How many times have you returned from a shoot with some photographs you are really excited about only to find out they are out of focus. That’s always very disappointing and often frustrating. And it happens all too often to me. At the Joshua Tree Gathering this past March someone asked the question, ”How many ways can a photograph be out of focus,” and that got me thinking. This would be a fun article to write.
But let’s get something straight from the start. Not all ‘out of focus’ photographs are out of focus. They may not be sharp but that can come from two causes. They can actually be out of focus or they can be blurry. This may seem like a subtle distinction but it’s an important one. So let’s take them one by one and explore their causes and solutions.
But before we do, I want to make another very important point. A photograph that is out of focus or blurry is not always a bad thing. Often times the artist does it intentionally because that is his or her artistic vision. When it’s done intentionally to create an expressive photograph then it’s not only OK, it’s necessary. It’s when it’s unintentional that we get frustrated and loose great moments.
But now, let’s get into the details. We’ll talk about blurs first.
Blurs
Blurry photographs are caused by movement, either the camera or something in the scene like a bush or a flower. You may have focused everything correctly but the image is still fuzzy because the camera moved or a gust of wind came up just when you pressed the shutter.
When the camera moves, everything is fuzzy. Nothing is sharp. The degree of fuzziness depends on how much the camera moved. If you’re spinning rapidly on a merry-go-round, any pictures you take facing out will be greatly blurred. But if you just move the camera slightly because you pressed the shutter button too hard, the blur may be nearly imperceptible until you look at it very closely.
Sometimes blurs like this can produce very interesting and moving results. In fact, there is a movement of ‘Impressionist’ photographs that intentionally move the camera to create blur effects. Photographers are creating some imaginative and inspirational photographs with this technique. A variation is to keep the camera steady but zoom the lens during the exposure. This can be lots of fun.
The other kind of blur is when an object in the frame moves. This could also be unintentional or intentional. If you’re photographing a flower and your intent is to show it in all of it’s glorious detail and a puff of wind moves it just as you snap the shutter, you’re going to be disappointed. But if you want to create more of an ‘Impressionistic’ image with swaths of color brushed across the frame, then the flowers blowing in the wind is exactly what you want. My good friend and great photographer, Paul Martini, has been exploring blurs out in the desert along the railroad tracks. Here’s a stunning example of his extraordinary work.
© by Paul Martini, used with permission
Causes of Blurry Photographs and Their Cures
Hand held photography always runs the risk of getting blurry photographs because of camera movement at the moment the shutter button is pressed. Landscape photographers eliminate that problem by using the greatest image stabilization device ever created, the tripod.
But you can still get sharp hand held images if you follow this simple rule. If your shutter speed is fast enough a slight movement of the camera will not show up. The rule of thumb here is to have a shutter speed as least as fast as 1/(lens focal length). For example, if you are shooting with a 50mm lens then your shutter speed must be 1/50 of a second or faster. If you’re shooting with a 400mm lens then you need a shutter speed of 1/400 of a second or faster. If you have an image stabilized lens then you can shoot with slower shutter speeds. For example, if your image stabilized lens gives you a 2 stop advantage then with the 50mm lens you can photograph at 1/12 of a second and with your 400mm lens you can photograph at 1/100 of a second.
And you can still get blurry images when photographing from a tripod. There are lots of ways this can happen. First and foremost is touching the camera or tripod when the shutter fires. Pressing the shutter button is the way this can happen. That’s why we use remote releases connected to your camera. You press the button on the remote release which triggers the shutter – hands free.
There is another more subtle cause of blur – camera vibration. This is generally caused by ‘mirror flap.’ In digital SLRs when the shutter is activated a mirror inside the camera flips up out of the way, allowing the light to pass through to the sensor. When the mirror snaps into place it sends vibrations throughout the camera. These vibrations actually travel not only through the camera but through the tripod all the way down to the ground. You can prove this to yourself. Rest your hand on your tripod leg and fire the shutter. You’ll fell the vibrations from the mirror flap. Mirror flap only becomes a problem at the longer focal lengths, say 100mm and up with the effect getting stronger as focal lengths get higher. When you get up to 300mm and 400mm and above it’s a big problem.
There are a couple of ways to eliminate mirror flap. One is to use mirror lockup. This means you press the shutter twice – once to flip the mirror up and again to fire the shutter. If you wait a few seconds between the first and second shutter press you will give the vibrations in the camera and tripod time to settle down. In some cameras you can set the drive to a 2 second or 10 second delay. With mirror lockup turned on a single press of the shutter will flip up the mirror, wait 2 seconds and then fire the shutter. Yet another way to eliminate mirror flap vibrations is to photograph while in live view. The mirror is already up. My personal preference is mirror lockup with the two second delay. When I’m shooting with my 100-400 lens I’ll often use a 10 second delay.
Even when shooting from a tripod another thing that can cause blur is anything that disturbs the tripod. If you’re touching the tripod when the shutter fires you may giggle it just a little which would transfer the motion to the camera. So don’t be touching the tripod either when the shutter is pressed. But wind can also move the tripod. I keep the strap on my camera because when I’m walking around doing hand held photography I want the protection of the strap around my neck. But on a tripod the strap can blow in the wind and that can cause camera motion. So I hold the strap to keep it from flapping when the shutter fires.
Focus
The other cause of fuzzy photographs is that they are not focused correctly. You can tell when this is the problem because there will generally be some part of the image that is in focus and other parts that are not. For example, the distant mountains may be in focus but the foreground is not. or it may be the other way around.
This effect often times can be desirable. When photographing people out of doors it’s very appealing to have their face sharp but the background out of focus. Also in macro photography it’s common to have the bee in the flower in sharp focus but everything else out of focus. So once again, if it’s intentional, if it supports your creative vision, out of focus is a good thing. But if it’s unintentional, it’s going to be a disappointment.
Here’s an example of a challenging situation I faced in Minnesota’s North Woods along the Cascade River. The twisted roots of the tree are just a couple of feet from the lens but the waterfall is at least 100 yards away. But they are all in focus.
Cascade Falls (2011)
© by Ralph Nordstrom
Causes of Out of Focus Photographs and Their Cures
There are two primary causes of out of focus or improperly focused photographs. There may be insufficient depth of field or the wrong thing may have been what was focused on (wrong focal distance). Let’s take up focal distance first.
What you focus on is very important in determining what will be in focus and what will not. It’s possible to have a photograph where only part of it is in focus because you focused on the wrong object. Had you focused on the right object it would have all been in focus.
Your DSLR has an array of focusing points. When you photograph in auto-focus mode the camera decides which focusing points to use and therefore what to focus on; in other words, it determines the focal distance. And in most situations it does an excellent job. But sometimes it is fooled and it focuses on the wrong object. There are a couple of things you can do when this happens. You can override the camera’s selection of focusing points and tell it which focusing point to use. That way you can control your focal distance.
Of you can switch to manual focus and do it all yourself. With live view this becomes a very precise way to focus. You select the object you want to focus on and in live view you move the little rectangular viewing area over that object and increase the magnification to 10x. Now you can get a very precise focus on that object.
But how do you know what object to focus on? If you have a near/far composition in which you have a foreground, middle ground and background you want to focus on an object that is twice the distance to the closest object in your composition. For example, if the nearest object is 10 feet from your lens, you want to focus on an object that is 20 feet away. This is the most accurate method. But another method that works almost as well is, when viewing your composition in live view, select an object that is 1/3rd up from the bottom of the frame and focus on that. Now this requires a little bit of judgment. For example, if a tree trunk extending from the bottom to the top of your image was your closest object you wouldn’t focus on it but rather something behind it.
When doing macro photography the rule is different. Focus on the object itself that you are photographing. This applies to wildlife and outdoor portrait photography as well. In the case of wildlife and portraits you want to focus on the eyes. In this situation it’s OK if other elements within the frame are out of focus.
This leads to the second cause of images being out of focus – depth of field. Depth of field is that range in front of your camera from nearer to farther where objects within that range will be in focus and objects either in front of it or behind it will be out of focus. If we continue with the example above where in our composition the nearest object is 10 feet from the camera and the most distant object is at infinity, we said that the focal distance is twice the distance to the nearest object which is 20 feet. However, if the depth of field is too shallow the depth of field may only extend from 15 feet to, say, 200 feet. So anything closer than 15 feet or farther that 200 feet will be out of focus.
Depth of field is controlled by three variables, what I call the 3 F’s – the focal distance (which we have already discussed), the focal length of your lens and the f/stop. Normally the focal length of your lens will be determined by the composition as will the focal distance. So the only variable left to adjust the depth of field is the f/stop. The lower the f/stop the shallower the depth of field; the higher the f/stop the deeper the depth of field. I have another article that tells you how to calculate the f/stop you need for the appropriate depth of field so I won’t go into it here. Read Mastering Sharpness – Depth of Field.
Summing It All Up
I’ve mastered all of these skills and techniques and you can too. It takes a little practice but they’re not hard to perfect. So why do I still come home with fuzzy images? The answer is simple. I’m not always careful enough. I don’t slow down enough to make sure everything is right before I press the shutter. When I take the time to ensure every aspect is correct I get excellent images. But when I get into a rush there’s a chance that I’ll come home with fuzzy images. And the biggest culprit is depth of field.
So my advice to you is to also slow down. Make sure you have the correct depth of field for the image you are taking. When you do you will have mastered sharpness and no longer experience the disappointment that comes from discovering when you get home that photograph you were really excited about is fuzzy.
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