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Gromett has come up with a great idea - the photographic world is full of jargon, [I]ISO, ASA, Raw[I] et etc.
So we thougth we would start a thread for questions and answers. So come on, ask anything photographically and if you know the answer jump in.............
What is ISO and what effect does it have on the picture? where would you use different settings?
Aperture? I (think I) know its the size of the hole, bigger lets more light in etc. But where would you use bigger/smaller ones. And it affects depth of field or something?
Whats the F Stop Number mean?
Lens terminology. I have a 28-80 lense and someone tells me to look for a x-y lense. I have no idea what they mean.
Depth of Field?
Think that is the most important ones that I can remember?
If we go back to film days ISO was a figure that related to how the emulsion on the film would react to light, the lower the figure the slower the reaction. You would use 100 ISO for say a portrait where the subject was static and 400 ISO for sport. The higher the film speed though the less attractive the colours and the bigger the grain.
With digital the figures were still used but instead of grain with the higher figures you got more digital noise which has a similar look to grain. However as technology moves on there is less and less noise(grain). This can is boasting phenominally high ISO figures. This is particulary useful for available light photography. For example I hardly ever use a flash these days for a wedding. The big advantage that digital has over film is that you can change the ISO at will where as with film a film was one speed and that was it so if during a job you wanted different spped film you had to have more than one camera or change film and waste the frames that were left.
ISO used to be known as ASA.
Shutter Speed/Aperture and depth of field
Depth of field - In this example we are photographing a Person. Between us and the person is a wire fence and behind the person is a row of trees. Its a bright day and we set the camera to program setting. The camera does not really know what the most important thing is so it just works out an average setting.
Shutter speed - is the time the shutter stays open for. Most people can handhold a camera at 1/125th second and so the camera sets this - so for 1/125th sec light is allowed to pass through the camera lens. The camera has an aperture that can be set to large or small or many sizes in between and this controls the amount of light that is allowed through at any one time. An aperature of f1.8 allows a lot of light through and F16 allows much less. Aperatures do not go up as 1,2,3,4,5,6 etc but as
F 1.8, 2.8, 4, 5.6, 8, 11, 16, 22, 32 and their are also settings in between all of these depending on how clever your camera is.
light passing through a lens at 1/125sec at F8 means the shutter stays open for 1/125th second and the aperature opens to a diameter equal to F8.
If the above gave you perfect exposure, you would aslo get perfect exposure if you changed the aperture to F11, meaning less light would enter but set the speed to 1/60th so the shutter stayed open for longer.
Depth of field is easier to understand if we call it depth of focus because that is really what it is. If in our example the person is standing 10 feet away from us and we focus on her there will also be things that are in focus - meaning appearing sharp closer to the camera than her and behind her. The aperture controls how much in front and how much behind, it is all to do with light and how it travels.
The higher the aperture number the more depth of focus we have. The depth of focus is also effected by the length of the lens. So with your lens Karl at if you set the aperture to F8 there would be more depth of field with your 28mm than there would be at the 80mm end.
In our example say the camera suggested 1/500th at F11. Our subject is 10 feet away from the camera, the wire fence is 4 feet away and the trees 20 feet.
At F11 on the 28mm setting everything is in focus from 2 feet to 30 feet so we see the fence, the girl and the trees, all sharply focused.
We zoom to 80mm and set the aperture to F4, now everything from 4 feet to 15 feet is sharp and so now the background trees just become a blur, the girl is sharp but so is the fence in front.
So what we now do is literally walk upto the wire fence so it is now only inches from the lens and magically it disappears, we foucus on the subject and now only she is sharp, the wire fence has vanished and the trees are still blurred. The result is a lovely portrait without any distractions. We have controlled depth of focus with the lens length and the aperture.
Why do professional photographers buy digital cameras with more megapixels than the diffraction limit? Are they as gullible for marketing as the point-and-shoot brigade?
Why do professional photographers buy digital cameras with more megapixels than the diffraction limit? Are they as gullible for marketing as the point-and-shoot brigade?
Dave
Do what? what? eh?
Thought this thread was supposed to be clearing confusion not adding to it lol.
Thanks Dave ;p
I was intrigued to see your full-timing aspirations. Where are you with your van btw?
Plans are well in Hand, implementation due beginning of February. Just preparing the business for sale and setting up my new smaller business.
Decided to go with the Iveco 75E15 SelfBuild
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