Favorite City In The World

1. Tokyo

 

So much city, so little time.
Every city worth its marketing budget brands itself as “many cities in one.” Tokyo, of course, doesn’t have to.

2. Shanghai

 

Fast, furious, unforgettable -- like all the best affairs.
If there’s any proof that the world’s most alluring cities are as cyclically fashionable as Eames chairs and flapper wear, look no further than China’s commercial and financial hub. 

In the 1930s, Shanghai was the “Paris of the Orient” before succumbing to a World War and Communist revolution.

3. Santiago, Chile

 

Good times are often the simplest times.
There are bigger Carnivals and Tango festivals on the other side of the Andes, but would Buenos Aires or Rio look nearly this poised after being rocked 28 centimeters to the left by an 8.8 earthquake? 

4. San Francisco

 

World's most rickety transport system, and still adored by millions.
It’s been hailed “a golden handcuff with the key thrown away” by John Steinbeck, “one of the great cultural plateaus” by Duke Ellington and “49 square miles surrounded by reality” by Paul Kantner of Jefferson Airplane. 

5. Petra, Jordan

 

Roses are red, violets are blue, Petra you said? I'm coming too.
On August 22, 1812, a disguised, 27-year-old Swiss adventurer named Johann Ludwig Burckhardt persuaded some Bedouin tribesmen to guide him through a narrow, winding gorge in a remote corner of the Arabian Desert -- home to a rumored “lost” city of the ancient world.

6. Paris

 

A city that lives, and loves, in between its attractions.
Spoiler alert: next week, we're going to make at least 2.3 million enemies by including Paris on our Most Hated Cities list.

The thinking (corroborated by plenty of traveler feedback) is that not even Paris can live up to an unrealistic magical reputation once you’re overpaying for lukewarm coffee, staring at too many bones in the catacombs and waiting in herd-like crowds for hours just to squint at the Mona Lisa.

7. New York City

 

You profess to hate it, but inside you love it.
Paris attracts more tourists than New York. So does London, which handily beat out NYC for this summer’s Olympic bid. And Busan, South Korea now has a bigger department store than the (formerly biggest) Macy’s in Manhattan. 

Does New York care a lick? No. Why not?

Because no city is as supremely oblivious to the mere notion of also-ran status as New York -- the world’s third most-visited city on the planet according to the World Tourism Organization and the only city on the planet according to itself

8. Montreal

 

Cold? Ain't got time to feel cold.
Montreal is a frontrunner in at least one “World’s Most Livable Cities” list, was named “Canada’s Cultural Capital” by Monocle Magazine and has recently been granted UNESCO “City of Design” status.

9. Cape Town, South Africa

 

Beaches with penguins? Can't not love it.
Last November, Cape Town’s iconic peak, Table Mountain, was declared one of the 7 New Wonders of Nature in a global popularity poll, beating out places like The Grand Canyon and the Galapagos Islands.

10. Barcelona, Spain

 

Bar-celona -- where it's a good time every time.

While most old Mediterranean port cities look and act their age, Barcelona remains one of the world’s most exuberant, youthful cities -- saturated with style, cocky architecture, good eating, around-the-clock partying and unprompted comments like the following nugget from a random Catalonian shoe salesman at the Placa de Catalunya Cort Ingles department store.

Favorite Places In The World

1. New York City, USA

2. Rio de Janeiro, Brazil

 3. Phuket, Thailand

4. St. Petersburg, Russia

5. Medellin, Colombia

6. Ibiza, Spain

7. Singapore

8. Berlin, Germany

9. São Paulo, Brazil

10. Hong Kong, China

11. Sydney, Australia

12. South Beach, Miami, USA

13. Jerusalem, Israel

14. Beijing, China

15. Prague, Czech Republic

Camera Lens

A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.

There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the detailed design and construction are different. A lens may be permanently fixed to a camera, or it may be interchangeable with lenses of different focal lengths, apertures, and other properties.

While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be present in any lens system. It is the job of the lens designer to balance these out and produce a design that is suitable for photographic use and possibly mass production.

Theory of operation

Typical rectilinear lenses can be thought of as "improved" pinhole "lenses". As shown, a pinhole "lens" is simply a small aperture that blocks most rays of light, ideally selecting one ray to the object for each point on the image sensor. Pinhole lenses have a few severe limitations:

• A pinhole camera with a large aperture is blurry because each pixel is essentially the shadow of the aperture stop, so its size is no smaller than the size of the aperture (below left). Here a pixel is the area of the detector exposed to light from a point on the object.
• Making the pinhole smaller improves resolution (up to a limit), but reduces the amount of light captured.
• Diffraction limits the effectiveness of shrinking the hole, so at a point, making the hole smaller makes the image blurrier as well as darker (below center).

Practical lenses can be thought of as an answer to the question "how can we modify a pinhole lens to admit more light and give a smaller spot size?" A first step is to put a simple convex lens at the pinhole with a focal length equal to the distance to the film plane (assuming the camera will take pictures of distant objects ^[1]). This allows us to open up the pinhole significantly (below right) because a thin convex lens bends light rays in proportion to their distance to the axis of the lens, with rays striking the center of the lens passing straight through. The geometry is almost the same as with a simple pinhole lens, but rather than being illuminated by single rays of light, each image point is illuminated by a focused "pencil" of light rays.

Principle of a pinhole camera. Light rays from an object pass through a small hole to form an image.  With a large pinhole, the image spot is large, resulting in a blurry image.  With a small pinhole, light is reduced and diffraction prevents the image spot from getting arbitrarily small.  With a simple lens, much more light can be brought into sharp focus.

Standing in front of the camera, you would see the small hole, the aperture. The virtual image of the aperture as seen from the world is known as the lens's entrance pupil; ideally, all rays of light leaving a point on the object that enter the entrance pupil will be focused to the same point on the image sensor/film (provided the object point is in the field of view). If one were inside the camera, one would see the lens acting as a projector. The virtual image of the aperture from inside the camera is the lens's exit pupil. In this simple case, the aperture, entrance pupil, and exit pupil are all in the same place because the only optical element is in the plane of the aperture, but in general these three will be in different places. Practical photographic lenses include more lens elements. The additional elements allow lens designers to reduce various aberrations, but the principle of operation remains the same: pencils of rays are collected at the entrance pupil and focused down from the exit pupil onto the image plane.

Construction

Main articles: Photographic lens design and History of photographic lens design

The zoom lens assembly of the Canon Elph

A camera lens may be made from a number of elements: from one, as in the Box Brownie's meniscus lens, to over 20 in the more complex zooms. These elements may themselves comprise a group of lenses cemented together.

The front element is critical to the performance of the whole assembly. In all modern lenses the surface is coated to reduce abrasion, flare, and surface reflectance, and to adjust color balance. To minimize aberration, the curvature is usually set so that the angle of incidence and the angle of refraction are equal. In a prime lens this is easy, but in a zoom there is always a compromise.

The lens usually is focused by adjusting the distance from the lens assembly to the image plane, or by moving elements of the lens assembly. To improve performance, some lenses have a cam system that adjusts the distance between the groups as the lens is focused. Manufacturers call this different things: Nikon calls it CRC (close range correction); Canon calls it a floating system; and Hasselblad and Mamiya call it FLE (floating lens element).^[2]

Glass is the most common material used to construct lens elements, due to its good optical properties and resistance to scratching. Other materials are also used, such as quartz glass, fluorite,^[3][4][5][6] plastics like acrylic (Plexiglass), and even germanium and meteoritic glass.^[7] Plastics allow the manufacturing of strongly aspherical lens elements which are difficult or impossible to manufacture in glass, and which simplify or improve lens manufacturing and performance.^{[citation needed]} Plastics are not used for the outermost elements of all but the cheapest lenses as they scratch easily. Molded plastic lenses have been used for the cheapest disposable cameras for many years, and have acquired a bad reputation: manufacturers of quality optics tend to use euphemisms such as "optical resin". However many modern, high performance (and high priced) lenses from popular manufacturers include molded or hybrid aspherical elements, so it is not true that all lenses with plastic elements are of low photographic quality.

French brass lens for 12x12" plate camera, about 1909

The 1951 USAF resolution test chart is one way to measure the resolving power of a lens. The quality of the material, coatings, and build affect the resolution. Lens resolution is ultimately limited by diffraction, and very few photographic lenses approach this resolution. Ones that do are called "diffraction limited" and are usually extremely expensive.^[8]

Today, most lenses are multi-coated in order to minimize lens flare and other unwanted effects. Some lenses have a UV coating to keep out the ultraviolet light that could taint color. Most modern optical cements for bonding glass elements also block UV light, negating the need for a UV filter. UV photographers must go to great lengths to find lenses with no cement or coatings.

A lens will most often have an aperture adjustment mechanism, usually an iris diaphragm, to regulate the amount of light that passes. In early camera models a rotating plate or slider with different sized holes was used. These Waterhouse stops may still be found on modern, specialized lenses. A shutter, to regulate the time during which light may pass, may be incorporated within the lens assembly (for better quality imagery), within the camera, or even, rarely, in front of the lens. Some cameras with leaf shutters in the lens omit the aperture, and the shutter does double duty.

Aperture and focal length

Large (top) and small (bottom) apertures on the same lens.

How focal length affects photograph composition: adjusting the camera's distance from the main subject while changing focal length, the main subject can remain the same size, while the other at a different distance changes size.

The two fundamental parameters of an optical lens are the focal length and the maximum aperture. The lens' focal length determines the magnification of the image projected onto the image plane, and the aperture the light intensity of that image. For a given photographic system the focal length determines the angle of view, short focal lengths giving a wider field of view than longer focal length lenses. A wider aperture, identified by a smaller f-number, 

allows using a faster shutter speed for the same exposure.^[9]

The maximum usable aperture of a lens is specified as the focal ratio or f-number, defined as the lens' focal length divided by the effective aperture (or entrance pupil), a dimensionless number. The lower the f-number, the higher light intensity at the focal plane. Larger apertures (smaller f-numbers) provide a much shallower depth of field than smaller apertures, other conditions being equal. Practical lens assemblies may also contain mechanisms to deal with measuring light, secondary apertures for flare reduction,^[10] and mechanisms to hold the aperture open until the instant of exposure to allow SLR cameras to focus with a brighter image with shallower depth of field, theoretically allowing better focus accuracy.

Focal lengths are usually specified in millimetres (mm), but older lenses might be marked in centimetres (cm) or inches. For a given film or sensor size, specified by the length of the diagonal, a lens may be classified as a:

• Normal lens: angle of view of the diagonal about 50° and a focal length approximately equal to the image diagonal.
• Wide-angle lens: angle of view wider than 60° and focal length shorter than normal.
• Long-focus lens: any lens with a focal length longer than the diagonal measure of the film or sensor.^[11] Angle of view is narrower. The most common type of long-focus lens is the telephoto lens, a design that uses special optical configurations to make the lens shorter than its focal length.

A side effect of using lenses of different focal lengths is the different distances from which a subject can be framed, resulting in a different perspective. Photographs can be taken of a person stretching out a hand with a wideangle, a normal lens, and a telephoto, which contain exactly the same image size by changing the distance from the subject. But the perspective will be different. With the wideangle, the hands will be exaggeratedly large relative to the head. As the focal length increases, the emphasis on the outstretched hand decreases. However, if pictures are taken from the same distance, and enlarged and cropped to contain the same view, the pictures will have identical perspective. A moderate long-focus (telephoto) lens is often recommended for portraiture because the perspective corresponding to the longer shooting distance is considered to look more flattering.

The widest aperture lens in history of photography is believed to be the Carl Zeiss Planar 50mm f/0.7,^[12] which was designed and made specifically for the NASA Apollo lunar program to capture the far side of the moon in 1966. Three of these lenses were purchased by filmmaker Stanley Kubrick in order to film scenes in his movie Barry Lyndon, using candlelight as the sole light source.^[13][14][15]

An example of how lens choice affects angle of view. The photos were taken by a 35 mm camera at a constant distance from the subject.

28 mm lens  50 mm lens  70 mm lens  210 mm lens

Number of elements

Main article: Photographic lens design

Distinct reflections are visible from the surfaces of different lens elements in this 45mm f/2 MD-Rokkor lens. The lens contains 6 elements in 5 groups.

The complexity of a lens — the number of elements and their degree of asphericity — depends upon the angle of view, the maximum aperture, and intended price point, among other variables. An extreme wideangle lens of large aperture must be of very complex construction to correct for optical aberrations, which are worse at the edge of the field and when the edge of a large lens is used for image-forming. A long-focus lens of small aperture can be of very simple construction to attain comparable image quality: a doublet (two elements) will often suffice. Some older cameras were fitted with "convertible" lenses of normal focal length. The front element could be unscrewed, leaving a lens of twice the focal length, and half the angle of view and half the aperture. The simpler half-lens was of adequate quality for the narrow angle of view and small relative aperture. Obviously the bellows had to extend to twice the normal length.

Good-quality lenses with maximum aperture no greater than f/2.8 and fixed, normal, focal length need at least three (triplet) or four elements (the trade name "Tessar" derives from the Greek tessera, meaning "four"). The widest-range zooms often have fifteen or more. The reflection of light at each of the many interfaces between different optical media (air, glass, plastic) seriously degraded the contrast and color saturation of early lenses, particularly zoom lenses, especially where the lens was directly illuminated by a light source. The introduction many years ago of optical coatings, and advances in coating technology over the years, have resulted in major improvements, and modern high-quality zoom lenses give images of quite acceptable contrast, although zoom lenses with many elements will transmit less light than lenses made with fewer elements (all other factors such as aperture, focal length, and coatings being equal).^[16]

Lens mounts

Main article: Lens mount

Many Single-lens reflex cameras, and some rangefinder cameras have detachable lenses. A few other types do as well, notably the Mamiya TLR cameras and mirrorless interchangeable-lens cameras. The lenses attach to the camera using a lens mount, which contains mechanical linkages and, often also electrical contacts between the lens and camera body.

The lens mount design is an important issue for compatibility between cameras and lenses. There is no universal standard for lens mounts, and each major camera maker typically uses its own proprietary design, incompatible with other makers.^[17] A few older manual focus lens mount designs, such as the Leica M39 lens mount for rangefinders, M42 lens mount for early SLRs, and the Pentax K mount are found across multiple brands, but this is not common today. A few mount designs, such as the Olympus/Kodak Four Thirds System mount for DSLRs, have also been licensed to other makers.^[18] Most large-format cameras take interchangeable lenses as well, which are usually mounted in a lensboard or on the front standard.

The most common interchangeable lens mounts on the market today include the Canon EF, EF-S and EF-M autofocus lens mounts, the Nikon F manual and autofocus mounts, the Olympus/Kodak Four Thirds and Olympus/Panasonic Micro Four Thirds digital-only mounts, the Pentax K mount and autofocus variants, the Sony Alpha mount (derived from the Minolta mount) and the Sony E digital-only mount.

Types of lens

"Close-up" or macro

A macro lens used in macro or "close-up" photography (not to be confused with the compositional term close up) is any lens that produces an image on the focal plane (i.e., film or a digital sensor) that is the same size or larger than the subject being imaged. This configuration is generally used to image close-up very small subjects. A macro lens may be of any focal length, the actual focus length being determined by its practical use, considering magnification, the required ratio, access to the subject, and illumination considerations. They can be special lens corrected optically for close up work or they can be any lens modified (with adapters or spacers) to bring the focal plane "forward" for very close photography. The depth-of-field is very narrow, limiting their usefulness. Lenses are usually stopped down to give a greater depth-of-field.^[9][19]

Zoom

Main article: Zoom lens

Some lenses, called zoom lenses, have a focal length that varies as internal elements are moved, typically by rotating the barrel or pressing a button which activates an electric motor. Commonly, the lens may zoom from moderate wide-angle, through normal, to moderate telephoto; or from normal to extreme telephoto. The zoom range is limited by manufacturing constraints; the ideal of a lens of large maximum aperture which will zoom from extreme wideangle to extreme telephoto is not attainable. Zoom lenses are widely used for small-format cameras of all types: still and cine cameras with fixed or interchangeable lenses. Bulk and price limit their use for larger film sizes. Motorized zoom lenses may also have the focus, iris, and other functions motorized.

Special-purpose

Instant Camera

The instant camera is a type of camera that generates a developed film image. The most popular types to use self-developing film were formerly made by Polaroid Corporation.

The invention of modern instant cameras is generally credited to American scientist Edwin Land, who unveiled the first commercial instant camera, the Land Camera, in 1948, a year after unveiling instant film in New York City. The earliest instant camera, which consisted of a camera and portable darkroom in a single compartment, was invented in 1923 by Samuel Shlafrock.

In February 2008, Polaroid announced it would discontinue production of film, shut down three factories and lay off 450 workers. Sales of chemical film by all makers have dropped by at least 25% per year in the first decade of the 21st century. Fujifilm is now the only remaining supplier of instant film in the United States. However, in October 2009, Polaroid announced it would bring back its classic instant film cameras, after announcing the year before that production was to be stopped.

Types of Polaroid instant cameras

Polaroid cameras can be classified by the type of film they use. The earliest Polaroids (pre-1963) used instant roll film, which has since been discontinued. Roll film came in two rolls (positive/developing agent and negative) which were loaded into the camera and eventually offered in three sizes (40, 30, and 20 series). Later cameras utilized "pack film," which required the photographer to pull the film out of the camera for development, then peel apart the positive from the negative at the end of the developing process. Pack film initially was offered in a rectangular format (100 series), then in square format (80 series). Later Polaroids, like the once popular SX-70, used a square format integral film, in which all components of the film (negative, developer, fixer, etc.) were contained. Each exposure developed automatically once the shot is taken. SX-70 (or Time Zero) film was recently discontinued but had a strong following from artists who used it for image manipulation.

600 series cameras such as the Pronto, Sun 600, and One600 use 600 (or the more difficult to find professional 779) film. Polaroid Spectra cameras use Polaroid Spectra film which went back to a rectangular format. Captiva, Joycam, and Popshots (single use) cameras use a smaller 500 series film in rectangular format. I-zone cameras use a very small film format which was offered in a sticker format. Finally, Mio cameras used Mio film, which was a film format smaller than 600, but larger than 500 series film.

Instant movie cameras

Main article: Polavision

Not only did Polaroid make instant still-image cameras, but they also manufactured a type of instant movie camera. The unit was called Polavision. The kit included a camera, film, and a movie viewer. When the movie was shot, it would be taken out of the camera and then inserted into the viewer for development, then viewed after development. This format was close to Super 8 mm film. Polavision film was different from normal film in that it was an additive film, mixing the primary colors (red, green, blue) to form the color image. The biggest disadvantage of the Polavision system was the low film speed (ASA 40), which resulted in having to use very bright lights when taking the movie, as well as requiring a special player to view the developed movie. Because of this, and combined with the advent of VHS video recorders, Polavision had a short history.

Types of non-Polaroid instant cameras

Kodak EK6 Instant Camera

The earliest instant cameras were conceived before Edwin Land's invention of the instant camera. These cameras are, however, more portable darkrooms than "instant" camera and were difficult to use. After Land's instant camera invention was brought to market in 1948, a few different instant cameras were developed, some using Polaroid-compatible film such as cameras by Keystone, Konica, and Minolta. Others were incompatible with Polaroid cameras and film, the most notable of these being made by Kodak, such as the EK series and Kodamatic cameras. These cameras accepted a Kodak developed integral instant film, similar to Polaroid's SX-70 film. Kodak instant film was chemically similar to Polaroid with the exception that the negative was exposed from the rear and the dye/developers diffused to the front of the photogragh. This alleviated the need for a mirror to reverse the image before it struck the negative. Even so, Polaroid brought a patent-infringement lawsuit against Kodak, and eventually Kodak was forced to stop manufacture of both the camera and film. Kodak was also left to pay a settlement to customers who were left without a way to use their now defunct cameras. One settlement offered owners of Kodak instant cameras a credit towards a new Kodak camera. Many still exist and can be found on auction sites. Kodak also lost the contract to manufacture Polaroid's negatives which subsequently took production in house.

Fujifilm Instax 500AF camera

Fujifilm Instax Mini 25 camera

In more recent years, Fujifilm has introduced a line of instant cameras and film in Japanese and Asian markets. Fujifilm called their instant camera line Fotorama. Starting in the early 1980s the F series of cameras include the F-10, F-50S and F-62AF. The mid '80s introduced the 800 series with models such as the MX800, 850E, and Mr Handy collapsible. The ACE cameras were introduced in the mid-1990s and film identical to the 800 film but with different cartridge. The integral films are based on the Kodak line of instant camera films. The instant films FI-10/PI-800/ACE series are somewhat compatible with Kodak line of instant cameras, with minor modifications to the cartridge to make it fit. The F series film was discontinued in 1994 but similar modifications on other Fujifilm cartridge box can be made. In the late 1990s Fujifilm introduced a new series of cameras using a new film called Instax it was available in markets outside the US. Instax became available in smaller mini size with the introduction of the Instax mini/Cheki line. The Polaroid's Mio was available in the US, it uses the same film as the Fujifilm Instax Mini series but were rebranded as Mio film. None of Fujifilm's products were sold officially in the United States, although the Polaroid-compatible film is available through some larger photographic suppliers. With the announcement in 2008 of Polaroid ceasing film production, the Instax and peel apart type films are slowly becoming available in more channels.

Usage

Instant cameras have found many uses throughout their history. The original purpose of instant cameras was motivated by Jennifer Land's question to her father (Edwin Land): "Why can't I see them now?" Many people have enjoyed seeing their photos shortly after taking them, allowing them to recompose or retake the photo if they didn't get it right. But instant cameras were found to be useful for other purposes such as ID cards, passport photos, ultrasound photos, and other uses which required an instant photo. They were also used by police officers and fire investigators because of their ability to create an unalterable instant photo. Medium and large format professional photographers have also used the higher end instant cameras to preview lighting before taking the more expensive medium and/or large format photo. Instant film also has been used in ways that are similar to folk art, including the transfer of the images/emulsion and image manipulation. Script supervisors in film production used polaroid cameras as standard to aid visual continuity by photographing characters or sets, producing photographs that could be instantly referred to when a particular set or character's appearance needs to be reset and shot again, or recalled later due to the non linear shooting schedule of a film or television production (that is, a film is rarely shot in the order of chronology in the film, due to time, location or financial restraints). Script supervisors no longer use polaroid cameras due to digital technology. With the advent of digital photography, much of the instant camera's consumer appeal has been transferred to the digital cameras. Even most passport photo cameras have gone to digital, leaving instant cameras to a niche market.

Taking an instant photograph

Edwin Land's original idea behind instant photography was to create a photographic system that was seamless and easy for anyone to use. The first roll film cameras required the photographer to use a light meter to take a reading of the light level, then to set the exposure setting on the lens. Then the lens was focused and the subject framed and the picture was taken, the photographer flipped a switch and pulled the large tab in the back of the camera to pull the negative over the positive, through some rollers to spread the developing agent. After the picture developed inside the camera for the required time, the photographer opened the small door in the camera back and peeled the positive from the negative. To prevent fading the black and white positive had to be coated with a fixing agent, a potentially messy procedure which led to the development of coaterless instant pack film.

Pack film cameras operated in a similar manner except for the fact that most of these cameras had automatic exposure. The development of the film required the photographer pull two tabs, the second tab which pulled the positive/negative "sandwich" from the camera, where it developed outside the camera. If the temperature was below 60°F, the positive/negative "sandwich" was placed between two aluminum plates and placed either in the user's pocket or under their arm to keep it warm while developing. After the required development time (15 seconds to 2 minutes), the positive was peeled apart from the negative.

Integral film cameras, such as the SX-70, 600 series, Spectra, and Captiva cameras went a long way in accomplishing Edwin Land's goal of creating a seamless process in producing instant photos. The photographer simply pointed the camera at the subject, framed it, and took the photo. The camera and film did the rest, including adjusting the exposure settings, taking care of focusing (Sonar autofocus models only), utilising a flash if necessary (600 series and up), and ejecting the film, which developed without intervention from the photographer.