Camera Obscura

I really like the idea of the research blog as it means that I can use it as a reference point for interesting and useful things that I come across during research for my course (even though some of it may not strictly be to do with editing or post production).

It is really useful for me to have this information in one place so that I can keep going back to it.

Whilst researching the evolution of film for my Experimental module I came across this website for the Camera Obscura in Edinburgh.

It's a brilliant website and has a wealth of information regarding the history of the Camera Obscura and how it works and the effects that can be made with this, and other cameras, such as thermal imaging cameras and how to create optical illusions using different cameras and set ups.

http://camera-obscura.co.uk/camera_obscura/camera_obscura.asp

The next time I go to Edinburgh I will definately be visiting the Camera Obscura.

Pictures from the Camera Obscura website:

The How Does It Work? text below is from the website and explains how the camera obscura works.  It's really interesting as we studied pinhole photography in our foundation year.  The text below tells how the camera works like a periscope and channels reflected light onto the concave surface which reproduces a precise image that the camera is seeing.  It must be incredible to see this first hand.

HOW DOES IT WORK?

The mechanics of the Camera Obscura are a cross between a giant pinhole camera and a periscope. At the top of the tower is a dark chamber with a mirror on top which reflects light downwards, passing through three lenses before projecting a stunning image of the city onto a large white table. Your guide turns and tilts the mirror to give a 360° tour of Edinburgh while giving a fascinating and fun commentary. Don’t miss the chance to pick up a passer-by in your hand in this amazing interactive exhibit.


In the centre of the Obscura room is a white painted, concave wooden table. 21 feet 4 inches (6.52 metres) above it is a 10 inch diameter glass doublet lens. A metal cylinder rises another 6 feet 9 inches (2.06 metres) upwards with a singlet lens halfway and a triplet lens 5 inches in diameter at the top. The cylinder projects out of the roof of the Camera Obscura and is covered by a protective hood, open to one side. Under the hood facing out through the opening is a plain mirror protected by a pane of ordinary glass.

The light from any object passes through the glass. The mirror is set at an angle and so reflects the light downwards, through the lens and on to the white table, where an image of the object is visible when the room is darkened. The mirror tilts and rotates to change the view.

The image is not magnified but is reproduced at life size. It is also correctly orientated. In a basic pinhole Camera Obscura the image is upside down and reversed. In this Camera Obscura the mirror and lens turn the image the correct way up. The lenses of course also focus the image. The focus is very precise and the depth of field (area from near the lens to far away in sharp focus) is also very large. This is achieved by having a very small aperture, equal here to F67. The F number is simply the focal length divided by the diameter of the lens. (Focal length is the distance from table to lens. The focal length is 337.7 inches. The top lens is 5 inches in diameter. 337.7 divided by 5 is equal to an F number of 67.54).

If the aperture became smaller still, very close objects would also be sharply focused. But then this would cut out more light, and make the image too dark. With the present 5 inch lens most of the picture is in focus and the image on a reasonable day is bright enough. The large depth of field avoids the need to constantly adjust the focus.

The distances involved in the Camera Obscura are huge when compared to those in a photographic camera. This creates another problem. The lenses focus light in a curve. To overcome this, the table has a concave surface to match the curve of the focus. Nevertheless the image is still less clear at the edge than it is in the centre. This is due to the fact that any lens is weaker at the edge. With an image of this large scale the weakness is clearly visible.

The quality of the image is however excellent. This is due to the present lens system which was installed in 1947 by Barr and Stroud, the Glasgow firm of scientific instrument makers. Apparently in 1853 the image was smaller and less clear than it is today.



MAKE YOUR VERY OWN CAMERA OBSCURA!

Wouldn’t it be great if you could see a view of what is happening outside projected on your bedroom wall! Follow the instructions below and learn how to make your own camera obscura.

In a room Shut out all the light from a room by covering the window with a piece of card or hardboard, cut to fit. Bore a hole through the card or board. An upside down moving colour image of the scene outside will appear on a piece of paper held opposite the hole. Experiment with different sizes of holes and see the effect on the image.

From a box A portable camera obscura can be made out of a cardboard box. First, tape up the box to ensure that no light can penetrate it. Then cut away part of one end of the box and fix a screen of tracing paper across it. At the opposite end cut a 25mm hole in the box, cover this with kitchen foil, tape down the edges and bore a neat round hole through the foil that is no larger than the lead of a pencil. Take the box outside, or to a window, shutting out as much light as possible with a thick blanket. An upside down image of the scene outside will be seen on the screen. ..................................................................................................................................................................

The books listed below are some of the books recommended by the Edinburgh Camera Obscura website.

I am a big fan of David Hockney's work (I thought the film 'A Bigger Splash' was a fantastic film portrayal of Hockney and the story and subjects behind the swimming pool paintings) and am keen to read 'Secret Knowledge'.  In similar vein, I'd be interested to read Vemeer's Camera by Philip Steadman to explore further how the camera obscura may have been used in art, enabling painters to recreate lifelike images.

'Secret Knowledge' by David Hockney For two years, British Artist David Hockney investigated the painting techniques of the old masters, and like any admirable sleuth, compiled substantial evidence to support his revolutionary theory. Secret Knowledge is the fruit of this labour, an exhaustive treatise in pictures revealing clues that some of the world's most famous painters, Ingres, Velázquez, Caravaggio (just to mention a few) utilized optics and lenses in creating their masterpieces.
Vermeer's Camera by Philip Steadman Philip Steadman's remarkable book Vermeer's Camera cracks an artistic enigma that has haunted art history for centuries. Over the years, artists and art historians have marveled at the extraordinary visual realism of the paintings of the 17th-century Dutch painter Jan Vermeer. The painter's spectacular View of Delft, painted around 1661, and the beautiful domestic interior The Music Lesson seem almost photographic in their incredible detail and precise perspective. Since the 19th century, experts have speculated that Vermeer used a camera obscura. However, conclusive proof was never discovered, until now. In Vermeer's Camera, Steadman proves that Vermeer did indeed use a camera obscura to complete his greatest canvases.
The wonderful 1946 British movie ‘A Matter of Life and Death’ (British title) or ‘Stairway to Heaven’ (US title) features a scene inside a camera obscura. It is a fantasy story of a British flyer, played by David Niven, who refuses to die after falling in love with an American WAC (Women’s Auxiliary Corps) during his last moments of life. A beautifully conceived scene in a camera obscura between the WAC and an English doctor is short but effective. You can find it on DVD or in a revival of old movies and it is a delight on many levels.
The Underground Man by Mick Jackson, Penguin, 1998, is a novel about a real 19th century eccentric, the Duke of Portland. In one of the later chapters of the book he visits the Camera Obscura in Edinburgh. Here is a passage from the book: Like my co-spectators I rested my hands on a circular railing and looked down on a broad concave table-perfectly smooth and white – whilst the woman in tweed pressed on with her practiced intonation about the room in which we stood. With one hand she had told of a long wooden rod which hung down from the high ceiling and as our eyes accustomed themselves to the dark she gradually became more visible. Her hands and face had about them a ghostly luminosity. She twisted the rod, saying, ‘… the same principle as the camera. A tiny aperture in the roof allows an image to be cast on the dish below…’