Camera Lenses 2

If you’re new to photography, the vast array of lenses on the market might seem a little daunting. There exists not just a range of focal lengths, from the super-wide to the super-long, but even several variations on a single focal length, not to mention zoom lenses of all kinds. 

WIDE ANGLE

Wide-angle lenses have three classes: Wide, ultra-wide, and fish-eye.You can tell a fish-eye lens by looking at it because the front element bows outwards, allowing it to see as wide as 180 degrees. This gives the signature fish-eye effect which bends all straight lines around the center and creates a circular effect in the image. These lenses are fantastic for certain purposes, but are often overused without real purpose – use them with caution.

An ultra-wide angle lens is one which has a focal length shorter than 20mm, but is built with internal lenses which are meant to correct the fish-eye distortion; these are sometimes referred to as “aspherical”.

A regular wide-angle lens is defined as anything shorter than 35mm. These can capture wide scenes, and have a much larger depth of field (more will be in focus, from the foreground to the background). This, added to their expansive angle of view, make them the ideal choice for sprawling landscapes, as well as tight interiors.

NORMAL LENSES

A “normal lens”, as he mentions, is one that sees in a similar proportion to the human eye. These are typically between 35mm and 50mm and are among the most common prime lenses on the market (most brands sell a 50mm f/1.8 for under $250). They are wonderful for travel and street photography, because the images strike us as something that we would see with our own eye.

TELEPHOTO LENSES

Telephoto lenses are technically defined as anything exceeding 50mm, though the term is usually used to describe lenses which are beyond 100mm; the ranges between 50-100mm are more commonly referred to as “portrait lenses”, because that is what they excel at and are primarily used for. Just the opposite of wide-angle lenses, telephotos shorten the depth of field, enabling you to isolate your subjects from the background with shallow focus; this is when only a short plane is sharp, and everything in front of or behind that plane falls rapidly into blur.

PRIME LENSES

A prime lens has no zoom – it is one focal length, and one only. Because the lens is manufactured precisely to provide this one length, and doesn’t have the moving pieces and mechanisms required to zoom, they can be tack sharp. Again, because of the relative simplicity of their build, they can have larger apertures (the size of the opening in the lens), and therefore are much more useful for indoor and low-light photography. If crisp and clear images are more important to you than convenience, these are the lenses you want to look at.

ZOOM LENSES

Most consumer-level and camera kit lenses will have a variable focal length – you can turn or slide them in order to zoom in and out. These are preferred by most travelers and hobbyists, because one or two lenses will give you an entire range, and you don’t need to be carrying a big, heavy camera bag and switching between ultra-wide and wide, or normal and telephoto. You can even find “superzooms” such as an 18-200mm, which cover the entire range that most people will ever need. Of course, the jack-of-all-trades is master of none, and these lenses won’t deliver such perfection as a prime is capable of – though many are very good, and getting better with each generation.

MACRO

The macro lens has an intense level of magnification, capable of picking out the tiniest details and enhancing them larger than we can see with our own eyes. It’s thanks to these lenses that we’ve been able to see the texture of a fly’s face, or a flower’s pollen spores – such developments which have enhanced the human understanding of the world around us in immeasurable ways.

APERTURE

One thing that isn’t addressed in the video is: just what does it mean to say a lens is f4, or f3.5-5.6? This number is called the maximum aperture, and it refers to how large the opening can be that allows light to pass through the lens – the smaller the number, the larger the hole; the larger the hole, the more light is let in; the more light is let in, the better images you can get in low light. On a zoom lens, this will be expressed in a range – on the 18-55mm f3.5-5.6, the maximum aperture at 18mm will be f3.5, while the maximum at 55mm is f5.6.

The size of this opening also has a direct effect on depth of field (as mentioned before – how much is in focus, from foreground to background). The larger the aperture (smaller number), the less will be in focus (“shallow depth of field”), which enables beautiful isolation of pieces of a photograph, or what is called “selective focus”, such as in the image of the lizard above. However, because the larger hole demands more perfection in the lens construction, it can be very expensive to achieve this, which is reflected in the price of a lens.