Part 2
The Course
Last month we discussed what was actually required to take a picture. A camera, film, or memory card on a digital and light. Just these three things will allow us to take a picture. Of course it's understanding how these three things relate to each other that produces average pictures, or great pictures. Modern electronic cameras will do most of the work for you and allow the three elements to combine to produce very satisfactory results. However GP Online has never been about producing satisfactory results, no we are aiming for great results every time. More importantly if the results are not great, then you understanding why they are not.
I say it again and again, your eyes and brain have to learn to see a scene, or subject like the film and your camera does. As an example if you are standing on a cliff top looking out over the vista everything appears to be in focus to you. This is simply as you look round your eyes focus to the spot where you centralize your gaze. Try looking out over the scene and concentrate on something in the mid distance. Now without moving your gaze you will see in the periphery of your vision, in fact the close foreground, and far distance are actually out of focus.
Well simply remember the camera takes in the whole scene so cannot be selective about focus when you are viewing the print.
So to recap. We need light and we need to control the amount of light that enters the camera, just as the iris in our eyes widens. and closes depending on the amount of light. This light then burns an image onto the film and with any luck the print that is produced will be the same as what we saw through the viewfinder.
So this month we are concentrating on how the light is controlled. You know from last month that light readings tell us about aperture, shutter speed and film speed. You also learnt the basics that you can control the amount of what's in and out of focus in a scene by using the aperture. You also learnt that you could control how much of a picture is affected by motion blur by adjusting the shutter speed. Then finally film speed could be used depending on the amount of available light.
So first things first let's look at how a camera shutter works. Most people assume that it is like an iris that opens and closes from the centre out and then in. If it did work like this of course the centre portion of the image would get far more light as it is open the whole time, whilst at the edge it would only be a fraction of the time as it opened and closed.
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This is a leaf shutter. As you can see as the iris opens more light is given to the central portion, so really the central section gets more than twice the light of the edge. This is fine unless you are using shutter speeds in tiny fractions of a second. Like 1/250th as example. |
So with the 35mm SLR the manufactures overcame this by using a blind, or curtain method. With this system a blind moves across the back of the lens from left to right opening the film up to the light from the lens. Then a second curtain moves across again from from left to right covering the film. So all of the film gets exactly the same amount of light.
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| As you can see in sample 1 the blind is closed and no light is reaching the film. Then the first blind begins to move from left to right and after a duration the second blind follows. Notice that the film is not exposed all in one go, and it doesn't need to be. The gap between the blinds is the duration of your shutter speed. Obviously if you were using a slow speed then all the film would be completely exposed before the second blind followed across. The point is, as it follows the same direction as the first then the amount of exposure to the film is perfectly even. Clever eh! | ||
Fair enough I hear you say, but did I really need to know all that in detail? OK let's imagine that you are in a studio and the flash which has a far shorter duration than your shutter speed fired at position 5 above. That's what is called sync speed. It sync's the flash to fire at a shutter speed that allows the whole of the film to be exposed. 1st curtain right across, second curtain, not quite started yet. It's not so likely to happen in the studio truth be told, but just wait until we get into the fun of fill in flash in later lessons. If you don't understand how then you cannot possibly know why. See how we are building the foundations for great glamour pictures.
Next we need to understand diaphragm, or aperture. This has been explained fully in an earlier article and is very accessible to the beginner. Close Window To Return.
Next understanding and reading light. I have checked earlier articles and although they cover the subject it is studio based, so I thought maybe a little delve into light metering here would help.
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Centre Weighted
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Matrix
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| The general Light reading just simply reads all the light coming in. It cannot compensate for very bright and dark areas. | Spot metering does just that reads the light on a single spot, although obviously it would be better to place the models face centre of the frame when actually taking the reading. | With centre weighted the camera takes a reading and then another and splits the difference. | Finally matrix is where the camera takes a reading from several spots around the scene and using a program works out a mean average. |
I hope you understand more about the different types of metering your camera offers you.
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Personally for a scene like this I would take five readings as indicated and work out the best solution for this problem. The model is standing in shade and the background is very bright. I'll explain more fully in later lessons why you need to understand the capabilities of the film you are using as well, so that the picture is much more than just a compromise. For reference the most important reading from this picture must be number 2 as skin tones should always be the first consideration. |
So your project for this month.
Photograph something moving, anything you like. Cars driving down the road, buses, trains whatever. Try and pick something that is at roughly the same speed. Take your first picture at 1/30th next at 1/125th and last at 1/500th. If you have a waterfall nearby even better. Set your camera on Shutter priority so that the camera program will take care of the aperture for you. If you have a large zoom or lens then you better tripod the 1/30th shot. Have fun and see you next month when we continue with the basics, but start getting into film and colour. Remember this course is all about producing on film what you see through the viewfinder.
©Glamour Photo OnLine 2002