EDUCACIÓN PLÁSTICA E VISUAL CPI CABO DA AREA LAXE 4 ESO

10 PHOTOGRAPHY USE OF D-SLR CAMERA SUBJECT: PORTRAIT

Kate Winslet, Oscar Party, LA, 2/2009 by Larry Fink

The word photography comes from the greek: "photos" means "light" and "graphein" means "representation by means of lines or drawing". So it can be translated as "drawing with light".

1. The BACKGROUND The development of photography was possible by two main discoveries:

• Invention of CAMERA OBSCURA (1) by Aristotle in 350 a.c. This device was improved for centuries (Leonardo daVinci in the XVth Century, Kircher in the XVIIth Century(2), etc)

• The discovery of some chemicals sensitive to light (or light-sensitive chemicals):◦ By experimenting in 1822, Joseph Nicéphore

Niépce got the first images on a plate made of pewter and coated with bitumen of Judea, placed inside a camera obscura for 8 hours. This one is considered the first photographic images (called heliography): View from the window at Le Gras (1826)(3)

◦ The painter Louis-Daguerre improved the method by using copper plates coated with silver nitrate (nitrato de plata) and exposure time from 15 to 30 minutes. (4) Daguerreotypes (Daguerrotipos)

◦ William H. Fox Talbot developed the Calotype (calotipo) with paper coated with a layer of silver salts to create negative images. After that it is possible to get more positive copies and paper-based process is cheaper than other based on metal plates. (5).

◦ In 1878 Charles E Bennet uses Dry Plate, also called gelatin process (gelatinobromuro de plata)(around 1880) 40 times more sensitive to light. (6).

2.

2. Pinhole Photography (fotografía estenopéica).

Exemplo de foto estenopeica: negativo e positivo (alumnos 3º eso bilingüe curso 2012/13 no CPI cabo da area) (7)

A pinhole camera is a simple camera without a lens. Basically, it is a light-proof box with a small hole made on one side. The process is based on the Camera Obscura, so light from a scene passes through this single point and projects an inverted image on the opposite side of the box. A photographic paper is placed on that side of the box where the image is fixed.

It is necessary to use a shutter to open or close the tiny hole . Up to a point, the smaller the hole is, the sharper the imaxe will be but, on the other hand, darker (supposing the same exposure time).

Exposure time can vary from 5 seconds to hours, depending on the conditions. Related activity:

http://www.edu.xunta.es/centros/cpicaboarea/system/files/u2/pinhole_phoytography.pdf

http://redescolar.ilce.edu.mx/redescolar/act_permanentes/luces_de_la_ciudad/Memorias/fotografia/camara.htm

3. The SLR Camera

(cámara RÉFLEX)

Two parts:

a. The camera lens: It is the “eye” of the camera where the optical lenses are placed. The lens focuses the image on the sensitive film (CMOS or CCD sensor in digital cameras). Each camera lens allows a focal lenght or a range of them.

b. The body

Interesting article: What do DSLR cameras consist of?

FOCAL LENGHT (DISTANCIA FOCAL) is the distance in milimetres from the optical centre of a lens to the imaging sensor (or image sensor) when the lens is focused at infinity.

- The shorter the focal length is, the wider is the angle of view (and viceversa)

- The shorter the focal length, the more depth of field (profundidade de campo).

- A reference:

*Lens with focal length less than de 35 mm are known as wide-angle (obxectivo gran

angular: angle of view more than 60º)

* 35-50 mm – these are normal lenses (obxectivos normais: angle of view of the diagonal around 50º)

* greater than 60 mm are known as telephoto (Teleobxectivos: angle of view less than 35º)

A Zoom lens is a camera lens whose focal length can vary.

http://www.youtube.com/watch?feature=player_embedded&v=y4wGNJPTr6o#!

the APERTURE (apertura in Spanish) is basically the “pupil” of the camera. The diaphragm (diafragma, Sp) works as an “Iris” and controls the size of the aperture (the amount of light that reaches the image sensor or “retina” of the camera). The aperture also determines the depth of field (profundidade de campo). The diaphragm is made of metallic small blades (from 2 to 8) that allow different apertures for light. The size (diameter) of each aperture is indicated by the f-number (número f), which is the ratio of the lens'focal length to the diametre of the aperture. cada subida de F implica reducir á metade a cantidade de luz que entra e viceversa.The size of the aperture has a direct impact on the depth of field, which is the area of the image: larger f-numbers a longer depth of field.

Diaphragm

f/9

exposuretime

1/30seg

focallenght

98mm

Diaphragm

f/22

exposuretime

1/4seg

focallenght

50mm

Understanding APERTURE. (click here for mor info)

The SHUTTER (obturador) is the mechanism that controls the exposure time (tempo de exposición) or shutter speed (velocidad de obturación) is the lenght of time a camera's shutter is open when taking a photograph. The exposure time can be diverse , for instance, the exposure time in the DSLR Olympus E-450 goes from 8 sec. to 1/4000 sec. Long exposures can be done using B exposure (or bulb exposure).

We have to coordinate properly the exposure time (or shutter speed) and the aperture in order to get a desired result. For example, we should use a quick sgutter speed to capture moving objects but as it implies less light going into the camera, we should increase the aperture (a low f-number) to compensate.

Depth of field (profundidade de campo) or focus range (or effective focus range) is the distance between the nearest and farthest objects in a scene that appear

acceptably sharp in an image . It depends on: focal length, aperture and the distance to the depicted object.

Camera ISO. Basically ISO has to do with sensitivity to light. To fully understand this concept, visit the link below:

https://photographylife.com/what-is-iso-in-photography

Interesting webs about photography:

http://ntic.educacion.es/w3/eos/MaterialesEducativos/mem2006/fotografia/index.html#http://foto.difo.uah.es/curso/index.html

http://redescolar.ilce.edu.mx/redescolar/act_permanentes/luces_de_la_ciudad/Memorias/fotografia/camara.htm

Taking a portrait. A portrait can reflect much more information about people than just their physical appearance. The particular selected gesture, how the light reach the face, the colours or the absence of them, etc. All these aspects affect the quality of the portrait. Lighting is decisive as it will enhance particular features of the face. The use of frontal lighting can maximize the symetry or the use backlighting will blur those features. Side lighting is good for giving some mistery and dramatism through the play of light and shadows. The camera angle can allow more expressive options.

activity: a portrait of a peer

Groups of two students

Each student will photograph his/her peer. The portrait is going to be used to introduce each student in the Seascape project's book.

All the portraits must be done with the DSLR Olympus E-450 using MANUAL mode, manual focus, no Flash and using the viewfinder. Both camera lenses can be used (14-42 and 50-140) .

After finishing the portraits, each student must submit the photo by sending it by email to the usual email address. The following information must be included in the email:

date

Focal length

Aperture

Shutter speed (exposure time)

ISO

The file will be sent in JPG format

debuxo.cabo.da.area@gmail.com