Back to sigmaphoto. Home What is a Zoom Lens? Fall leaves seen through the Sigma mm F1. Same scene, seen through the same lens, this time fully zoomed to 35mm. Notice how the background is more abstract, even with the same F4. A quick twist of the zoom ring can easily change the feel of the scene, and this is a key advantage of zoom lenses.
Here is a view of a rock quarry made with the vintage Sigma mm F2. Look at the shortest and longest focal length to determine the zoom ratio of a lens. The Sigma mm F3. This image was made wide-open at F3. Now, here the mm is zoomed all the way to mm mm full-frame equivalent. Divide the longest focal length by the shortest to determine the total zoom ratio of this lens. As you can see, this offers a much greater difference in the zoom ratio than the 3x zoom lens example shown earlier.
This image was made wide-open, at F6. This is Sandy Hook lighthouse, captured in Infrared on the Sigma SD1 at 17mm, the shortest focal length on this zoom lens.
This helicopter was captured with the Sigma mm F2. Transit of Venus, captured with the Sigma mm F4. The forecast called for clouds the whole day this last-in-a-lifetime event was taking place; but late in the afternoon, the clouds broke just enough to grab seven frames through the Sigma SD1 at mm at F At mm equivalent on the Foveon APS-C sensor, this was a lot of reach in a lens I could quickly mobilize when the opportunity appeared.
Eastern Willets, seen through the 10x variable-aperture Sigma mm zoom lens at 75mm on the Sigma SD1. And here is a close-up shot of the Eastern Willet, from the same spot on the beach, by zooming this lens all the way to mm. Notice how these two images from the same spot, with the same lens, feel so different to one another. Each Sigma zoom lens is uniquely designed to create the best possible images throughout its zoom range.
What is Optical Stabilizer? As you can see, it was long enough to blur the face of the person climbing down the stairs of the Sandy Hook lighthouse. Without OS, this shot would show serious camera-shake blur when hand-held at such a slow shutter speed. Why Use Tripod Collars? Versatility is the Key to the Appeal of the Zoom lens Zoom lenses are designed to offer the photographer a great deal of flexibility in composition and framing without ever having to change lenses, or even physical position, for that matter.
It is a very different image made just by zooming in and kneeling down to grab a close detail. And keeping the lens at 70mm, but focusing a bit farther away and into the morning sun creates yet another very different image and takeaway from the same spot. Notice how the repetitive details get more abstract as your eye migrates upward through the frame.
The depth of field in this image, made fully zoomed with the Sigma mm F2. At 18mm with the Sigma mm F3. Look at the horizon near the right edge of the frame and notice the red wing blackbird and the lighthouse. One lens, on scene, two very different photos taken moments apart thanks to the versatility of this high-ratio zoom lens! Google Earth is a great tool for photographers! If you look very closely at this detail of the 16mm framing, you can just make out a hint of the top of the Lighthouse peeking out from between the branches.
Here we are seeing through the Sigma mm F2. The distant lighthouse is still a very small background detail at this focal length and distance. At mm on the Sigma mm F2. Here, we are zoomed in to mm on the mm. Notice how blurred the foreground branches are at this focal length and focal distance. And finally, here is the lighthouse from a half-mile away at mm, again at F4 the Sigma mm F2.
Focal length, aperture, and focal distance all play a role in object size in the frame and the presentation and apparent relationship of near and far details Zoom lens construction technology has come a very long way over the past forty years. The technical information for the Sigma mm F2. In general, barrel and pincushion distortion effects are most noticeable in images that have crisp straight lines near the edges of the frame.
This infrared scene was captured with the Sigma SD1 and the mm F3. The longer and more considered answer is that you need to think about the type of photographs you currently take. You need to understand how different lenses could improve your current photos and allow you to take ones that you currently can't.
If that all sounds a bit confusing, read on. The almost sentence-long collection of letters and numbers on the side of a lens barrel can tell you all sorts of things about a lens. But the details which you should probably pay the most attention to are those which detail the focal length, maximum aperture, lens mount and format type. Focal length is expressed in mm and a higher number means a bigger zoom, while a lower number mean the lens can be used for wider shots. As a rough reference, the human eye is said to see about the equivalent of mm on a full frame camera more on that later.
A number lower than mm will take in a bigger view than you naturally see, while higher numbers mean focus will be on a smaller aspect of your view. If the lens has a focal length range with two numbers say mm this means it's a zoom lens and is capable of zooming and being used at any point across that range.
However, if there is a single focal length number 50 mm for instance it's a prime lens, so taking in more or less of the view will require you to get closer or further away from your subject. Traditionally, primes have been considered to be optically superior to zooms, because trade-offs have to be made when producing zoom lenses. But that's not to say that some zooms are not better than some prime lenses.
To make understanding focal length more difficult, the same focal length lens gives different views on cameras with various sensor sizes, because of the crop factor the sensor only takes up part of the projected image.
As a result, many manufactures give a 35 mm-format equivalent on lenses designed for cameras with smaller sensors and in this article descriptions are based on on 35 mm-format.
Therefore, if your camera has a smaller sensor, and there's a good chance it does, you'll need to consider this when deciding which lens you need. If you're using a full frame camera there's no calculation needed, a lens will give you the field of view you'd expect from its number.
On a Nikon 1 it would act like a 95 mm lens does on a full frame camera. Lenses with larger maximum apertures slightly confusingly these are the ones with lower numbers are capable of gathering more light. As a F1. Some zoom lenses have a variable maximum aperture meaning that it changes depending on focal length. So, while a mm F3. It goes without saying that you want to buy a lens that will attach on your camera, and this is known as the lens mount.
Camera manufacturers generally make lenses with proprietry mounts which will only fit their devices, sometimes having multiple lens mounts for different camera lines. The major exception to this is Micro Four Thirds lenses which can be used on respective Olympus and Panasonic cameras.
Third party manufacturers also make lenses with mounts to fit various brands. It's important to know which mount your camera uses before heading out to buy a lens.
In addition to being able to mount the lens on your camera, you need to be sure it will produce an image big enough to cover the image sensor. Because different cameras use different size sensors , manufacturers produce specific lenses to work with them. Meanwhile, FX lenses cover the full frame and can also be used on DX and even Nikon 1 cameras with an adapter. This is done because lenses designed for smaller sensors can be physically smaller and lighter themselves.
Lenses are generally categorized by their focal range or specific function if they're a specialist lens. Below we've taken a look at a few of the most common types of lens, thought about the characteristics their images are said to have, and considered how they can be used. What they are: Ultra Wide angle lenses have a focal length of around less than 24 mm in 35 mm-format , this means they can take in a wider scene than is typical, though they're not only about getting all of a subject into a shot.
Rectilinear ultra wides help keep straight lines, just that, while fisheyes will reproduce buildings with curved walls. Image characteristics: Because of the wide field of view, shots with ultra wide angle lenses typically feature a large depth of field. Images tend to pull in subjects that are close, and push away more distant ones making them appear further apart. Perspective distortion of ultra wides can give falling-building-syndrome where vertical lines converge but this can be corrected in post-processing, or minimized with good technique.
What they are used for: While often seen as a specialist lens, ultra wide angles can be used in a number of ways. Typical uses include landscape, architecture and interior photography. Even the distortion can be used creatively, especially when using fisheye lenses. What they are: Typically covering a focal length between 24 mm and 35 mm, Wide Angle lenses are available as primes or zooms and come with either variable or fixed maximum aperture.
Offering a wide field of view, they often also boast close minimum focusing distances. Image characteristics: Wide angle photographs can magnify the perceived distance between subjects in the foreground and background. Wide angles suffer less distortion than their ultra wide counterparts, but you still get an exaggeration of lines and curves which can be used artistically.
What they are used for: Many people only reach for a wide angle lens when trying to get the whole of a subject in frame, whether that's a building, a large group of people or a landscape. However, while those are perfectly good uses of one, they can also be used for interesting portraits where you want to place a subject in a situation. Just be careful not to distort faces unflatteringly by shooting too close. What the are : The kit lens your DSLR or interchangeable lens mirrorless camera came with is probably an example of a standard zoom lens, covering a focal range of around mm.
Ones with better optics and faster maximum apertures are also available. Many photographers consider a 50 mm prime in mm-format as a normal lens, as it's said to reproduce an image with a angle of view which feels "natural" and similar to what you see with your eyes - even thought this isn't technically true. Image characteristics: Standard zoom lenses and normal primes sit between wide angles and telephotos in terms of image characteristics and are much more like you see with the human eye.
Normal prime lenses tend to have faster maximum apertures which can allow for a shallow depth of field and lower light shooting. What they are used for: As their name would suggest, normal or standard lenses are versatile lenses which can be used for almost all sorts of photography whether street, documentary, landscape, or portrait. Because normal prime lenses tend to feature faster maximum apertures, they allow you to shoot with a shallower depth of field and in lower light.
What they are: Telephoto lenses are those with a focal length in excess of 70 mm, though many people would argue that "true" telephoto lenses are ones which exceed mm. They focus on a much narrower field of view than other lenses, which means they are good for focusing in on specific details or distant subjects. They are generally larger and heavier than equally specified wider lenses. Image characteristics: Because they have a narrower angle of view, telephoto lenses bring far away subjects closer.
They can also have the effect of compressing the sense of distance in a scene and making objects appear closer together. A narrow depth of field means that a subject can be in focus with a blurred background and foreground. What they are used for: In addition to being used to photograph subjects you can't or don't want to get close to - like sports or wildlife - telephoto lenses can be used for shooting portraits and even landscapes where their normalization of relative size can be used to give a sense of scale.
What they are : Superzooms are do-it-all lenses which cover focal lengths from wide to telephoto. They can be good for uses in situations where you can't or don't want to be changing lenses and they normally change in length as you zoom.
Image characteristics: Because compromises have had to be made producing a do-it-all lens, superzooms do not have the same image quality of more dedicated lenses and often have slower and variable maximum apertures.
What they are used for: Offering a one-lens package, superzooms come into their own if you can't or don't want to change lenses. This could be when in situations where it wouldn't be safe to switch lenses, or when travelling - you don't necessarily want to be weighed down by five lenses when on holiday with the family. What they are : One of the more specialist lenses, marco lenses are technically those which are capable of reproduction ratios greater than However, the term is frequently used to refer to any lens which can be used for extreme close-up photography.
Macro lenses typically have focal lengths somewhere between mm. Image characteristics: Macro lenses normally have excellent image sharpness, though it's worth noting that when working at close distances they also have a tiny depth of field. Lenses are an essential piece of equipment in any photographers bag, so it's worth taking the time to understand the different types. These two classes in particular explain the differences between various focal lengths and shows you the results from each.
Our Equipment section also provides a number of short, informational videos with valuable tips for cleaning and looking after your lenses, which you may find useful. You must be logged in to post a comment. Camera Lenses Choosing the right lens for you. Camera lens buying guide - How to choose the right lens.
Camera lenses explained. Camera lens types. Choosing the right lens for the job is essential, so it's important to understand different lenses and what each one is best for. Prime vs Zoom Lenses. Prime lenses Prime lenses are lenses that feature a fixed focal length. Much of my product photography is done using prime lenses, including this shot, which was taken using a Canon mm f2.
Zoom lenses Zoom lenses are powerful tools that cover a variety of needs. This image was taken using a Canon mm f2. Focal lengths. Telephoto lenses offer a variety of focal lengths, which makes them a good choice for different subjects. Sensor type. Watch: Full frame versus crop sensor Before buying any lens, you should find out your camera's crop factor and use it to calculate the lens's effective focal length. Lenses with wider apertures allow more light through to the sensor and are a good choice for when you want a shallow depth of field.
Image stabilisation. Although most lenses feature autofocus, I still shoot a lot of my work using manual focus. How do I choose the right lens? Lenses for portrait photography: Hasselblad 80mm f2. I often use the Hasselblad 28mm and 35mm lenses for landscape photography.
Buying second hand lenses. Tips for buying second hand lenses. All rights reserved. No content on this page may be used or shared by third parties. Recommended Content. Lens Choices for Studio Work.
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