some of the most important features of Alenses. Focal length is the distance in millimetres from the imaging surfwace (film or sensor) and the optical cen- tre of the lens when it is focused at infinity. As lenses are made up of multiple elements arranged in groups it isn’t always immediately apparent where the optical centre is, but, with a few exceptions, longer focal length optics are usually longer than shorter ones. With full-frame cameras – those that have a sensor that is the same size as a 35mm film frame – lenses longer than 50mm are considered telephoto optics because they have an angle of view that is smaller than our eyes. This means that a distant object will appear larger in the frame than we see it and we often refer to telephoto lenses as getting you ‘close’ to the subject. Lenses with a focal length shorter than 50mm are generally regarded as wide-angle optics because they have a wider angle of view than our eyes. As you’ve probably already deduced, 50mm lenses have an angle of view that is roughly the same as our eyes. But what is angle of view? Imagine drawing two lines from a lens’s optical centre to the outer opposite edges of the scene visible through the lens, the angle between these lines is the angle of view. Angle of view can be measured vertically, horizontally or diagonally (this gives an increasing measurement in landscape orienta- tion). Canon’s 50mm f/1.8 lens, for example, has an angle of view of 27, 40 and 46 degrees (vertical, horizontal and diagonal). Meanwhile the angle of view of the Canon 100mm f/2 is 14, 20 and 24 degrees. These figures can usually be found in a lens’ specification list to indicate how much of a scene is visible through it. 2 Digital Camera Magazine Prime lenses are lenses that have a fixed focal length, whereas Camera Lenses Explained zoom lenses allow you to change between focal lengths without changing lens. Zoom lenses are extremely convenient and their quality has improved enormously over the years, but they still have to make some compromises in order to enable the focal length shift. This means that a series of comparable prime lenses will usually produce better quality images than a zoom lens. Broadly speaking, the wider the zoom range, the greater the degree of compromise that has to be made. As mentioned earlier, a prime lens’s focal length is fixed. However, if you take a 50mm lens as focal length magnification and Thirds cameras have a mag- and put it on an APS-C format cam- cameras with smaller than full- nification factor of 2, so a 50mm era you will see less of a scene frame sensors are said to have a lens produces images that look like than you will if you put the same focal length magnification factor or those shot using a 100mm lens on optic on a full-frame camera. The crop factor. Canon APS-C format a full-frame camera. A lens aperture smaller sensor size of the APS-C SLRs like the EOS 7D Mark II or is the hole that is used to control format camera fills a smaller part of EOS 700D etc, have a focal length how much light enters the camera. the lens’ imaging circle and effec- magnification factor of 1.6. This This hole is created by a series of tively produces a cropped version means that a 50mm lens will cap- blades inside the lens that make of the full-frame image. As a result ture an image that looks the same up an iris that can move to open or it makes the lens appear to have a as one captured by an 80mm (50 close and change the size of the longer focal length than it actually x 1.6) on a full-frame camera.Micro aperture. Aperture value is calcu- has. This effect is often described Four lated using the following formulae: Aperture value = Focal length (f)/ Aperture diameter in mm Even though the aperture diameter of two different lenses maybe different, if the aperture value (or f/number) is the same, they will let the same amount of light through. Lenses are marked with their maximum aperture setting. Short focal length prime lenses typically have maxi- mum apertures of f/1.4, f/1.8 or f/2 while telephoto lens are more likely to have maximum aperture settings of f/2.8, f/4 or even f/5.6. High-end, expensive zoom lenses are able to maintain the same maximum aper- ture setting throughout their focal length range. Less expensive zoom lenses, however, have a variable maximum aperture settings. The kit lenses sold with many DSLRs and compact system cameras often Digital Camera Magazine 3 have a maximum aperture of f/3.5- 5.6. This means that at the widest setting the aperture can be opened up as far as f/3.5, while at the lon- gest telephoto point the maximum aperture is f/5.6. If you set the lens to f/3.5 at the widest point and zoom in, the aperture changes to f/5.6 by the time you reach the lon- gest point. Long lenses with a maximum aperture of f/2.8 or greater and shorter lenses with apertures of f/2 or f/1.8 are often referred to as ‘fast’ lenses. This is because they allow more light through than their slower counterparts with smaller maxi- mum apertures, and this enables faster shutter speeds to be used. Fast telephoto lenses are there- fore very popular with professional sports photographers because the long focal length allows tight fram- ing of the distant subject while the wide maximum aperture enables movement-freezing shutter speeds to be used. Some lenses have an element inside them that can move to compensate for those accidental movements that are made when we hand-hold a camera. In some cases this stabilisation system has several settings; there maybe one that restricts the correction to verti- cal movements, for example, which is useful when panning to follow a moving subject. Some image stabilisation sys- tems can also be set to only acti- vate when the shutter release is fully depressed to take a shot. This means that the view through the viewfinder isn’t stabilised as it would be normally, but the range of correction available at the time of capture is greater, potentially mak- ing it more effective. Some longer lenses have focus limiting switches which are designed to cut down on the time that a lens takes to focus on a subject when it is within a particular distance range from the camera. This also cuts down on any distractions for the AF system, 4 Digital Camera Magazine making it more accurate. In some cases it is even possible to custom- ise the focus range for a lens. This is especially helpful when there are likely to be objects between you and the subject as the camera will ignore them and only focus within the range specified. Oreces endus et, odipsame istio. Nequi conse rem. At magni officti orrovid quid evelest eceptat eos perferu mquam, aut idelitaqui aperiatur acerumque sumquis sum aut doluptat quam es dolorit magni- tium quis explia vellandione perum ipsam etur? Qui commossi alit pel iumquas aut vid millumque officil intium et mo vel id eaqui offic to imolum qui comnim iusam, acest omni aut utaquia vendignat. Ur? Harciam, ute ea volut mo ex etur? Quia nimpos venisci aero- vit quo in pore ipsamusam andici te est optaquae. Perunti accus.Ximus in nis ipsanis es nam si aut as duci officiae moloribus sus.Uptas dolore vendaepre, qui rectatiusdae exceper sperfera doluptati consern amusdae comnis eicat quae es nonet asitati dolore velent. Rerum adicidel essi quatem hario dis aute nem qui dita vid mag- nis eseroviduci quidenis sunt asse- quas a dollut quo vella voluptam fugit exceptatem dolorio moditatur magnimi, omnist ommolum fugia nossunt est volor mil illes sum rem- porum hariore quo deliquati volupta tatur, sed minum cone voluptasit ut adi de omnis aliquat etur rempori amenda idi consectem cus undit eum alias et aliquam everrovid maximus cillaci lliquo tem. Excest estis essitatum nonet aut aut eve- lest arum ipsam alibus rem utVid quis voloruptatem ium soluptas modis simil event dolut adio te rem ullabore cusa conet optur mi, quunt ut eumeni ommo ex eum qui in nos ad quia dit que elest faciamene omnima volor autas experch illique Digital Camera Magazine 5 0ompared the to other aspects of nature photogra- phy, shooting wild plants and flow- cers is a stroll in the park. After all, they can’t run off and you don’t need to lug back-breaking lumps of glass around with you to get a decent shot.