Blur: It's something that photographers of all skill levels battle from time to time, and there is not always an easy fix for it. Less than sharp photos are often undesirable, but the good news is that they can be cured. In today's article, we'll get to the bottom of blurry photos and look for the fixes.
Focus Issues
One of the most basic ways that you can end up with a blurry photo is to miss focus. The symptoms: something in the photo is sharp, but not what you wanted! (Or perhaps nothing in the photo is in focus)
There are a few things to check to cure the problem. First, if you are using an autofocus camera, make sure that autofocus is engaged. I can speak from experience that it's easy for the switch on the camera to be switched from autofocus to manual focus. Some cameras have switches to toggle auto to manual focus, and furthermore, some lenses have this same switch.
If your autofocus is in fact engaged and not behaving as you are expecting, it might be time to learn a little more about how your autofocus system works. Almost any camera, from point and shoot to SLR, has a variety of autofocus modes. Out of box, your camera is likely to come in a very "auto" form of autofocus, in which it will attempt to pick out your subject and then focus the lens to that subject.
Be careful not to bump this small switch on your lens, as well as your camera body.
If your camera is using this method and not getting the focus results that you desire, it might be time to learn more about your camera and how it can focus. Most cameras feature a variety of autofocus modes. When it comes to SLR's, the autofocus system usually works on a system of "points". In the most automatic of autofocus modes, the camera targets these autofocus points and attempts to select the one to use based upon the subject.
If you are looking to grow your skills with autofocus, it is possible to manually choose a autofocus point and point it at your subject matter. These types of modes take practice and revision, but can allow for superior results. Check out this article I recently wrote about some alternate focusing techniques to learn more about how many professionals choose to use autofocus systems.
Autofocus is a powerful system that has changed the way that photographers operate, but it is far from perfect. We can move toward improving our results by learning the way the autofocus system works, and exploring some of the advanced options of controlling it.
Shutter Speed
A slow shutter speed is another one of the most prevalent causes of blurry photos. Let's look at the two shutter speed issues that can cause soft, blurry photos.
First, let's take a look at what exactly shutter speed is. In almost any digital camera, the shutter opens to expose the sensor to light. The amount of time that the shutter opens to expose the sensor and create the photo is known as the shutter speed.
In this video, you can view in slow motion how a camera's shutter works. The shutter opens, exposing the sensor to light, and then closes to end the exposure.
The first shutter speed issue is choosing a shutter speed too slow for our hands. The idea here is that during the time that the sensor is exposed, we can't keep our hand still enough to prevent blurring the photo. The sensor needs to stay steady enough to keep the image sharp. If the camera shifts, so does the light that hits the sensor, and this causes blur.
There is a simple rule that can help us to obtain sharper photos and avoid this issue. Your hands may not be as steady as you think, so be sure to keep this rule in mind.
To utilize the rule, first consider the focal length of the lens that you are using. If you aren't familiar, this is the "length" or "zoom" of the lens. One of my favorite lenses is a 50mm lens. Zooms have a range of focal lengths, so note the focal length that you are currently using.
Now that you have noted a focal length, we can choose a shutter speed that will result in a sharp photo. This rule is 1 over the focal length. What does this mean? Go back to the example focal length of 50mm. Under this rule, our shutter speed should be 1/50th of a second. If we are at 100mm, choose 1/100th of a second.
This rule is not an absolute. Some people will find that they can choose a slightly slower shutter speed, while others will need to account for less steady hands. Any photography improvement requires practice and experimentation to find what works for you.
Remember also that a tripod can help you beat this rule! A nice, steady base overcomes the limitations that our hands have and will ensure sharp photos at practically any shutter speed. Choose a well-made tripod and you can shoot at any time of the day under practically any condition.
One more tool used to overcome the limitation of our hands is image stabilization or vibration reduction. Different manufacturers have different names for this technology. In short, optics within the lens shift in order to offset them movement of our hands to create an effectively sharp image. These can provide two to three stops of performance gain. Not every lens has IS/VR, so if this is something you want, make sure and purchase a lens with this integrated. Sony is notable for their system, which has "in-body" stabilization and stabilizes the sensor itself instead of using the lens to do it..
Subject Movement Blur
However, the other type of blur that results from shutter speed can't be overcome despite even the steadiest of hands or the best image stabilization. This type of blur is subject motion blur.
If the subject of our photo is moving, it makes little difference if our shutter speed is above the safe handholding speed threshold. Sports photographers will find themselves needing to use very fast shutter speeds, even if the camera is on a monopod or braced properly.
In this case, the sharpness of our photo depends on choosing a shutter speed fast enough to freeze action. We have to ensure we select a fast shutter speed (think 1/500th of a second or faster) in order to freeze action.
The blades of this ceiling fan appear blurred not because my hand was unsteady, but because the shutter stayed open long enough to capture a range of motion and appear as blur.
Other Causes of Blur
You nailed focus. You chose a good shutter speed. And still, your photos aren't as sharp as you would like for them to be. What could be the cause of this?
If you are still having issues with blurry photos, make sure that your lens is operating as it should be. This means checking the optics for anything that could be causing this drop in image quality. Make sure and check both the front and rear element and ensure that the glass is free from smudges, residue, or even worse, cracks or scratches.
One other autofocus issue is that with an SLR system, lenses and cameras don't always play nicely together. I have noticed this issue particularly with third party lenses, most notably Sigma. From copy to copy of the lens, the autofocus alignment can differ, and cause our images to miss that razor sharpness we often want.
We call this phenomenon "front focus" or "back focus", depending on direction that the focus tendency shifts. Advanced camera bodies have means to input a tendency and the camera will react accordingly, thus effectively negating the tendency of the selected lens. You can use tools like the LensAlign to calibrate your lenses. Also, sending in your camera with the lenses under warranty is a good way to get the lens calibrated.
For what my two cents is worth, although I do love some of my third party lenses, I find that they tend to have focus tendencies far more often than my name brand choices.
Embracing Blur
Since we've spent the entire article talking about how to eliminate blur, it might surprise you to find a section titled "embracing blur." I chose to discuss this because sometimes as photographers, we get too hung up on creating technically excellent photos and eliminating factors like blur that are considered undesirable.
The truth is that some great photos feature blur. Subject blur is a visual effect that conveys a sense of motion and can help the viewer feel action and direction within an image.
About a year ago, I made this photo by placing it on a tripod. The lights you see are an intentionally blurred subject - the headlights of cars passing by in a long exposure.
When making a photograph, I try to set goals; if my goal is to keep things sharp and technically excellent, it's important to know how to do that. However, blur has its place as a legitimate photo technique. Different situations call for different approaches - your editor at local a newspaper probably won't appreciate blur in shooting high school football games, but a fine art collector may laud your artistry.
Conclusion
Blur is one of the most commonly experienced effects that beginning photographers see. The problems and discussions above seek to help you solve and overcome blurry photos. However, remember that some types of blur has its place in art, and don't become so tangled up in technical talk that you miss the moment.
