[Sigma Blog] What is a Zoom Lens? And why and when to choose a Zoom Lens?

Take a look at this article about Zoom Lens from Sigma Blog!

Zoom lens are available at our store.

Source: http://blog.sigmaphoto.com/2014/what-is-a-zoom-lens/

What is a zoom lens?

A zoom lens is a type of camera lens that is offers the photographer a useful range of different focal lengths in a single lens. This is in comparison to a prime lens, which only offers a single focal length. A zoom lens allows for quick and easy re-framing of a scene while staying in the same physical position. Sigma offers a line of over 20 zoom lenses for DSLR photographers, ranging from wide angle zoom lensessupertelephoto zoom lenses, andhigh-zoom ratio all-in-one lenses for both full-frame (DG) and APS-C (DC) digital cameras.

Sigma offers a great variety of zoom lenses. (Lenses are not shown to scale in this display.)

Sigma offers a great variety of zoom lenses. (Lenses are not shown to scale in this display.)

Which Sigma zoom lenses are right for you depends on your photographic intentions, budgets, and overall size constraints. In this article, we are going to explore many facets of zoom lenses for digital photography and explain the terminology, key features and benefits of the different types of zoom lens. We’re also going to showcase images made with a variety of Sigma zoom lenses to illustrate key concepts.

Zoom Ratio, and Constant-Aperture or Variable-Aperture Zoom lenses

Zoom lenses always feature two focal lengths in the name which indicate the shortest and longest focal lengths in relation to the 35mm/full-frame sensor. To determine the overall zoom ratio of the lens, simply divide the longest focal length by the shortest. So, for example, the Sigma 18-35mm F1.8 DC HSM and the 8-16mm F3.5-4.5are both examples of 2x zoom lenses:  35 divided by 16 equals  1.95, and 16 divided by 8 equals 2.  (It is common practice to round to the nearest whole number or major fraction.)

Fall leaves seen through the Sigma 18-35mm F1.8 DC HSM lens at 24mm. 1/400 F4.5 ISO 100 on a Canon EOS Rebel T3i.

Fall leaves seen through the Sigma 18-35mm F1.8 DC HSM lens at 24mm. 1/400 F4.5 ISO 100 on a Canon EOS Rebel T3i.

Same scene, seen through the same lens, this time fully zoomed to 35mm. Notice how the background is more abstract, even with the same F4.5 aperture as the previous shot at a wider field of view. A quick twist of the zoom ring can easily change the overall image characteristics, and this is a key advantage of zoom lenses.

To read the full article, please visit the original source here: http://blog.sigmaphoto.com/2014/what-is-a-zoom-lens/ 

About apssblog

Photo-Shop-Studio offers much more than normal on-line shopping. Our team with over 30 years experience in photography industry can provide you full services with technical assistance to explore your photographic interests or professional requirements. For all enquiries, please call us on (02)9560 8830 or send us a email to info@photo-shop-studio.com.au For customers who prefer the hands on feel of testing a product and also for those who prefer in-store pickup of your internet orders, you are welcome to visit our shop at 325 Parramatta Road, Leichhardt, NSW2040. With a large inventory of various brands and products on display at our showroom, you can check and test out exactly what you want before you buy.

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