![]() ![]() Aperture simply means 'hole' in this context, the hole that lets light pass through the lens and onto your camera's sensor. The aperture specification of a lens describes how much light it is capable of gathering. This means simply that an 18-55mm lens on an APS-C format camera covers the same angle of view as a 28-90mm lens does on a full-frame camera. These are shown for a full-frame sensor each would cover a smaller area if used with an APS-C or Four Thirds sensor.įor the sake of convenient comparison, lenses are often referred to by their ' 35mm equivalent' focal length for example a 18-55mm kit lens for APS-C may be described as a 28-90mm equivalent. ![]() SOMETHING SILIAR TO ALPHA ZOO SERIESIllustration showing the coverage given by a series of popular focal lengths. As a result, the focal lengths that are useful on one sensor format will differ from those that you'd use for the same purpose on another sensor. The effect is as is as though you've 'zoomed' the lens, but instead you've only magnified a smaller portion of its projected image. The same focal length lenses, mounted on a smaller, APS-C sensor would give a narrower, more cropped-in angle of view, and an even narrower coverage if mounted on a Micro Four Thirds format camera. In this instance it shows the effect of these lenses mounted on a full-frame camera. The image below shows how the angle of view varies with focal length. Here, we can see this lens' key specifications expressed in terms of its focal length span ('zoom range') which is 18-35mm, and its minimum aperture range, which is F3.5 at 18mm, and F4.5 at 35mm. Fixed focal length lenses which don't zoom (also known as ' prime' lenses) just have a single number ( e.g. Zoom lenses are named using two numbers which indicate the extremes of the range, for example 24-70mm for a typical kit zoom lens. ![]() The first number used to describe a lens is its focal length in combination with the camera's sensor size, this defines the angle of view covered by the lens, with smaller 'mm' numbers indicating a wider angle or more 'zoomed out' view. We'll look into each of these in more detail below. Lens mount - determines whether the lens will physically fit your camera.Format - describes the sensor size the lens is designed to work with.Image Stabilization - some lenses include optical stabilization units to counteract the blurring effects of hand shake.Aperture - expressed as 'F' or 'f/' this describes how much light the lens can gather and its ability to blur the image background.Focal length - this defines how wide or zoomed-in a view the lens provides.Luckily you can safely ignore most of them to start off with, and concentrate mainly on just a few factors: Lens names often include long lists of letters and numbers, which certainly sound impressive but can also be thoroughly confusing. Looking at the lens pages on manufacturers' websites can be a little intimidating for a budding photographer. The examples given in the rest of this article are lenses designed for full-frame bodies but we'll also discuss what impact sensor size will have. Lenses themselves know nothing of the sensor mounted behind them, but different sized sensors change the visual impact of the lens (specifically the focal length and aperture) on the final image.Īmong interchangeable lens cameras today there are three commonly-used sensor sizes: Four Thirds, APS-C and full-frame. In this guide we'll lead you step-by-step through the process of understanding the different kinds of lenses available, and choosing the right one for your needs. But with a bewildering variety of lenses out there, how do you know which ones are right for you? SOMETHING SILIAR TO ALPHA ZOO FULLIf you want to explore the full potential of your camera – and your own creativity – you should consider adding another lens or two to your collection. A camera is nothing without a lens, and while the bundled 'kit' lenses sold with many interchangeable lens cameras (ILCs) are good enough to get started, they're quite limiting. ![]()
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