This is something that I've sent to people from time to time in my PMs, hopefully explaining some camera settings in layman's terms. It probably needs some work though.
***********************
Good places to start:
http://www.cambridgeincolour.com/tutorials.htm
www.dpreview.com : good forums and reviews, picture galleries are amateurish and the user base is usually amateurs.
www.fredmiranda.com : great forums and a buy/sell section. Slower than DPReview, but the people there are more knowledgeable and the pictures that people post are usually decidedly more professional than the ones at DPReview. Old users here sometimes complain that the general quality of the forums and posted pictures have declined over the years because of a steady influx of amateurs from dpreview, Canon Digital Photography Forums, and others.
http://photography-on-the.net/forum/ : also called Canon Digital Photography Forums, another good forum, geared more towards amateurs than FredMiranda.
Aperture
There are actually two predominant uses of aperture:
1. The physical hole that?s in the lens that lets light through. The diameter of the hole in millimeters can be calculated by dividing the len?s focal length by the aperture value. Ex. The actual physical diameter of the aperture of a 50mm f/1.8 lens is 50mm / 1.8 = 28mm, or 2.8cm. The diameter of the aperture of a 500mm f/4 lens is 500mm / 4 = 125mm, or 12.5cm!
2. The light gathering ability of the lens. This is the use predominant among photographers. A 400mm f/2.8 lens has the same light gathering ability as a 50mm f/2.8 lens, despite having a much bigger physical aperture size.
The larger the f-number, the smaller the size of the lens opening, or aperture. So from large hole to small hole, f/1.4, f/1.8, f/2.2, ? f/16, f/32, etc.
Depth of Field (DOF)
The smaller the aperture (larger the f-number), the greater DEPTH of field (NOT field of view) the picture will have. Depth of field is the depth of the image that is in focus.
Ex. If you focus on something 4ft away, an aperture of f/8 will, say, having everything 3ft away to 20ft away in focus. An aperture of f/32, on the other hand, will have everything from 2ft away to infinity in focus. The smaller aperture, f/32, has greater depth of field than the larger aperture, f/8.
On the same note, if you focus on an object 4ft away, and have an aperture of f/1.4, your depth of field will only be a few centimeters! This is useful for isolating subjects, such as in portraiture where you want the face to be in focus but want everything else to be out of focus.
?Stopping Down? is basically ?making the aperture size smaller.? When you stop down a lens you make the aperture smaller, from say, f/3.5 to f/8.
NOTE that lens sharpness decreases as your aperture size decreases. Lenses generally have their maximum sharpness at f/8. Anything smaller (f/16, f/32) will result in a loss of image quality because of diffraction. This is the trade-off between depth of field and sharpness.
Shutter Speed
The time the shutter is open. The longer the shutter is open, the more light is let through. The shorter the shutter is left open, the less light is let through.
Uses:
Long (slow) shutter speeds are used to make that silky water flowing effect in waterfalls and rivers and streams, or the mirror effect in lakes and the misty effect in ocean surf along the coast. They are also used for star trails.
Short (fast) shutter speeds are used to freeze actions, like freezing a horse in midair as it jumps over something, or freezing a boxer?s punch as it connects his opponent.
Rules of Thumb:
Handholding: On average, to get an adequately sharp shot of something while handholding, reciprocate the focal length of your lens and you get the shutter speed that you SHOULD be able to handhold at and still get a pretty sharp picture. I say ?pretty? because chances are it still won?t be as sharp as using a tripod, but the sharpness should be acceptable.
Ex. If you have a 50mm lens, a 1/50s shutter speed should be fast enough for you to handhold and still get a steady, sharp-ish shot. If you have a 200mm lens, a 1/200s shutter speed will be needed. Of course this varies with people and their abilities. If you?re sniper-steady, you can get away with slower shutter speeds. If you?re jerky, you may need faster shutter speeds.
Crop Factor
Note that different cameras have different sensors sizes, and the focal length in mm of a lens is standardized to the full frame sensor size of 35mm. Cameras like the Canon 20D, Rebel XT, and 30D have a smaller sensor that introduces a 1.6x crop factor to the focal length. Nikon cameras introduce a 1.5x crop factor. Current Olympus cameras introduce a 2x crop factor.
It's hard to explain without pictures, but suffice it to say, if you own a camera with a crop factor your len's focal length will actually be equal to (lens focal length) x (crop factor). So a 200mm lens on a 1.6x crop factor Rebel XT would effectively be 320mm. On a 1.5x Nikon, the 200mm lens will be 300mm. This is great for telephoto lenses because you effectively get extra reach, but it also means that lenses that were wide-angle on full frame cameras are no longer as wide on crop bodies.
For the above handholding technique, you have to keep crop factor in mind. If you have a Nikon with a 200mm lens, you must handhold at shutter speeds of 1/300s or faster instead of just 1/200s.
Timings:
Anything 1/4s and below will start to get you some nice water flowing effects. Decrease the shutter speed into the seconds for more smoothness.
Speeds of 1/400s and faster should be able to nicely freeze any action, with the exceptions of bullets, etc.
Speeds in the order of minutes to hours are used for star trails.
Technique:
For the most steady handholding, use the viewfinder on a camera because this gives you the most steady brace of the camera against your body.
Breathe slowly, and shoot at the end of your exhale.
A natural reaction of people after pressing the shutter is to immediately take their finger off the shutter button, like clicking a mouse button. This releasing will introduce added movement, and your shutter may not be fully closed again at this time. When going for a steady handheld shot, press the shutter button, and keep it pressed until the shutter has made its complete motion. Then let your finger off.
ISO
The film or sensor?s sensitivity to light. A higher ISO number means the sensor is more sensitive to light, and will gather more light as a result. A sensor set at ISO 400 will gather twice the amount of light as the sensor at ISO 200 in the same amount of time.
The higher the ISO, the more noise is introduced into the picture.
Putting It All Together
For example, low-light shot possibilities:
1. low ISO, long shutter speed, small aperture (ex. f/8)
Advantages: noise-free image and a large depth of field.
Disadvantages: Will probably have to use a tripod because of the long shutter speed. This is also not good for moving subjects because they will blur due to the long shutter speed.
2. low ISO, short shutter speed, large aperture (ex. f/1.8)
Advantages: noise-free image and the shutter speed will perhaps be fast enough to freeze the subject without blurring and allow for handholding.
Disadvantages: Depth of field is very short, and this can be good or bad depending on the situation. Ex. Bad if you?re taking a picture of a group of people standing at varying distances to the camera.
3. high ISO, short shutter speed, small aperture
Advantages: Shutter speed will perhaps be fast enough to freeze the subject without blurring and allow for handholding. Better depth of field.
Disadvantages: Noisier image.
4. high ISO, long shutter speed, large aperture
Advantages: none, other than being able to actually GET the shot.
Disadvantages: Noisier image, difficult to keep the subject un-blurred if it?s moving, difficult to handhold adequately, small depth of field.
This last case is a huge problem for people who shoot in places like concert halls or indoors where there?s not a lot of light. Basically it boils down to getting a workably fast shutter speed at the utter expense of a clean image and depth of field. All too often, maxing out the ISO and having the lens wide open is still not enough...
Pushing Your Photos
There is another 5th method, and that's pushing your photos:
The situation when you push a picture:
The light levels are low and you need to get a picture. You NEED a shutter speed of 1/250 sec to get the picture. You've increased your aperture as wide as it can go and your ISO the highest it can go, but alas, this only nets you a shutter speed of 1/60 sec, much too slow. So basically you either:
a. Switch to manual and force the shutter speed to 1/250 sec.
b. Decrease your exposure compensation to -3 stops, which will net you 1/250 sec.
You shoot the picture. When you process the picture later on the computer, it will be severely underexposed because of the too-fast shutter speed. What you now do is "push" the picture using your RAW software like Adobe Camera RAW (comes with CS2, maybe PS7). Basically there will be an option to increase the exposure in the software. You increase the exposure by 3 stops in software, and depending on how nice of a sensor you have, you can actually push out details and colors out of the underexposed photo! The downsides to this is that the image will be noisier than usual, and if you try to push too far the image will look like poop, which is when you have to back off.
This is why it's so important to shoot in RAW. RAW saves a lot more image data than JPEG, especially image data that you cannot see from just a cursory glance at an image. Using pushing and pulling techniques brings out this latent data, which can really save your butt.
Post Processing
For post-processing, it really depends on the scene in question.
Here's my general workflow:
1. Open my RAW files in Phase One Capture One Pro.
2. Adjust white balance, exposure, contrast, color saturation.
3. Save as TIFF.
4. Open TIFF in Photoshop CS2.
5. Do framing and cropping, noise reduction with noise ninja, black and white conversion if need be, and a little contrast/exposure/saturation if I didn't get what I wanted from Capture One.
6. Sharpen.
7. Save as PSD, TIF, and JPEG.
Tips that can make your photos vibrant and jump out:
1. Reduce noise so that they're smooth.
2. Selectively saturate colors that you want to stand out.
3. Sharpen with USM using magnitude 1-50 and radius 20.
4. Selectively DEsaturate colors that you want to de-emphasize, ie. blue haze