Introduction to lens acronyms
Digital SLR cameras combine the benefits of shooting in manual mode with the convenience of being able to review your images instantly without having to wait for them to come out of the darkroom.
With Photoshop and Lightroom, you carry your darkroom with you wherever you go.
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This is an incredible advantage and one that film photographers can never dream of. With newer and improved technology comes the problem of getting used to. It is a toss-up between whether technology makes our life better or more complicated. But that’s a question best left philosophers and scientists to argue and settle and is out of the scope of this article.
In this article, we shall look to understand lens technology.
One thing that has not really changed with the transition from film to digital and has actually gotten more complicated is the lens technology. Some of you will argue haven’t we seen similar changes to camera technology as well? Yes, we have but try going through all the lens acronyms without a hiccup and you will know what I am trying to get to.
For example, do you know how different a Nikkor 135mm f/2.8 DC lens is from a normal 135mm f/2.8 lens? Or for that matter what is the difference between HSM and USM? In this article, we shall look at a few of the essential acronyms that you need to know when buying a lens.
Lenses will always have the format they conform to engraved/printed on them. That’s the intended mount the lens is designed to be used with.
Nikkor lenses, for example, come with the acronyms DX or FX mentioned on them, meaning they are designed for either the smaller APS-C sensor based cameras such as the D90, the D7100, and the D3100 or for the full-frame / 35mm format for cameras such as D600, D800 respectively.
You can still use a lens designed for a 35mm (FX) camera on a DX format camera but you will only be using the center area of the image coming through the lens.
Related Post: 7 best Nikkor lenses for your DSLR camera
With the popularity of 1” sensor size cameras formats like Nikon’s 1 series (CX format) and Samsung’s NX series are fast becoming popular. Both these cameras have a 1” image sensor beating inside them. These cameras have specially made lens lines for them as well. There are a number of third party lens manufacturing companies such as Tamron, Tokina and Sigma.
They make different versions of the same lens to comply with the major mounts such as Nikon’s F mount and 1 mount, Canon’s EF and EF-S mount or Sony’s A mount and so on.
When buying a lens you will need to know the specific lens mount and accordingly choose a lens that complies with it.
Optical Image stabilization
Image stabilization or optical image stabilization is the process where certain elements of a lens are moved back and forth to bring an image in line with the sensor. This is required because the camera is never perfectly steady when being hand-held. Wind, involuntary hand movements and even the beat of one’s own heart are reasons why the camera is prone to tiny (or even major) movements while an exposure is being made.
Another advantage of using image stabilization is that you can use a slower than normal shutter speed. This ability is an advantage in less than optimum lighting conditions. Image stabilization is necessary primarily when you are shooting hand-held. If you shoot with a tripod most of the times then it is a luxury and does not warrant the premium price tag.
Related Post: Best entry-level tripods for your DSLR
Those shooting wildlife and sport tend to go with the image stabilization function because it allows them the luxury to take their camera off the tripod in a flash and then make the shot after engaging image stabilization.
Different camera makers use different names to identify their optical image stabilization systems.
Nikon and Canon are known for their lens-based image stabilization systems while Sony and Olympus make systems that are a sensor-shift type. There is a major technical difference between the two types of image stabilization, but they all essentially do the same thing.
Different lens acronyms, describing the same thing:
- VR (used by Nikon) which stands for Vibration Reduction (VR), does the same thing as
- OIS or optical image stabilization used by Fuji or
- Optical Steady Shot (OSS) used by Sony and
- IS or Image Stabilization used by Canon does.
Wide-angle vs telephoto vs micro vs standard
Wide angle lenses are those which give you a wider field of view. You can see more when looking through the viewfinder and that’s what makes these lenses ideal for landscape, seascapes, cityscapes and anything else where you need to capture a large chunk of the scene.
Anything that has a focal length of less than 35mm is considered as a wide angle lens.
Telephoto lenses, on the other hand, are those which allow you to see further. These are lenses that have a special group of glass inside them that allows the lens to be able to see further despite the overall length being much smaller. Telephoto lenses will offer you a very small angle of view when compared to wide angle lenses. The further the lens can see the narrower the angle of view will become.
Micro or macro lenses are those which offer a true to life or larger than life perspective of things. These are lenses that can focus very close and are thus used primarily for photographing small subjects. Standard lenses are termed as such as they offer an angle of view that is similar to what the human eye sees.
Related Post: Finding the best Canon Macro Lens
Prime vs zoom
Primes are fixed focal length lenses
They don’t zoom. The only thing you can do with them is to adjust the focus by turning the manual focus ring.
Zoom lenses, on the other hand are those which come with a variable focal length. There are some advantages to using a zoom lens obviously. These are definitely more versatile and you could cover more with a single lens. The only problem with zoom lenses are that sometimes (especially for the cheaper lenses) the optical quality is not that sharp as prime lenses.
Prime vs. Zoom
To their credit prime lenses are known for their superb optical quality. Naturally, zoom lenses will have a focal length range mentioned on the barrel such as 18-55mm. Prime lenses, on the other hand will have only a single focal length mentioned on the barrel.
Related Post: Prime vs. Zoom: Which one should you choose?
Aperture or the opening of the lens is through which light travels and then hits the sensor inside the camera. The larger the opening, the more light is able to go through.
In other words, the larger opening allows for more light which is suitable especially for low light situations. Aperture controls one more aspect of your images and that is the depth of field.
Depth of field denotes the extent of the image that is in focus.
With wider aperture depth of field becomes thin. Conversely, with smaller apertures, the depth of field becomes larger. Aperture is denoted in f-stops. F/2 is an aperture that is double the size of f/2.8, which in turn is double the size of f/4.
You will come across terms such as SWM, or USM or HSM.
Though they sound quite intimidating, these basically mean the same thing. These are terms used by companies to advertise that their lenses are super quiet when auto-focusing. These have nothing to do with the speed of auto-focusing though, although with very new technology efficiency and speed both improves.
Anyways, let’s spell out these lens acronyms:
- Nikkor’s SWM stands for Silent Wave Motor
- Canon’s USM stands for ultra-sonic motor and
- Sigma’s HSM stands for Hypersonic Motor.
An additional advantage of quieter auto-focusing is that when you are shooting videos the deafening noise that normal lenses make is not recorded in the footage.