Exposure Understanding Exposure – ISO, Aperture and Shutter Speed Explained

Exposure

Understanding Exposure – ISO, Aperture and Shutter Speed Explained

When you think of the craft or art of photography, you must immediately think of exposure. Exposure is a critical element that determines what is actually recorded on film or the image sensor. There are three adjustable elements that control the exposure – ISO, Aperture and Shutter Speed.

1

What controls exposure?

ISO ratings determine the image sensor’s sensitivity to light, each value of the rating represents a “stop” of light, and each incremental ISO number (up or down) represents a doubling or halving of the sensor’s sensitivity to light.

The Aperture controls the lens’ diaphragm, which controls the amount of light traveling through the lens to the film plane. The aperture setting is indicated by the f-number, whereas each f-number represents a “stop” of light.

The Shutter Speed indicates the speed in which the curtain opens then closes, and each shutter speed value also represents a “stop” of light. The shutter speed is measured in fractions of a second.

The Exposure Triangle

When these three elements are combined, they represent a given exposure value (EV) for a given setting. Any change in any one of the three elements will have a measurable and specific impact on how the remaining two elements react to expose the film frame or image sensor and how the image ultimately looks. For example, if you increase the f-stop, you decrease the size of the lens’ diaphragm thus reducing the amount of light hitting the image sensor, but also increasing the DOF (depth of field) in the final image. Reducing the shutter speed affects how motion is captured, in that this can cause the background or subject to become blurry. However, reducing shutter speed (keeping the shutter open longer) also increases the amount of light hitting the image sensor, so everything is brighter. Increasing the ISO, allows for shooting in lower light situations, but you increase the amount of digital noise inherent in the photo. It is impossible to make an independent change in one of the elements and not obtain an opposite effect in how the other elements affect the image, and ultimately change the EV.

I

ISO Speed

ISO Sensitivity

ISO is actually an acronym, which stands for International Standards Organization. The ISO rating, which ranges in value from 25 to 3200 (or beyond), indicates the specific light sensitivity. The lower the ISO rating, the less sensitive the image sensor is and therefore the smoother the image, because there is less digital noise in the image. The higher the ISO rating (more sensitive) the stronger the image sensor has to work to establish an effective image, which thereby produces more digital noise (those multi-colored speckles in the shadows and in the midtones). So what is digital noise? It is any light signal that does not originate from the subject, and therefore creates random color in an image. The digital camera engineers have designed the image sensor to perform best at the lowest ISO (just like with film). On most digital cameras this is ISO 100, although some high end DSLRs have a mode that brings the ISO down to 50 or even 25.

A

Aperture

Large vs. Small Aperture

A lens’s aperture is the opening in the diaphragm that determines the amount of focused light passing through the lens. At a small f-stop, say f/2, a tremendous amount of light passes through, even at a fraction of a second; but at f/22, when the diaphragm is perhaps at its smallest, only a tiny amount of light is let in (even at longer shutter speeds). An interesting thing about the aperture and the f-numbers is that it doesn’t matter the focal length of the lens as long as the f-number is held constant. This is because the arithmetical equation that determines the f-number indicates that the same amount of light passes through the lens on a 35mm lens as on a 100mm lens, with a shutter speed of 1/125s. The size of the diaphragm is unquestionably different, but the amount of light passing through is the same.

S

Shutter Speed

Shutter Speed Comparison

Shutter speed is measured in fractions of a second, and indicates how fast the curtains at the film plane open and close. The shutter speed controls how long light enters the lens and hits the image sensor or film plane. The shutter speed enables you to capture the world in split seconds, but it can also absorb the world at speeds upwards of three and four seconds (or remain continually open up until the photographer wants to close the curtain). Snapping the shutter in a fraction of a second, also gives you control on how motion is recorded. If the shutter speed is faster than the object or background, then the image will be tack sharp. If the shutter speed is slower, then you’ll get blurred objects. Think about the rain in a rainstorm, how fast is that water falling? Well, at 1/30th the raindrops are streaks of undistinguishable white. But at 1/250th, the raindrops hover in mid air and you can see the full swell of each water drop.

2

What is “Auto Bracketing”?

Auto Bracketing

Auto Bracketing is an exposure technique whereby you can ensure that you have the optimal exposure by taking at least three (3) exposures of the exact same composition with one at the metered EV, one at 1/3 of a stop below the metered EV and one at 1/3 of a stop above the metered EV. So “Auto Bracketing” is a function in which you set the EV value then release the shutter and the camera automatically makes the necessary up and down adjustments to the EV to give you the bracketed exposures. Then you can review the three (or more) exposures, see the subtle but critical differences in the images, and decide which one is the best image for your purposes. In the three images on the right, you might prefer the overexposed (by 2 stops) image because the setting sun is most brilliant. Bracketing was a technique that was popularized from shooting slide film, due to the limited ability to correct the image in the darkroom. Many photographers still use the technique today, so they have the exposure that they want. Having the three bracketed images lowers the amount of post-processing time that they might have to spend.

3

Overexposure & Underexposure

Exposure Comparison, Overexposure to Underexposure

How do you define overexposure and underexposure, since we said that “correct” exposure is subjective? Simply put, overexposure is when the information in the highlights is effectively unreadable. When there is this type of excessive loss of image information there is no way to “retrieve” that missing information in the digital dark room. Underexposure is pretty much the same concept; except in this case there is no image information contained within the shadows. This non-existant information cannot be retrieved through post processing either. In digital photography, once that image information is gone, there’s no way to retrieve it. This is not always the case in the photochemical world of film photography. With film (as opposed to digital) processing, it is possible to “find” image information in an excessively underexposed frame, and perhaps “find” image information during the printing process for seriously overexposed images as well.

4

AE LOCK (AEL)

Auto Exposure Lock is a camera setting in which the EV is locked in (when you’re shooting one of the semi-automatic or fully automatic modes, i.e. Shutter-priority), so that now matter what changes there are to the lighting in the scene, the camera locks in the ISO, Shutter and/or Aperture settings, so you can continually achieve the same EV without having to re-meter the scene.

C

Conclusion

One highly practical advantage to digital photography is that it costs next to nothing to experiment with the camera’s controls, so go out there and shoot away. You want to become increasingly proficient with all three elements of the exposure triangle, so that you can make adjustments on the fly and know exactly what the resulting effect is going to be.

Tomado de:

http://www.exposureguide.com/exposure.htm

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Las fotos detrás de grandes películas

Breathtaking Multicolored Infrared Landscapes

Breathtaking Multicolored Infrared Landscapes


Thanks to the color-altering technology known as infrared, we’ve seen the war-torn Congo as a vibrant pink escape and the city of Kiev transformed into an icy winter wonderland. There’s something about infrared photography that is endlessly captivating and France-based photographer David Keochkerian’s Infrared series is no exception. Rather than sticking to one color scheme, Keochkerian’s collection of fascinating shots depicts several landscapes in an almost alien variety of color combinations.

The natural greens found in any given verdant landscape is automatically revamped as golden yellows, frosty whites, sapphire blues, and radiant pinks. The sky and water is also given the infrared makeover, complementing the setting’s new eye-popping color palette. The juxtaposition of blue blades of grass against an orange sky is an unnatural yet eye-catching occurrence. More than just the color changes of the seasons, Keochkerian’s captured landscapes are like something straight out of a science fiction novel.












David Keochkerian website
David Keochkerian on 500px
via [Gaks]

Tomado de:

http://www.mymodernmet.com/profiles/blogs/david-keochkerian-infrared

Que hacemos? Que cargamos?

Eco Mensajeria / 1er colectivo de mensajeros en bici en la isla PR

Que cargamos? 2

Que cargamos? 1

Somos los pioneros en Puerto Rico de la mensajería en bicicleta desde mayo del 2011. Que hacemos? Que cargamos? De todo! Cartas, cajas, documentos legales, radicaciones, comida, pagos, depósitos, ropa a la lavandería. invitaciones, regalos, flores, periódicos, comida de perro, posters, etc.

Ver la entrada original

How to Take Beautiful Bokeh Christmas Images [With 39 Stunning Examples]

How to Take Beautiful Bokeh Christmas Images [With 39 Stunning Examples]

by Darren Rowse

LOVE 10/50

It’s beginning to feel a lot like Christmas… and in our forums I’ve noticed more and more great Christmas images being shared – some of which feature a technique that is always popular at this time of year – Bokeh Christmas lights shots.

Christmas tree lights II

The technique takes a bit of experimenting and practice but is relatively simple to do. You need some Christmas lights and a camera lens with a reasonably ‘fast’ aperture (or a large aperture).

#ds385 - Red Wool Socks

The key is to shoot at the larger end of your available aperture – this throws the background (and foreground) of your shot out of focus and any Christmas lights in the foreground or background will become little balls of light.

Dreaming about bokeh

As you’ll see in most of the images featured in this series – the technique is particularly good if you also have some element in your shot that is in focus. This ‘subject’ might be a person, a pet, a Christmas decoration or something else.

Gracie

You can make the little balls of light bigger by increasing the distance between your in focus subject and the out of focus lights in the background.

Holiday bokeh

While most of the images in this series have the Christmas lights in the background of the image (behind the subject) it is also possible to create the little bokeh balls of light by putting the lights in the foreground of your image (in front of your subject). You can see this in the image below. The impact is a little different as the bokeh balls will cover part of your subject.

335/365: ¿Que puedo hacer con estas luces que no se haya hecho ya?

Another popular technique is to create different shaped bokeh. You can make stars, hearts or even little snow flakes like the image below.

Joyeux Noël!  Merry Christmas!

To get these different little bokeh shapes is pretty simple. You just need to make a little cutout ‘mask’ for your lens. Rather than go over how to do it here check out this video tutorial that will walk you through it here.

My Cat's Starry Christmas

Love a Good Buzz - 347/365

The other way to change the shape of your bokeh balls is to experiment with different apertures. You’ll find that in most cases the larger your aperture the rounder the ball – but go for a slightly smaller aperture you may find your bokeh becomes more hexagonal (or Heptagonal or Octagonal… the number of sides will depend upon how many blades your lens has).

christmas kiss

The different ways of using this bokeh Christmas lights technique is only limited by your imagination. Here are some more examples to give you ideas. Enjoy!

Letters to Santa

Christmas Ball-keh (Explored!)

bright lights

Day 4 - 25 Days of Christmas 2007

Brighton Clock Tower

magic of the season

love

Light way

lick

Seasons Greetings - Explore 28.12.09

Happy Holidays!

Merry Christmas to all my Flickr friends.

Blurry Christmas....

What to my wondering eyes should appear ...

Have a Very Bokeh Christmas

Warm Fuzzies

Elvis!

HAPPY CHRISTMAS BOKEH! XXX WWW.SIMONKEEPING.CO.UK

Christmas lights bokeh

2007-0001-0016

Boy Christmas I

Mireia

50mm Noctilux-M f/1.0

Christmas Lights Bokeh Baby

Merry Christmas

Bokeh Hostage + 65/365

...and to all a good night!

Falling Stars (EXPLORE #18)

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Read more: http://digital-photography-school.com/how-to-take-beautiful-bokeh-christmas-images-with-31-stunning-examples#ixzz2EhaWOKkt

Eliminate Oversharpening

Eliminate Oversharpening

Get the benefits of creative sharpening without the drawbacks

By William Sawalich

 

Digital Photo Tip Of The Week

Sharpening is one of the most- un-glamorous, yet totally essential, digital imaging edits you can make to your photographs. Sharpening is a must if you want to make your images look their best; RAW files require sharpening to make them look like JPEGs, and JPEGs (as well as RAW, TIFFs and every other image file format) require specific sharpening based on the output of the finished image. Not to mention the creative sharpening that dramatically affects the style of a photograph, which is all subjective based on creative license

But this post isn’t about how to sharpen. It’s about the downside of sharpening—the artifacts and problems that you can create in your digital image files by sharpening too much. So keep reading to find out how to minimize sharpening problems and keep from oversharpening in the first place.

The best way to eliminate sharpening artifacts is to keep from oversharpening in the first place. How do you do this? You sharpen deliberately. The Threshold slider in Photoshop’s Unsharp Mask filter (a favorite sharpening tool for many photographers, myself included) is a powerful tool. With it you can dictate what types of edges are sharpened in a photograph. To understand this fully, I’ll back up for a second and explain how sharpening works.

Digital Photo Tip Of The Week

Digital image sharpening is essentially a function of accentuating the contrast between edges of light and dark within a scene. A portrait subject’s dark shoulder against a light background, for instance, is an example of a large edge that can be accentuated (or artificially “sharpened”) in a digital image. But so is the contrast edge between a highlight in the eye and the dark part of the iris, and the edge between a hair and skin, and the edge between a pore’s highlight and shadow. All of those edges of contrast can be sharpened, so it’s up to you to dictate which ones and how much. That brings us back to Threshold.

The Amount and Radius controls in sharpening tools like Unsharp Mask dictate, as you can tell, the amount of sharpening and the radius (measured in pixels from the contrast edge) of the affect. But it’s the Threshold that determines which edges will be affected. A higher threshold limits sharpening to the biggest, boldest edges in a scene (like shoulders in a portrait), whereas a lower threshold allows every edge to be affected—including all those hairs and pores. The problem this illustrates is the added sharpness in things like pores and hairs (not to mention blemishes and flaws) is almost never desirable. The faux sharpness exaggerates problems and creates one type of sharpening artifact: the added appearance of noise-like texture that comes from giving more pixels more defined edges. To eliminate this, start with a higher threshold and lessen the amount of the sharpening. Concentrate on sharpening more significant contrast edges to minimize this grainy, noisy, hypertextured variety of oversharpening.

Digital Photo Tip Of The Week

The other telltale sign of oversharpening is a halo effect around major contrast edges. This appears most often as a dark shadowed outline that spills into bright areas, and it can be very distracting. To eliminate it, of course you could start by sharpening a lesser amount, or adjusting the Radius to be slightly smaller, but this type of sharpening artifact is usually a side effect from creative sharpening that is desirable elsewhere in the frame. I find it happens a lot when I’m fairly aggressive with the Clarity slider in Lightroom; it crops up if I’m really accentuating the sharpness of a scene to give it an edgier look. But I want to eliminate this telltale sign of oversharpening without eliminating the rest of the “good” sharpness in the scene. To do that in Lightroom I use the Adjustment Brush in the Develop module and adjust the clarity slider way down toward -100. Then I simply paint away the oversharpened halo wherever it’s evident in the frame. In Photoshop, a simple layer mask on the oversharpened layer allows you to selectively paint away artifacts. This level of selective control, whether you wield it in Photoshop or Lightroom, is a great way to get the benefits of dynamic sharpening without the drawbacks.

Tomado de http://www.dpmag.com/how-to/tip-of-the-week/eliminate-oversharpening-12-3-12.html?utm_source=newslettertotw&utm_medium=email&utm_campaign=DPTOTWeNews_120512

Cámaras Lomo: ¿las salvadoras de la fotografía analógica?

Cámaras Lomo: ¿las salvadoras de la fotografía analógica?

Stephen Dowling

BBC

 Sábado, 1 de diciembre de 2012
Cámara Lomo

La fotografía analógica o química vivió tiempos de angustia cuando las cámaras digitales salieron al mercado en la década de los 90. Entonces, parecía que desaparecerían por completo.

Sin embargo, con la ayuda de Vladimir Putin -entonces vicealcalde de San Petersburgo- la pequeña cámara Lomo se convirtió en un clásico retro de culto y demostró que la película aún ofrecía un futuro brillante.

En 1991, un grupo de estudiantes de arte de Austria realizaron un viaje a la cercana ciudad de Praga, en la República Checa, y encontraron una curiosa cámara en una tienda de fotografía.

Negra, compacta y pesada, se trataba de un equipo rudimentario. La lente estaba protegida por una tapa deslizante. Tanto la carga de la película, como el enfoque y el rebobinado debían realizarse manualmente.

Después de efectuar el primer disparo, los estudiantes descubrieron que la cámara realizaba imágenes muy distintas a cualquier otras que hubieran visto antes.

El Instragram análogo

Características únicas

  • Viñetas: las fotografías hechas con una Lomo muestran una viñeta característica en los bordes.
  • Colores vivos: un sello Lomo, especialmente si la película se revela con procesos químicos específicos.
  • Velocidad de obturación larga: el obturador de la Lomo LC-A se mantiene abierto durante el tiempo necesario para exponer una foto, que puede dar lugar a interesantes senderos de luz.
  • Película caducada: el lente de la LC-A se adapta a los cambios deformados de color de una película barata y vencida.
  • Pequeño tamaño: la mejor cámara es la que se lleva siempre y la LC-A cabe en el bolsillo de la chaqueta.

Los colores eran ricos y saturados, un efecto acentuado por la tendencia de la lente a oscurecer las esquinas del marco y crear un efecto de viñeteado similar a un túnel. Había dramáticos contrastes entre la luz y la oscuridad.

Los austriacos se engancharon y sus amigos hicieron lo mismo cuando les mostraron los resultados, de vuelta a casa en Viena.

La pequeña cámara era la LOMO LC-A, construida en la era soviética por la Unión de Ópticos y Mecánicos de Leningrado (LOMO, por sus siglas en ruso). Muy pronto la locura había comenzado. La Lomo se convirtió en el Instagram análogo durante los días previos a la fotografía digital.

Esta moda podría haber ayudado a resguardar la fotografía análoga, salvándola de un final prematuro.

En 1992, los estudiantes crearon la Sociedad Lomográfica Internacional y mostraron fotos tomadas con Lomos que habían sido compradas en todas partes de Europa.

Luego, a mediados de los años 90, después de que se agotara el inventario de Lomos que estuvieron acumulando polvo en Budapest, Bucarest y Berlín Oriental durante años, acudieron en la búsqueda de los fabricantes de la cámara -que seguían en San Petersburgo- y los persuadieron para reiniciar la producción. Esas negociaciones lograron concretarse gracias al apoyo de Putin.

Este 23 de noviembre, la lomografía celebró su 20 aniversario con una serie de fiestas en algunas de sus 36 tiendas de todo el mundo.

Fotografía tomada con una Lomo

La lomografía

El movimiento de arte está definido por las 10 reglas de oro de la lomografía, que ponen énfasis en la espontaneidad, la experimentación y el rechazo de algunas de las leyes básicas de composición y enfoque de la fotografía. Es común que los lomógrafos intervengan los negativos con productos químicos para añadir un estímulo adicional a los colores y al contraste, y también para jugar con filtros de color.

La original LC-A ahora forma parte de una serie de cámaras por el estilo. Aunque algunas son rediseños de la LC-A, también hay varios modelos de “juguete” con lentes de plástico, como la Sprocket Rocket, que expone la marca de los agujeros del carrete de la película en la fotografía, y la Spinner, que gira al efectuar el disparo y logra capturar imágenes de 360 grados. La adición más reciente es una retro de mediano formato conocida como Belair.

Como la gama de películas de los gigantes Kodak y Agfa ha disminuido, la lomografía también ha rescatado las viejas emulsiones que se encontraban en extinción e incluso ha creado nuevas. Se ha especulado acerca de que podría comprar los derechos de algunas de las fórmulas de Kodak, ya extinguidas, si el gigante -ahora en bancarrota- llega a vender su división de rollos (películas) de fotografía.

“El mundo que nos rodea no está retocado y a todos nos haría bien maravillarnos con las peculiaridades de las escenas cotidianas y la avistamientos casuales”

Toby Mason, fotógrafo británico

Toby Mason, fotógrafo de la ciudad de Brighton en Reino Unido, dice que las debilidades de la lomografía -las cosas que los fotógrafos convencionales podrían considerar aberraciones- son las que la vuelven atractiva. En su opinión, la fotografía se convierte con demasiada frecuencia en una búsqueda estéril y técnica.

“No puedo dejar de pensar en que el énfasis se pone más en la calidad (y el costo) de los equipos, el zoom y la capacidad del fotógrafo para manipular una imagen en Photoshop o Lightroom, que en el acto de tomar fotografías que evoquen un sentimiento “, dice.

“El mundo que nos rodea no está retocado y a todos nos haría bien maravillarnos con las peculiaridades de las escenas cotidianas y la avistamientos casuales. Me gusta usar película porque siento que le otorgan más carácter a las fotografías, de la misma manera que la música en vinilo no es tan “perfecta” como la digital en un CD. Está claro que tiene más alma”.

Encanto

El fotógrafo Kevin Meredith se sintió atraído por la LC-A porque quería una cámara que cupiera en el bolsillo “y tomara fotos decentes por la noche”.

Él compró su primera cámara Lomo a finales de los 90, antes de que las cámaras digitales compactas salieran al mercado. “Una 35 mm decente podía costar US$470, de modo que pagar $140 por LC-A era una baratija”.

Fotografía tomada con una Lomo

Su afinidad con la Lomo dio un impulso a su carrera como profesor y escritor.

“Me desarrollé como fotógrafo porque tenía esta pequeña cámara conmigo todo el tiempo, lo que significa que nunca perdí una oportunidad de foto. Luego, al revelarlas, utilizaba procesos químicos que conseguían que las imágenes tuvieran un toque único y se destacaran entre la multitud”.

El auge de la fotografía digital ha provocado que la fotografía analógica se vuelva redundante. En lugar de tener que esperar para revelar los rollos de película, los fotógrafos digitales ahora pueden revisar y modificar sus fotos al instante. Las cámaras Lomo también han sido ridiculizadas por algunos como un accesorio de moda, que es comprado por la gente que está más preocupada por las tendencias que por el amor al arte de la fotografía.

Pero la lomografía también tiene entre sus fanáticos a distintas celebridades como el protagonista de la película “El Señor de los Anillos”, Elijah Wood, hasta la banda de rock The White Stripes.

Las reglas de oro

Cámara Lomo

  1. Lleve su cámara a dondequiera que vaya.
  2. Úsela en cualquier momento del día o la noche.
  3. La lomografía no es una interferencia en su vida, es parte de ella.
  4. Intente disparar desde su cadera.
  5. Acérquese a los objetos de su deseo lomográfico lo más cerca posible.
  6. No piense.
  7. Sea rápido.
  8. No tiene que saber de antemano lo que capturó en la película….
  9. …ni tampoco después de haber apretado el obturador.
  10. No se preocupe por las reglas.

Incluso ha logrado colarse en la fotografía de boda. La británica Emma Case utiliza cámaras de este tipo -incluso de juguete- para retratar este tipo de conmemoraciones.

“Aunque principalmente utilizo una cámara digital en las bodas, también tengo cámaras lomográficas que acostumbro a usar en ciertos momentos del día. Tiendo a usar mi Diana (con lente de plástico), mi LCA+ y mi Polaroid, para obtener piezas más creativas. En los retratos de parejas, por ejemplo, se puede tener más tiempo para jugar o encontrar la luz adecuada”.

Los devotos de la lomografía parecen despreocupados por el surgimiento de imitadores digitales de Lomos, como Instagram o Hipstamatic.

“Cuando todo nuestro alrededor está buscando una solución y resultados inmediatos e imágenes que se pueden tomar, ver y borrar en un instante, queda claro que la lomografía está haciendo algo grande por ir contra la corriente”, dice Mason.

Y es que también existe un tipo de emoción que los fotógrafos digitales han olvidado, o que quizás nunca han experimentado: la espera a que la película salga del laboratorio.

Stephen Dowling ha utilizado cámaras Lomo desde el año 2000.

Tomado de: http://www.bbc.co.uk/mundo/noticias/2012/12/121122_tecnologia_camara_lomo_fotografia_en.shtml