Camera Zoom Lenses


Camera Zoom Lenses

Camera Zoom Lenses

Camera Zoom Lenses


Manufacturers tend to make certain specifications of a camera become more highlighted to help you easily make purchasing decisions. For example, they may emphasize on the large sizes of LCD screen or the high resolution.

However, you should not base on these numbers to evaluate the entire camera, especially the highlights about the zoom lens for a digital model. There are two types of the zoom lens – it is the digital zoom and optical zoom. Those types of zoom are much different from each, so you should have some thorough consideration. To tell you about those two types, only the optical zoom is persistently useful for photographers.

Commonly, you will see the zoom lens extending from the bodies of cameras. However, this is not always the case. For several digital models, it only requires you to make adjustments on the zoom lens within the camera body.  The information that I have mentioned in the following paragraphs will help you understand more about the zoom lenses and you yourself can make right conclusions about the digital and optical zoom lenses.

Optical Zoom

To understand what the Optical zoom is, you cannot help ignoring the term “focal length”. The focal length is measured from the image sensor to the center of the lens. And the actual increase of this focal length is measured by the Optical zoom. By extending the lens in a longer distance from the image sensor inside the body, you will see the increase of the zoom. That is because a smaller part of the scene hits the image sensor, leading to magnification.

There will be a smooth zoom when you are using the optical zoom. This means that it is possible to stop the zoom any time along the total length when you want to make any more specific zoom. The stops may be distinctive in several digital models during the length. The number of these stops is often between four and seven partial zoom positions.

Digital Zoom

Actually, the measurement of a digital zoom has not meaning for most photography situations. With the digital zoom, firstly, the photo is captured and then, the camera crops calculate the number of pixels to make for the zoomed photos. It is to artificially produce photos over short distances. With this type of zoom, the number of separate pixels will be magnified or removed, which can result in lowering the image quality.

The above function is similar to the way you use a software to edit your photos on your computer after taking the photo. If you find that it takes time to edit photos with the software, you will find the digital zoom very useful, in which you can shoot photos at the high resolution, then just removing a number of pixels and turn the resolution to the lower level, you can easily have pretty nice artificial photos over shot distances. Undoubtly, the digital zoom is useful in a limited number of situations.

Understanding Zoom Measurement

In the specification list of a digital model, you can see both the measurement of the two types in the format of an “X” character, for example, 5X or 10X. The magnification is higher for the larger numbers.

But don’t forget that all the measurement in the same specification like “5X” has the same meaning. The measurement is calculated from this extreme to that other of the lens abilities. Or you can understand that there is a “multiplier” or in another words, the difference between the maximum and minimum number of the focal length measurement. For instance, if the minimum measurement number of the focal length is 35 for an optical zoom lens measured 10X, the maximum number would be 350mm. However, if there are some extra wide-angle offerings in a digital model and its minimum focal length is 28m, the maximum one would be 280mm for an optical zoom measured 10X.

To avoid the confusion, the manufacturers should specify the focal length in a clear format in the specification list, for example, to “35mm film equivalent: 28mm-280mm.” Commonly, without magnification or shooting capacity at wide angles, the measurement of 50mm is a “normal” number. It will be very essential for you to compare the 35mm film equivalent number between this lens and the other lens if you are attempting to put the overall zoom range of a specific lens in comparison with other lens. You should look at the number on the right. Please make sure that you’re not confused about the zoom lens measurement.

Lenses which are interchangeable

Commonly, you’ll often see a zoom lens which is already built in the cameras that are targeted at photographers at the beginning and intermediate levels. However, Interchangeable lenses are more and more common for most digital SLR (DSLR) models. For a DSLR mode, if the zoom abilities and a wide angle are not offered as you want, additional lenses can be the good solution to have the larger zoom range and nicer wide-angle selections.

The price tag of DSLR models is higher than that of point-and-shoot models. The DSLR is often targeted at photographers at the intermediate or advanced levels.

There is not a “X” number to represent the measurement of the zoom lens in most DSLR lenses. And you will see the focal length right in the name of the DSLR lens. The focal length, not an X zoom number is also listed with the lens used in DIL (digital interchangeable lens) cameras, or also called mirrorless interchangeable lens cameras.

Some Zoom Lens Drawbacks

An optical zoom lens of the large size is nice and very useful in certain situations, which you often see in point and shoot models. But don’t forget some of small drawbacks.

  • The noise problem. When you maximize the focal length of a zoom lens, the image quality may be lowered. This is pretty common for budget-priced cameras aimed at the beginning level. The noise represents a collection of stray pixels which do not record accurately. You’ll often see edges in purple with this kind of photo.
  • The pincushioning problem.When you set the zoom to the maximum level, you may encounter the pincushioning problem, which is a distortion where you stretch the left and right edges of the image. You’ll see horizontal lines become a bit curved toward the frame center. This problem is more common for budget-priced models aimed at the beginning level with large zoom lenses.
  • The shuttering speed is slower. When a lenses is adjusted to the maximum zoom capability, the shuttering speed is often slower, which can result in blurry photos. Because of this drawback, you may not able to catch spontaneous photo. This slower shuttering speed is caused by the longer time that the camera needs to focus on the photos with the zoom setting at the maximum level. Especially in low light photography, the problem becomes even worse.
  • A tripod is required. Because of the zoom lens extended to the maximum level, the camera shake often appear. If there is the image stabilization feature with your camera, the problem can be correct. A tripod is a nice solution to help you avoid the image blurriness caused by camera shake.

Stay smart

Don’t be fooled by the highlighted specifications of the cameras. The measurement of the digital zoom and optical zoom can be combined because the manufacturers want to show a large number to attract your attention.

You should only take a look at the optical zoom measurement. This measurement number may be displayed in the back panel of the camera box together with numbers of other specifications. You also spend a little time figuring out the optical zoom measurement of a specific model.

To fully understand the zoom types can help you give the best decision. Be ready to thoroughly find out about the zoom capacity of a model before purchasing any camera.


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