Photography News issue 17

Technique PHOTO SCHOOL

Everyone has to start somewhere, even pros, and here we look at the core skills everyone needs. This month, how to use spot metering and how to recover detail in Lightroom Camera class

Words & pictures by Kingsley Singleton

n What is spot metering? Your camera bases its exposure on the metering mode that’s set by you, and for the latter you can broadly choose from three – multi-zone, centre- weighted and spot. Each of these averages out all the lights and darks it can see into a mid-tone value on which it bases the exposure settings. Multi-zone (called different names by different manufacturers, like Evaluative [Canon], Matrix [Nikon] or ESP [Olympus]) and centre-weighted both use the whole frame but bias the reading towards the point you’ve focused, or the middle, respectively. Spot metering uses only a very small area of the frame to judge the exposure, often less than 5% and this is very useful if your subject demands highly accurate metering or if you want to achieve creative effects, like silhouettes. Some cameras also use partial metering which is like spot, but a little broader. n How to set spot metering mode In program, aperture- or shutter-priority mode, switch to spot metering (its icon is a dot inside a square). This can be done using a dial on the body or via the metering/photometry settings in the menu. Now, whether you’re composing via the viewfinder or the camera’s screen, the part of the

frame used to spot meter is usually allied to the active AF point, or the centre of the frame. Move this over light and dark parts of the scene and you’ll see the exposure settings vary much more widely than if you were using other modes. n Spot metering in action Depending on whether you spot meter on a light, mid-tone or dark area (or anywhere in between), you’ll get a very different reading, because of the increased accuracy. Taking the example on the right for instance, spot metering on the light background turns the subject into a silhouette, because the camera thinks this is a mid-tone. Spot metering on the window frame gives a ‘normal’ exposure, because it’s close to a natural mid-tone itself. Spot metering on the subject itself gives a balanced exposure. n Spot and go Much likewhen locking the focus and recomposing, when you move the camera the spot metering will fall on a new area and take a new reading. To lock the exposure settings you’ll need to press and/ or hold the A-EL (exposure lock) button on the camera, shown as a * on Canon DSLRs. With this held you can recompose with the settings locked.

ABOVE Because spot metering is so accurate, wherever you take the reading in the scene you’ll get very different results: here, the bright background gives an exposure of 1/500sec at f/2.8; metering from the window frame gives 1/125sec at f/2.8 and metering from the shadows on the subject gives 1/30sec at f/2.8.

NEXTMONTH: More great exposure and Lightroomprocessing tips for photographers.

Software skills Part 17: Controlling highlights & shadows ADOBE LIGHTROOM

STEP 1: SET UP THE CLIPPING Opening your picture into the Develop module, go to View>Show Clipping (or as a shortcut, hit J on the keyboard, or click the triangle icons at either end of the Histogram). You’ll now see underexposed parts highlighted in blue, while overexposed areas are shown in red. If you move the Exposure slider left or right, you’ll decrease the clipping in one area, but increase it in the other, so you need to do something different. The Highlights, Shadows, Whites and Blacks sliders are what’s needed here, as they let you control some parts of the picture without affecting the others too much. STEP 2: RETURN THE DETAIL The sliders are set out in this order as that’s the best way to use them. First move the Highlights slider left until the red clipping has gone, then move the Shadows slider right until the blue clipping disappears, too. If you can’t fully remove the clipping, return to Exposure and move that to brighten or darken the pic overall, then try again. You’ll now have returned detail to the whole pic, but to make sure it has a ‘true’ black and a ‘true’ white point, move the Whites slider right and Blacks slider left until the warnings return in tiny areas to show black and white pixels are there.

AFTER

BEFORE

In many scenes, the intensity of the light varies too widely for your camera to correctly expose everything, and parts will become over- or underexposed. What you’re left with is areas of pure black or pure white (or close to it), and these blocked-out parts of the pic contain no detail. In some shots, this doesn’t matter, but if you want to avoid the problem, shoot in Rawmode and process your pics in software like Lightroom. In this example picture we’ve actually lost detail in both the highlights and the shadows, but using the clipping warnings and the sliders in Lightroom’s Basic tab, it can all be sorted.

Photography News | Issue 17