Bad News. The most common reason for blurry images is not a broken or bad camera. You are the reason!
Good News. It’s easier to fix than you might think!
Here’s the 10 most deadly reasons for blurry images:
1. ISO Setting
The ISO setting determines how much light your camera setting can capture in a given time frame. Your camera can capture more light with a high ISO number than it can with a low ISO number. And now to the important part, the amount of light the camera sensor can capture determines the shutter speed and a slow shutter speed is the most common reason for blurry images.
Let’s take a look at the relationship between ISO, shutter speed and image blur.
Low ISO => Slower shutter speed => Increased risk for blur
High ISO => Faster shutter speed => Reduced risk for blur
Low ISO setting in combination with low light and a small aperture exaggerates the problem as you soon will see.
2. Aperture Setting
The aperture determines the mount of light passes through the lens in a given time frame. A large aperture allows more light to pass through the lens and a small aperture will only allow a small amount of light pass through the lens. This means that the shutter speed must be longer with a small aperture opening.
The relationship between aperture, shutter speed and image blur is.
Small aperture => Slower shutter speed => Increased risk for blur
Large aperture => Faster shutter speed => Reduced risk for blur
A small aperture in combination with low ISO setting and low light exaggerates the risk for image blur.
3. Low light
The shutter naturally needs to stay open longer in a low light situation to be able to capture enough light for the exposure and this leads to increased risk for blurry images.
Low light => Slower shutter speed => Increased risk for image blur
Strong light => Faster shutter speed => Reduced risk for image blur
Again, low light in combination with a low ISO setting and a small aperture exaggerates the risk for image blur even further.
Another common problem with low light is that your camera might have problem to auto focus in low light and this naturally leads to unsharp images. It’s also very difficult to focus manually in low light situations.
4. Mirror vibrations
A DSLR with exchangeable lenses contains a mirror that flips up when you press the shutter and this can cause vibrations in the camera leading to image blur. This phenomenon is only visible for certain shutter speeds and is not a problem for very slow and very long shutter speeds. It’s not a problem with a pocket camera either as they don’t have a mirror.
This is mostly a problem in “mid range” shutter speeds around 1 second to 1/120’s of a second.
5. Moving subject
A fast moving subject like a speeding car and a running dog often cause blurry images but image blur due to moving subjects only affects the moving subject itself while the other parts of the image is sharp. This in contrast to most other image blur that causes the whole image to be unsharp. A fast moving subject in combination with a slow shutter speed exaggerates the problem further.
The best thing you can do to prevent image blur caused by moving subjects is to increase the shutter speed until it freezes the subject. Faster shutter speed can be obtained with higher ISO setting and a larger aperture.
6. Focal length
A long focal length exaggerates camera shake and consequently the risk for image blur substantially.
Long focal length => Increased risk for blur
Short focal length => Reduced risk for blur
You can as a good rule of thumb assume that with a X mm lens is the slowest shutter speed you can use 1/X of a second. For instance
- With a 35mm lens is the slowest shutter speed 1/35 of a second
- With a 200mm lens is the slowest shutter speed 1/200 of a second
This rule of thumb is only applicable for hand held cameras with no Image Stabilization. With a tripod you can leave the shutter open for minutes and sometimes even hours without blur.
7. Camera shake
You will almost certainly get image blur if the camera moves slightly when you press the shutter button. Keep the camera still and don’t move it until after you released the shutter button completely. It’s best to wait about 1 second after you release the shutter button before you move the camera.
A bad tripod, especially under windy conditions and with a long focal length is also a common reason for image blur. A small light tripod is very vulnerable for this kind of problem and you’d be surprised how much a bad tripod can vibrate even though it seems like it’s stable.
8. Camera handling
Most photographers like to blame the camera when they get blurry images but the truth is – it’s more often than not t?he photographer causing the problem in the first place. Let’s be honest; have you read the instruction book and really understand how the camera works? Most camera owners have not.
Most cameras have small areas in the viewfinder that are designated for focusing. In some cameras you can see the areas in the viewfinder and which area the camera selected to focus the image on. This is invisible in some cameras so you won’t know exactly where the camera focused.
The result is often that the camera focus on the wrong subject causing aunt Molly to be blurry and the Christmas tree in perfect focus.
Many cameras have different focusing modes for different situations, especially for fast moving subjects. You will make it easier for the camera to focus if you selects the right focusing mode.
9. In camera sharpening
In most digital cameras you can set how much sharpening you want it to do when it creates the image file. No, sharper is not always better in this case and most professional photographers set the in-camera sharpening to a low value or even turn it off completely. Then they sharpen the images in their image editing software afterward.
The reason is that this kind of “unsharpness” is not the same as a blurry image caused by the other problems in this article. Seemingly unsharp images caused by low in-camera sharpening is in fact not a problem at all.
The camera will not use any in-camera sharpening at all if you use RAW file format so these images will often look very soft before sharpening is applied.
10. Broken camera
Many photographers blames the camera for their blurry images but it’s in reality the other reasons listed in this article causing the problem most of the time.
Nevertheless, a faulty camera or bad lens can be the root of blurry images so if you tried everything else in this article and nothing works you might need to repair or get a new camera or lens.
