Photography Basics #5: Capture clear photos

In the previous installment of this photography basics series, I taught about composition.  In this installment, I’ll teach you all about focus and why your photos may not be as sharp as you’d like them to be.
This morning, I got an email from one of the students in my online beginner photography class who said she spent $2,000 on an expensive camera and another $1,500 on a high-end lens.  Still, her pictures don’t look as sharp as she would like them to, and wondered why that is.  I have to admit that I get this type of question SOO OFTEN that I dedicated an entire WEEK of training in my beginner class to teaching about how to get crystal clear and sharp photos.
It is not uncommon for photographers to think that something must be wrong with their equipment if the photos don’t come out sharp, but most of the time I find that the reason is simply a product of mistakes the photographer makes when shooting.  You can avoid those issues by understanding how to properly focus your camera.

The #1 focusing mistake of beginning photographers

The #1 mistake I see from beginning photographers in terms of getting clear pictures, is that they aren’t being precise with their focus.  I often ask students where they are focusing, and I get answers like, “On the model’s face.”  The fact of the matter is that “the face” is far too large of an area to focus on for intimate portraits.  Allow me to explain why…
Suppose you’re taking a portrait of someone.  Now that you’ve learned how to use shallow depth-of-field from the second article in this series, you want to use it all the time in your portraits to get a creamy background behind the subject.  This means you’re usually shooting your portraits at f/2.8 or a similar low aperture.  Suppose, also, that you’re using a 100mm lens and standing 7 feet (2.1 meters) from the subject.  Did you know that, with these settings, that only 1.4 inches (3.5 centimeters) of the photo sharp?  That means that, if you focus on the person’s cheek, their eyes and nose will be partially blurry.
So if you want your photos to come out crystal clear and sharp, you need to focus PRECISELY, and make sure you have enough depth-of-field to make the subject come out sharp.  When shooting portraits, you will almost always focus on the person’s eye, since that is where the viewer of the photo will look first.  For landscape photographers, check out this article on where to focus in landscape photography.

How to focus on one spot

When you were shooting in automatic mode on your camera, the camera would automatically find the subject and focus for you.  Now that you’re shooting manually, it’s time to take control of your focus as well.
Your camera ALWAYS focuses on one specific spot in the scene.  It is physically impossible for a lens to focus on two spots at once.  When you look through your viewfinder, you see a bunch of dots (Canon) or small boxes (Nikon).  Those markings show you where in the frame the camera is focusing.  This spot generally blinks red when the camera sets focus.
In the picture below, I chose to focus on the ant on the flower, since that is where I wanted people to look.  To do this, I set the camera to spot focus and used the four-way selector on the back of my DSLR to move the focus point onto the ant.

Notice the red illuminated focus point right on the ant? That’s where I’m setting the focus for this shot.

Sometimes, the spot in the picture where you want to focus will not have a focus point available.  This is especially true on entry-level Canon Rebel or Nikon D3200 DSLRs, which do not have many focus points.  If you find that this is the case, check out this article on focusing and recomposing.

Focus Selections

I hope I didn’t confuse you earlier when I said that the camera can ONLY focus on one specific spot in the photo.  There are ways that you can activate multiple focus points at once, but in doing so, the camera is just choosing the best of both worlds and compromising between the focus selections to set the focus in the middle somewhere.
99% of the time when I’m out shooting I use spot focus, which allows me to move around the focus point in the viewfinder.  My thumb has become adept at constantly moving around the focus point using the four-way selector on the back of the camera as I compose a shot through the viewfinder.  Spot focus is great because you have exact control over where the focus is placed.
However, there are other focus selection options on most DSLR cameras.  Other than spot focus, you have the ability to choose a small group of between 3 and 5 focus points and tell the camera to choose the best of those points, or you could set your camera to determine which focus point to use all on its own.  I never let the camera take control of focus–it’s a recipe for blurry pictures.  When I’m shooting sports or fast-moving wildlife, I’ll sometimes set the camera to use any of the center area focus points and choose the best one, because the action happens faster than I can move the focus point.
Although there are certainly situations to use other focus selections, I would encourage you to use spot focus and get used to constantly moving around the focus point around the frame as you shoot for the next few months.

Focus Modes

Aside from selecting which focus point(s) the camera is using, you also need to set which type of autofocus the camera will use.  For most uses, you’ll want to leave your camera on “AF-S” (Nikon) or “One Shot” (Canon).  This means that the camera will acquire focus when you press half-way down on the shutter button, and then take the picture when you finish pressing all the way down on the shutter button.
The other main option is continuous focus (displayed on the camera as “AF-C” for Nikon cameras and “AI Servo” for Canon cameras).  This mode is used when the subject is moving.  Suppose you’re shooting a soccer player running toward you.  If you use one shot, then the camera focuses when you press half way down on the shutter, and by the time you finish pressing all the way down, the camera takes the picture.  In that split second, the athlete will have moved, so the picture will not turn out sharp.  Continuous focus (AF-C or AI SERVO) means that the camera continues to find focus all the way up to the instant that you snap the picture.
So why wouldn’t you want to use continuous focus all the time?  Because it’s slightly less precise than one shot.  So here’s the rule… use one shot (“AF-S” on Nikon, and “One Shot” on Canon) for all shots where the subject is reasonably still like landscapes or most portraits.  Use continuous focus (“AF-C” on Nikon, and “AI Servo” on Canon) for all fast-moving shots.
Note: Canon users will also see the option for “AI Focus” when choosing a focus mode.  There is a specific use for this, but honestly it’s just outdated technology.  I have tried it extensively even in the best case scenarios for this focus mode and have always achieved better results with AI Servo.

Source : imrovephotography-basic#5