The device is protected with extra seals to prevent failures caused by dust, raindrops, and water splashes.
2.Has a metal mount
✔Sigma 105mm F2.8 EX DG OS HSM Macro
✔Tamron SP 90mm F/2.8 Di VC USD 1:1 Macro
A metal mount is generally superior to a plastic mount as it is more durable.
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 longer maximum focal length allows you to focus in on a small part of a scene, and offers a narrower angle of view than shorter focal lengths.
A shorter minimum focal length allows you to get more of the scene in the photo, and offers a wider angle of view than longer focal lengths.
The front element doesn’t rotate. This is important if you use filters, as some such as polarising or gradient filters have to be orientated a certain way.
It comes with a lens hood so that you don’t have to buy it separately. These are used to block strong light sources, such as the sun, from the lens to prevent glare and lens flare.
The lens hood can screw onto the lens in reverse so that you can keep it on your camera at all times, ready to use.
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.