Photography News Issue 43

Photography News | Issue 43 | absolutephoto.com

Technique 33

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What to look for in a standard prime

Front element The front element is the business

Lens hood A lens hood helps cut out lens

Maximumaperture This states howwide the

Focal length A standard focal length is around 40mm or 50mm on a full-frame camera. If you’re using one with a smaller sensor, like an APS-C chip, it will be closer to 30mm or 35mm. Prime lenses only have one focal length, so you’ll need to move your feet instead of zooming when you want to recompose. 7

Lensmount The mounting point between

end of the lens, so it needs to be kept clean and well protected. Many lenses have water and oil-repellent coatings nowadays, which can make cleaning them easier. Or fit a protection filter.

flare, which is caused by bright light sources striking the front element. Flare, in the right situations, can be attractive, but it also lowers contrast and leaves artefacts on the image. A lens hood also protects the front element from knocks.

aperture will open; on standard primes you can look forward to fast apertures like f/1.4 or f/1.8. The wider the aperture the easier it will be to exposing and focus in low-light, and to blur parts of the scene.

lens and camera. Of course, it needs to be one that fits your camera make, and a metal lens mount will offer greater strength and durability in the long term. Some lenses have weather sealing here, too, protecting the camera and the lens contacts.

Filter thread Filter (sometimes called

Focus distancewindow This shows where the lens is

Focus ring The focus ring is used to

Controls Switches here will include

accessory) thread size varies from model to model, and you’ll need to know this to fit screw-on filters or a filter holder, which will help control the light or protect the front element from scratches. You’ll often need an ND filter to shoot at very wide apertures. Bigger sizes mean more expensive filters. How fast a maximum aperture you need depends on what kind of light you’ll be working in. The wider the maximum aperture the more light you’ll be able to record, so faster shutter speeds can be used, which is especially helpful shooting hand held in low light. Wider apertures also give shallower depth-of-field. Size and weight Again there’s lots of variation out there. As a rule of thumb, the wider the maximum aperture of the lens, the larger and heavier it’s likely to be, as more glass is used to keep image quality high. But heaviness in itself isn’t an issue if you’re used to heftier cameras and lenses. Themost important thing is to consider how you’ll be using the lens, and for how long. While its quality will likely be greater, a heavy lens can weigh you down and spoil your enjoyment after a white, and large lenses can attract unwanted attention. So, in some instances smaller and lighter is the way to go, even if it means missing out on performance. Build and handling Getting a lens with good quality build means it should be able to take the odd knock, so look for use of metal and high-impact plastic on the barrel, as well as a solid feel without any rattling or a hollow feel. The focusing ring should bewell grooved

focused between infinity and the lens’s closest focusing distance, measured in metres and feet. Some lenses also have a depth-of-field scale, so you can quickly tell what’s in focus and what isn’t.

manually focus the lens, and also, in the certain AF modes and some systems, to make minor corrections after the autofocus has kicked in.

features like switching from auto (AF) to manual focus (MF). There’s unlikely to be much else on a standard lens, as image stabilisation and focus limiting don’t tend to be included.

and smooth in the turn without feeling loose, allowing manual focus to be used with accuracy. If the lens has weather sealing it’s a bonus. Using filters When buying a standard prime, people don’t often think of filter size, but it’s a big factor. If youwant to use the widest apertures in bright light, you’ll need to fit neutral density (ND) filters, and even when you’re not, a protection or UV filtermakes a lot of sense to guard the font element against damage. Check the size to see if you can use filters you already have, or need to invest in new ones. Focusing and image stabilisation They’re not action lenses as such, but the focusing speed and accuracy of standard lenses is important for portraits, street and general shots. And though a lot of the performance comes from the camera’s AF system, the lens’s focusing motor is also important. Examples like Sigma’s Hyper Sonic Motor, speed up focusing and keep it quiet. Standard lenses don’t tend to use image stabilisation, mainly as their very fast maximum apertures mean higher shutter speeds can be used to counter camera shake. Image stabilisation systems also adds size, weight and cost to a lens, so up until now, it’s not something lens makers have seen fit to include.

Primes afford wider maximum apertures than most zooms

Above Standard focal lengths, like 50mm on a full-frame DSLR (right) give the most natural view of the world – compare this to the forced perspective of a wide-angle lens (left, 24mm) where anything close to the camera is massively enlarged. Standard lenses may be less dramatic but they are more truthful.