Telephoto lenses. They have a narrower field of view than wide angle lenses; this normalizes the relative distance and size between objects placed at different distances if compared with wide angle lenses: closest objects will appear similar to farer ones because, due the narrow field of view, far objects will cover a large portion of the angle and the distance will appear compressed. They are normally used to photograph subjects you are not able to approach filling the frame with them, as in wildlife or sport photography. But this use would be very reductive. Telephoto lenses can be used in landscape photography for example, filling the frame with a single element or selecting a portion of landscape; or you can take advantage of the appearance of compressed distance and play with different layers of landscape compositions or exaggerate the density of a pattern. The most known aesthetic characteristic of telephoto lenses is the shallow depth of field they can achieve at a given distance (the compressed distance enhance and magnify the out of focus area), which is great for isolating subjects from the background, very useful for portraits.
Prime and zoom lenses. While the prime lenses have a fixed focal length, zoom lenses have a variable one. Prime lenses tends to be smaller and, generally, they offer a better optical performance than zoom because the light passes trough less optical elements, even if nowadays the difference is not that big as it used to be. Diaphragm aperture thou, will always be bigger with prime lenses and it may varies in the zoom lenses, according to the focal length it is used. On the other side, zoom lenses are practical for the kind of photography in which you have to constantly switch from one focal length to another. So which one should you choose? As always, it depends on you and your photography, but remember to stay functional. For the kind of photos I make, I prefer prime lenses and I think that the best zoom are my feet (because I like better the change of relative perspective than magnifying the whole image), while for some one else it is more practical to carry and use 3 zoom lenses than 6 or 7 different prime lenses... 
A camera lens is an optical device which captures the light in a scene and focus it onto the film or digital sensor. It is made of several lens elements: extra refractive glass (which alters the angle of refractive light), aspherical elements (correcting into focus peripheral rays), low dispersion elements (which reduce chromatic aberration), anomalous dispersion elements (to control the amount of diffraction of light for a specific color range). The quality of these elements will determine the whole quality of lens and image captured.
Standard lenses. When a lens has a focal depth in the range between 35mm and 70mm it is called standard lens because it resembles the way the human eye sees things (about 50mm on a 35mm film): subjects will have the same size and the same proportions as seen trough the eyes. They are general purpose lenses, ideal for the kind of shots people normally take. This is the range that the kit zoom lenses supplied with the camera cover: these are very cheap lenses that do their job but the quality is quite poor; so, if you want to get any serious about photography, change them!
Wide-angle lenses. When a lens has a focal length minor than 35mm it is considered a wide-angle. Most people say that they use these lenses to fit the scene in the shot when they can't move further away: don't listen to them! This use is very reductive for a wide angle lens; photographers use it for the opposite reason: to get closer to the subject (street photographers make great use of these lenses). The wider vision and the really close minimum focus distance are characteristics that play in favour of creativity. Wide-angle lenses exaggerates the relative proportion of objects at different distance, making the closer one appear bigger; this emphasizes objects in the foreground but can turn a portrait in a caricature. Line and curves are exaggerated too due to the barrel distortion; photographing converging lines can be tricky (you should always aim to the horizon to avoid them or correcting them with an edition software if you don't have a tilt-shift lens). One more thing to take care of while shooting with wide-angle lenses is the light changes throughout the image due to wide portion of the scene in the frame, both horizontally (this variation can be corrected with GDN filter or bracketing for HDR) and vertically attention to the position of the light source is needed: the closer the light source is to the frame, the whiter will be the image (think of a clear sky, with the sun out of frame, which turns from deep blue to white).
But the characteristic of Smith's cinematography which is predominant throughout the film is the use of colored filters on light. In order to recreate the ambient of Bangkok and of the places where most of the scenes where shots, lights are filtered with red gels. Sometimes different colours filters, mainly blue, are used so colour contrast is strongly increased. There are scenes, like the fight one, lit with a red tone ambient light while the key light lighting the characters is white: bright neons and strong reds coexist to transmit the feeling of a city and a story filled up with blood, eroticism, violence and darkness.
Camera movements are dosed and imperceptible helping the audience to stay in the story, a purpose also achieved by the focal lengths used, never too wide nor too telephoto, always staying within the normal range of the 50mm, avoiding perspective distortions and offering a more natural look.
La Vie d'Adèle is translated in English as Blue is the Warmest Colour for a reason: the use of this colour throughout the film, an use which is, in a cinematographic point of view, very interesting. Normally blue is associated with coldness and distance not with warmth, while the colour representing love is red. The director and the cinematographer changed this relationship because they wanted to go further: in fact, blue is also the colour of freedom and the future. It is freedom what Adèle looks for when she first sees Emma, freedom for expressing her true feelings. This is what Emma's hair colour represents. She is the future for Adèle. That is why, in the gay bar, the first thing we see of Emma is the blue hair popping out from the darkness, that is why the first time Adèle and Emma makes love the linen of the bed are blue.
The way of lighting is as natural as possible, along with the general feel of realism of the film. Artificial lights are reinforced and softened but there's not a specific regard for exposure: characters, when moving, easily fall into sub-exposure or overexposure which, obviously helps with the purpose of the film.
Camera barely moves limiting itself to witness the story developing in front of the lens: we always know were we are and what we have to look at. Once again an academic way of shooting. Focal lens choice is pretty correct, though I missed the use of tilt shift lenses in a couple of shots where I found converging lines too disturbing.
The difficulty Lubezki found was that he had to match all the CGI work: the only things "real" on screen are faces, everything else (including hands and legs) is computer generated; characters don't stand still, they float gently or move and change direction in space so the light had to match perfectly with the background: different speeds in movement, different contrast or wrong density would have broken the natural feel and the film would have not worked as it does. To make things easier, Lubezki created a box with LED screen and they shoot the actors inside of it: the LEDS were projecting the backgrounds of the scenes, lighting the actors and offering them visual references for acting (which a green screen would not offer).
John Alcott used to define himself as a natural light cameraman: he managed to master light to naturally light the scene in all of the features he DP'd and, of course, Barry Lyndon is no exception; in fact it was the first historical film to be lit in a natural way: lighting in a more theatrical way was the trend at that time for that kind of features. Throughout Barry Lyndon, there's a constant feeling of natural light coming through the windows of the locations simulated by Mini-Bruts always placed outside the houses where they shot. Anyway, there are some scenes, like the one with Barry and Captain Potzodof, lit with light placed on top of their head which is no really justified nor natural.
But, the most interesting and probably most technically difficult scenes to shoot were definitely the candle lights scenes. The naturalism in the way of lighting reaches its extreme because no natural light was used whatsoever: the scenes are lit exclusively by candles, which was something technically impossible given the available means of those years. But Kubrick's stubbornness and Ed DiGiulio's expertise made history. Kubrick discovered some Zeiss lenses which were designed for the Hasselblad NASA took to the expedition to the Moon and which had a maximum aperture of ƒ 0.7. DiGiulio made the necessary adjustments to fit the Mitchell camera. 
While at the station, the Emperor try to commit suicide, which is itself a symbol of death and rebirth, and we see the first colour: the red of the blood. The following scene opens with big red doors opening; the baby emperor is taken away from her mother; all this scenes have red tones. Red is the first colour of the chromatic scale. It symbolizes the birth, the vital impulse, the start of every thing (later, when the emperor gets married, red will be the predominant colour in objects in the scene). In the first scene it also symbolizes, of course, Communism and its effects on the Emperor
The second colour is orange. It is associated with the range of age between 5 and 8 years; it leads us into the life, it is the warmth of the family, the domestic colour. In the scenes with orange tone, Pu Yi arrives to the Forbidden City, to his new family.
Pu Yi is still a child when he becomes emperor: the tone of the scene becomes yellow. Yellow can be associated to 10 to 15 years of age; it is the colour of puberty, it's intuition and awareness. It is the colour of light, it symbolizes the sun, the divine and its presence, it's the colour of the empire. Storaro uses it throughout the film not only as a tone but even placing in the scene objects of this colour, like the scene of the little emperor playing with the yellow banner which lifts up revealing the courtyard of the Forbidden City full of eunuchs: the rise of the emperor above his subjects.
Till this moment the chromatic world of the film is quite poor: red, orange and yellow, alternated with the grey of the scenes of the prisons. Pu Yi has been living in the Forbidden City, ignoring the world outside it; when he starts to acknowledge the existence of that world, the chromatic scale expands along with this knowledge. This change is represented by green, the colour of spring, of the nature that flourishes, of life that starts again. It represents the age around the 20 years, the study, the knowledge that takes us to freedom. It is brought with the introduction of the British tutor and the green bicycle he gave the emperor as a present.
The centre of our life is represented by blue. It is the colour of freedom, perspicacity of thinking, the intellect; while red is the past and green the present, blue is the colour of the future. It is the complementary of yellow: while the latter represents the sun, blue is associated with the moon. The tone of the scenes changes into blue when the Emperor leaves the Forbidden City for the first time, exiled by communist: he always wanted to leave his "prison", his limited world but never could because they wouldn't let him. The exile is his freedom.
When Pu Yi realizes he want to be again the Emperor of China, the tone of the images becomes indigo. It is the colour associated to the age around 50. Indigo represents full maturity, material power, the achievement of a level of life, a new balance between reason and passion.
White is the sum of all the colours, therefore it is the sum of all the ages, of all the phases, feelings and passions. It is life as one, the union and the completeness of it and it is associated with the last years of life. The pure white appears for the first time with snow, when Pu Yi earns his freedom and gets out from jail as a free citizen of the People's Republic of China. He returns to the Forbidden City but this time the image is balanced, with no prevailing tone.
