I recently wrote this guide to help a friend get to grips with his new Canon 400D - but figured I'd post it here in case its useful to others:
The following guide is designed for users of Canon DSLR cameras - but will work equally well for Nikon users (and others) as the principles are the same. This guide assumes you know where the various settings and buttons are on your camera, even if you don't know what they all do! I have simplified some language in my guide to make it more user friendly to beginners (so don't bitch about my description of F.Stops for example!)
Have you ever wanted to get more out of your DSLR, but don't know where to start? If you are using your DLSR in the pre-programmed automatic modes, then essentially you have an expensive point-and-shoot, and are wasting much of the functionality of your camera. (and need slapping upside your head).
To those of you wanting to break out from using the automatic modes, I suggest shooting in Av mode (known as aperture priority mode), and configuring your camera as follows:
- Av mode (from the top dial).
- Evaluative / matrix metering (its probably set to this already if you've not changed the exposure mode, but check your manual to see).
- Center focus-point only.
How to shoot in Av mode:
In Av mode you basically have two settings that you'll need to worry about adjusting, depending on your shot:
1) F.Stop (sometimes called the depth of field). The smaller the F.Stop number, the less of your shot will be in focus (smaller depth of field). Also, the smaller this number the higher the shutter-speed will be.
2) ISO setting - which is basically the "speed" or sensitivity of your cameras sensor. The higher this number the higher your shutter speed, but the more noise (grain) you will have on your images.
Based on what you specify for these two settings, your camera will then automatically work out the shutter speed needed to expose the shot correctly.
To shoot in Av mode, half press the shutter and look at the shutter speed that is being reported in the viewfinder. If you need a faster shutter speed (to ensure your shot is not blurred), then you have two options:
1) Reduce the F.stop - so the shutter speed increases (but bear in mind less of your shot will then be in focus)
2) Increase the ISO setting, which will increase the shutter speed (but will mean more noise on your shots as you go to the higher ISOs)
Often you will need to adjust both settings in one combination or another. After a while you will get a feel for which settings you'll need to use in what situations - and often you won't need to check the shutter speed before you shoot, as you'll "know" that the settings you have chosen will work. Shooting in Av mode lets you get more creative with your shots, as you have the control over how blurred the background of your shots will be, and how much of your subject will be in focus.
Some general rules to help you take better photographs:
- When shooting outside in good light, try to use ISO 100 or ISO 200 (sometimes you might need ISO 400 if the light is bad).
- For shooting indoors (without flash) you will likely need to use ISO 800 or ISO 1600.
- The highest F.stop setting you would normally need to use will be F8 or F10. Usually this high setting would only be used for landscapes etc where you want everything in focus right out to infinity. Going above F10 can result in reduced sharpness on many lenses. The "sweet-spot" for most lens in terms of sharpness is around F6-F8.
- For portraits etc try to use an F.Stop of F4, F5.6 or F6.4 (depending on your subject distance and focal length) - as this will help to blur the background and isolate your subject.
- For portraits - always auto-focus on your subjects eyes, not their nose - otherwise if you are using a small F.Stop and focus on their nose, your subjects eyes may end up out of focus!
- When shooting with an image stabilized lens - try to have a shutter speed that is at least equal to your focal length. E.g if you are shooting with the zoom at 50mm, try to aim for a shutter speed of at least 1/50 second or higher - to avoid camera-shake. Obviously if you are using a monopod or a tripod then you can potentially go much lower with the shutter speed.
- If you are shooting with a non-image stablised lens, you should aim for a shutter speed of 1.5x or 1.6x the focal length used. E.g if you are shooting at 50mm with a non-stabilised lens, try to aim for a shutter speed of at least 1/80 second or higher. As you get more experienced you'll find you can shoot at lower shutter speed and still get sharp shots.
- Don't forget that image stablity is great to eliminating camera shake, but won't freeze movement if your subject is not stationary. The only way to freeze movement is to have a sufficently high shutter speed.
- The closer your subject is to you (and the further away the background is from your subject) - the more blurred the background will be. You can accentuate this effect by using a lower F.Stop setting. Background blurring is also more visible the longer you focal length (i.e when you zoom more).
How to use the histogram:
An often misunderstood (or just plain unknown) function on DLSRs is the histogram. On most DSLR's you can review images with the histogram on screen.
The histogram is your tool to see if the shot you have taken is exposed correctly, and if it has any clipped highlights and / or shadows. Clipped highlights or shadows are bad, as you have lost the data in those areas and can't get it back. Ever taken a shot and had a completely white sky? Thats a good example of a clipped highlight (unless of course it really was a blanket of pure-white clouds that day!)
When looking at the histogram for a shot you'll see a bunch of vertical lines, usually clustered across the length of the histogram, and maybe grouped together at various locations on the histogram. The left of the histogram represents DARK pixels, and the right of the histogram represents LIGHT pixels (with the middle being a gradation from light to dark accordingly). The extreme left side of the histogram is pure BLACK, and the extreme right side is pure WHITE. The vertical height of each line represents how many pixels in your image exist that that level of brightness or darkness.
A very dark scence for example would have almost all the vertical bars clustered towards the left side of the histogram, whereas a very light scene would have all the bars clustered towards the right side.
If you have a histogram with a bunch of vertical lines clustered at either the extreme left or the extreme right, then there is a good chance you have either blown (clipped) your highlights (if its on the right) or shadows (if its on the left). Most DSLRs also have an option to show clipped highlights on your image as a flashing area to help you see whats happening.
The aim is to shoot your scene in such a way that all the pixels exist between the left and right hand extremes of the histogram, with no data being clipped. If you take a shot and some data is clipped off either end, then change you camera settings to include either some positive or negative exposure compensation (depending on if its the shadows or highlights which are clipped), then shoot again and check the histogram to see if you have a correctly exposed shot.
Some scenes which go from deep shadows to bright highlights present a problem for cameras. Your camera will be unable to capture all the information in the scene (known as the dynamic range), due to limitations of the cameras sensor. In these situations you have two choices:
1) Decide which end of the data you wish to sacrifice (either the shadows or the highlights), then adjust your exposure compensation accordingly.
2) Take multiple shots - one exposed for the shadows, one for the highlights and one in the middle, then combine them together on your PC. This is known as HDR photography. I'm not going to explain this here as its a more advanced technique.
If you follow the above tips you should find you get more "keepers" when you are out taking photos, and with a bit of luck you might even take better shots!