We consider a lower weight better because lighter devices are more comfortable to carry. A lower weight is also an advantage for home appliances, as it makes transportation easier, and for many other types of products.
A telephoto lens allows you to zoom in on far away objects. This is particularly useful when you need to photograph a subject from a distance, such as wildlife photography, or even in some cases street photography where you can’t get near the subject.
Optical image stabilization uses gyroscopic sensors to detect the vibrations of the camera. The lens adjusts the optical path accordingly, ensuring that any type of motion blur is corrected before the sensor captures the image.
With a wider aperture the sensor can capture more light, helping to avoid blur by enabling a faster shutter speed. It also provides a shallow depth of field, allowing you to blur the background to focus attention on the subject.
Similar to the number of aperture blades, rounded blades affect the way the light gets through to the sensor. Rounded blades, often only found on more expensive lenses, improve the appearance of the out-of-focus areas. This allows you to attain better, softer looking bokeh in your photos.
The aperture controls how much light gets through to the camera’s sensor. More blades is often an indicator of a better quality lens. It also allows you to achieve much nicer looking bokeh when blurring out your background, whereas a lens with less blades will often produce harsher, more polygonal bokeh.
Many lenses allow you to focus to infinity. This is essential when you wish to take photos including far off objects, such as when shooting landscapes, in order to make sure everything is sharp and in focus.