After our son was born I started noticing the amazing photos others were taking with semi-professional and professional digital SLR cameras and I knew I had to take the leap from “point-and-shoot”. Opening the box to my spanky new DSLR, I was overwhelmed with settings, options and buzzwords. I wanted to take awesome photos right away — not get an engineering degree in optics!
Once I finally sorted out all the jargon I was relieved to understand how simple DSLR photography really is. This is the quick-start guide I wish I had back then…
The goal is to get a shot that is sharp, bright and clean. In outdoor sunlight this is easy. (You could just use the camera’s “auto-mode”.) It’s really for low-light indoor shots that you have to know what you’re doing.
It turns out that the qualities of sharpness, brightness and graininess are trade-offs among each other. So the trick is to adjust the camera in low-light to get the right balance of each.
ENEMIES OF SHARPNESS:
1) Poor “original” focus.
Auto-focus doesn’t always get it exactly right. You might have to use the manual focus to get the subject as sharp as possible.
2) Camera shake
If you got the original focus exactly right, the subject will still come out blurry if the camera shakes even a little while the shutter is open. If the shutter is open for a long time, then you are more likely to see blur from camera shake.
To minimize camera shake on hand-held shots, you should use a “fast-enough” shutter speed. As a rule of thumb, “fast-enough” is 1/30th of a second for a 30mm zoom length, 1/60th of a second for a 60mm zoom length, and so on. Note how the numbers sort of match. (When the camera doesn’t have settings for these exact speeds, use the closest faster speed. e.g. 1/60th of a second for a 50mm zoom.)
3) Subject movement
Even if your original focus is exact and you don’t shake the camera at all, the subject must be in the same place while the shutter is open, or you will get some amount of blur from subject movement. The longer the shutter is open, the more potential there is for motion blur. The faster the subject is moving, the faster the shutter speed must be.
4) Large aperture
The aperture is the size of the hole in the lens that the light comes through. It turns out that a large aperture will produce blurriness for objects behind (and in front of) the original focal point. This can be an acceptable, even desired, type of blur since you can use it to make a sharp subject stand out from an otherwise blurry background. Using this effect for shots of people in particular will give your photos a professional quality that a typical point-and-shoot camera can’t achieve.
ENEMIES OF BRIGHTNESS:
1) Low light!
Of course there’s not much you can do about low light if you are indoors and trying to avoid a yucky-looking flash shot. Or is there? Try turning on some lights or opening a curtain. Light is the “raw material” you’ll be trying to make the most of when adjusting your camera. Increasing the available light is a no-tradeoff solution and your best option for increasing brightness whenever possible.
2) Fast Shutter speed
Fast shutter speed is great for avoiding blur from camera-shake but a fast shutter doesn’t let in a lot of light. So to keep the shot acceptably bright you might have to stabilize the camera so you can use a slower shutter speed.
Alternately, you can keep the fast shutter speed but use a higher “film sensitivity” (measured with ISO numbers). Higher sensitivity film can “absorb” the necessary light quickly during a fast shutter shot, but more sensitive film produces a grainier image. This is also true of the electronic sensor found in a Digital SLR camera that replaces film. However a DSLR lets you change ISO sensitivity settings on the fly — without opening the camera to swap film as with a traditional SLR.
3) Small Aperture
The aperture is the size of the hole light comes through, so a small hole naturally lets in less light.
You can use a larger aperture setting when you need more light, but this will have the effect of blurring objects far enough behind and in front of the focus point. (Again, this might be okay or intentional, depending on the type of shot.)
Aperture is measured in “f-numbers”. The highest f-number corresponds to the smallest aperture (hole size). I find this to be counterintuitive but that’s just the way it is. So to increase brightness using aperture, choose a lower f-number.
As you’ve probably noticed, there are trade-offs involved in getting acceptable brightness and sharpness without graininess. The controls at your disposal to manipulate these factors are available light, shutter speed, aperture, and ISO sensitivity. As a general approach I recommend the following:
First increase the available light in the room whenever possible. Next start with the ISO sensitivity set as low as you hope to get away with to avoid graininess. Then, using the camera’s “shutter priority mode”, set the shutter speed to the slowest setting that will prevent motion blur (using the rule-of-thumb described above). Your camera will select an aperture large enough for your chosen shutter speed and ISO setting.
The camera will warn you if it cannot offer an aperture big enough. If this happens, or if the camera-selected aperture does not produce enough sharpness behind the subject, then either:
1) find a way to increase the light
2) find a way to stabilize the camera and use a slower shutter speed
3) increase ISO sensitivity, at the cost of a grainier image.
Another approach if you don’t mind (or actually want) a blurry background: Switch to your camera’s “manual mode” and set a low ISO and the minimum “no-motion” shutter speed using the same rule-of-thumb from above. Then set the f-number to the smallest setting that your lens allows. Finally, increase the ISO sensitivity setting until acceptable image brightness is achieved.
This should produce the sharpest, brightest, cleanest shot your camera is capable of…