Photography News 02

Technique PHOTO SCHOOL

25

Camera class

APERTURESCALE

F/ 1.4 1.6 1.8 2 2.2 2.5 2.8 3.2 4 4.5 5 5.6 6.3 7.1 8 9 10 11 13 14 16 18 20 22

Everyone has to start somewhere, even top pros, and in our regular Photo School feature we’ll be taking a close look at core techniques that every beginner needs to know. This month, in Camera Class we look at apertures and f/numbers, while Software skills (below) looks at cataloguing images in Adobe Lightroom

Words by Ian Fyfe

The aperture is an adjustable ‘hole’ or iris that lets light through the lens to the camera’s sensor and, together with the shutter speed, creates the exposure. The size of the aperture is denoted as an f/number and you see this in most camera viewfinders and on the rear monitor. The f/number is one of the most important settings on your camera and you should keep an eye on which value you are using. n  How does changing the f/number affect the aperture size? One of the most confusing things about the f/number and aperture is that smaller f/numbers indicate larger apertures and vice versa. See the illustrations far right. n  Where do the f/numbers come from? The available f/numbers form a standard scale, with each value referred to as an f/stop. At first, the f/numbers seem like a random sequence of numbers, but the scale has a mathematical basis. Each full f/stop lets in half as much light as the one above, and twice as much as the one below. Thus f/8 lets in twice as much light as f/11 but only half the light of f/5.6 – the bigger the ‘hole’, the greater the amount of light is allowed to pass. n What does this mean for my exposures? An exposure is basically a balancing act between aperture (the amount of light coming through Software skills Take control of Adobe Lightroom. Part 2: Cataloguing adobe Lightroom Adobe Photoshop Lightroom is one of the most widely used cataloguing and editing softwares available. The full version 5 costs around £90, but you can download a 30-day free trial from the Adobe website. Other options include Corel AfterShot Pro and Cyberlink Photo Director 5. In part 1, we looked at importing images to Lightroom 5 and in part 2, this month, it’s onto using the catalogue features. Words by Will Cheung

right When you look through your camera’s viewfinder, this is the kind of thing you’ll see. The selected aperture or f/stop is displayed here in yellow. far Right This is a typical aperture scale. The numbers in yellow are the traditional full f/stop values and those in between are 1/3 f/stop increments.

the lens aperture) and shutter speed (the amount of time the sensor is allowed to receive the light coming through the lens aperture). The bigger the iris, the greater the amount of light coming through the lens, and that allows a shorter or faster shutter speed. If the iris is set to a higher value, thus giving a smaller ‘hole’, a longer shutter speed is needed to compensate for the lower level of light coming through the lens. n What about the f/numbers in between? On lenses for old cameras, the aperture control was less advanced and only full f/stop values were possible, ie. f/4, f/5.6, f/8 etc. On your modern camera, you

can set the f/number to values in between these full f/stops, for example f/6.3. These are partial f/stops that divide each full stop into thirds, and they simply have one third of the effect. Some cameras also allow half f/stop settings. n  What other effects does changing the f/number have? Opening and closing the aperture not only changes the amount of light that passes through, but it affects something called depth-of- field – the amount of back-to-front sharpness in a scene. Controlling the f/number can therefore be used for creative effects, and we’ll look at depth-of- field in more detail next issue.

Get to grips with depth- of-field for creative effects and start building Lightroom collections. NEXTMONTH: DEPTH-OF- FIELD& COLLECTIONS

Rate them Click on Photo in the menu tool bar and you will find options of Set Flag, Set Color Label or Set Rating. Quick keys speed up the process, ie. hit 5 to give an image five stars or 6 to label it red. How you use these labels is up to you but five stars for definite keepers and three for a maybe is a good start. Later you can turn on filters and view all your five star pictures or all those labelled red, for example. Lookingat your shots Turn the filters on (Ctrl+L or Cmd+L) by clicking on the words: Filters Off, either top right of the Library module or in the bottom right corner, choosing the filtering method you want, say Rated. You can then refine this further by clicking on the flag, colour patch or stars in the bar that appears. Reject the rubbish Now’s also the time to delete the rejects (don’t delete in camera). Do that by hitting X and then later go to Photo>Delete Rejected Photos if you want the software to bin the images completely. You can also just delete the image from the catalogue but retain it on your drive.

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