A Closer Look at DSLR Lenses

by Bill Jones

If you make the decision to get farther into digital photography and you purchase a DSLR camera, then do not make the mistake that so many do. Many different people purchase one of these cameras and then never move beyond the kit lens that it came with. However, the whole purpose of owning a Single Lens Reflex camera is having the ability of interchangeable lenses. This is definitely something that you want to take advantage of. There are so many lenses out there with so many different options and capabilities. If you stay with just one lens, you are certainly missing out on chances at amazing digital photography.

However, at the same time, you do not want to fall victim to something that is so common to people in digital photography that it has its own official name: Lens Lust. Those who have been infected with Lens Lust will find themselves wanting more and more lenses and they may even be dropping money on lenses that they simply do not need. The best thing to do is understand the lenses. Understand what you need for your digital photography. Then, only purchase lenses that you will actually need or use.

The Lens Designations

When you are shopping for lenses, you will notice that they all include a set of letters like initials. You may be wondering what those initials mean. Actually, they signify something very important and they definitely are something that you need to be familiar with. Each vendor (maker) of DSLR lenses will use a set of initials to designate between cropped and full frame lenses. Here are those designations.

Canon —EF (full frame), EF-S (cropped)
Nikon – FX (full frame), DX (cropped)
Sigma – DG (full frame), DC (cropped)
Sony – No Designation (full frame), DT (cropped)
Tamron – Di (full frame), Di-II (cropped)

The Three Main Lens Designs

Many people do not realize this, but SLR lenses are not all the same in design. While they may use the same components, the lenses are different in how they work, and this will matter when you delve more into digital photography. There are three main lens designs. By understanding them a little better, you will better be able to understand what is happening each time you take a picture.

Simple
In a simple lens design, you will find that there are two main elements to be aware of: the optical center and the focal length. The optical center, in a simple lens, will be in the exact center of the element.

Telephoto
A telephoto lens is a little different. When you look at the lens design, the optical center is actually a great deal out in front of the lens. This is how the lens is able to take a farther away image. A telephoto lens will have a much longer focal length than a simple lens.

Retro Focus
This is the type of lens design that is used to combine a wide angle lens along with a telephoto lens. In a retro focus lens, the elements are inverted. The optical center is actually behind the lens, and this means the focal length is much shorter.

Understanding Bokeh

The more you get into digital photography, the more often you are likely to hear or see the term, bokeh. This term for an element in photography is derived from the Japanese term which means “blur.” Each type of lens will produce bokeh. The question will be whether it is good or bad bokeh.

You are probably feeling a little lost now. Here is a simple way to understand bokeh. Take a look at a picture in which the subject is in focus and the background is blurred. You will see that any light points in the background have become discs of light. These discs can become extremely distracting to the image or they can actually be an artistic element. This effect is bokeh. Just what is bokeh? Here are the three traditional levels.

Good bokeh – the points of light are bright in the center and they fade away at the edges. This is good because they are considered artistic and non distracting.

Neutral bokeh – the points of light are grayish or faded in color and they fade on the edges slightly. While not the ideal choice, neutral bokeh will not necessarily ruin an image.

Bad bokeh – the points of light look like a doughnut with a dark center and harsh edges. This is extremely distracting in an image and can definitely take away from the subject.

Lenses with bad bokeh are not the optimum choice when you want to create this type of short depth of field images. These types of lenses can be better used for images that will all be in focus. For images with blurred backgrounds, choose lenses that you know have good bokeh qualities.

What to Look for in a Lens

Lenses for your digital camera are an investment and you will definitely want to choose the right ones. Just how do you know which lenses to choose? The best way to decide will be to consider different factors that are involved in the different lenses.

– Image Quality and Sharpness
– Aperture Capability
– Zoom Length
– Focusing Distance
– Focusing Speed
– Compatibility with Camera
– Autofocus
– Availability of Image Stabilization

Choosing the right lens should require a little research. You will need to know what you plan on using the lens for, and then you should choose lenses accordingly. Of course, it is a better idea to choose lenses that are fully compatible with your camera. After market lenses may not be fully compatible, and that can lead to a few issues. You may not be able to use the autofocus or the image stabilization technology. Tread carefully if you choose aftermarket lenses. By understanding lenses a little more, you can make sure to avoid that old problem of Lens Lust, but you can also make sure that you have enough lenses for your own digital photography needs.

Top image by Boqiang Liao

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1 Comment

Jessica Simmons said:

I believe that the secret of a great image lies beyond lenses. The more expensive your lens is, the greater quality of image it’ll give to you. If I’ll be able to buy a camera, I’d get a Canon because I think Canon is easy to use and has great quality.