For every photo you take, it’s crucial to keep in mind one of four main factors that can lead to blurry images. Here, I’ll go over how to minimize each kind of blur in your photographs or prevent it altogether. Motion (from the camera or the subject), out-of-focus blur, diffraction, and lens aberrations are specifically the four causes of blurry photos.
Motion Blur and Camera Shake
Motion blur, which results from your subject or your camera moving too much while the photo is being taken, is possibly the single biggest cause of blurry photos. Only when an object in your photo moves across multiple pixels during your exposure will motion blur be visible.
The speed of the objects in your photo and how shaken your camera are both significant factors in this type of blur, but they’re not the only ones. Additionally, your shutter speed is crucial. You can capture sharp images of almost anything with a quick enough exposure. Even when photographing an animal or bird that is moving quickly, use a shutter speed of 1/1000 or 1/2000 seconds to avoid any blur at all:
This holds true for handheld blur as well. No one can hold a camera with their hands entirely motionless, but the movement brought on by your hands is manageable. To make sure you’re using a fast enough shutter speed, simply adhere to the handhold rule. Take extra precautions. Unless I have vibration reduction switched on, I personally prefer “1/(2 focal length)” instead of “1/(focal length)” when handholding my camera.
Technically, using a fast enough shutter speed is all that is required to get rid of motion blur—whether it comes from your subject or camera shake. For practically any photo, a 1/8000 second exposure will eliminate motion blur. The only problem, and it’s a significant one, is that quick shutter speeds result in darker pictures, and one of the central issues with photography is getting a picture that’s bright enough. If you’re going to take photos with a very quick shutter speed, you better have a means to make up for it and get a bright picture nonetheless.
In order to avoid motion blur, the ideal circumstance is to utilize a shutter speed that is just fast enough, or to take pictures that are so little that the quantity of motion blur is inconsequential. The sweet spot requires a lot of practice to find. Perhaps 1/100 of a second is the optimal shutter speed for a portrait shot, 1/500 for a sporting event, 1/2000 for a bird in flight, and so on. The only exception is when you’re using a strong tripod to take a picture of a still scene, in which case you can pretty much use any shutter speed without any issues. The same holds true if you intentionally blur a portion of your photo for impact.
Although your subject isn’t moving and you’re using a tripod, you can still experience some camera wobble. This is so because the camera itself contains moving components, particularly the mirror on a DSLR and the shutter curtain on the majority of cameras. These will generate tremors at particular shutter speeds that you can see in your pictures. The danger window is between 1/2 and 1/50 of a second, and telephoto lenses are more likely to pick it up.
If your camera has an electronic front-curtain shutter and mirror lockup mode, you can use these to reduce these sources of blur (or Exposure Delay mode on Nikon cameras). Another option to think about is a remote shutter release. These methods are covered in greater detail in our articles on shutter shock and taking sharp pictures with a tripod.
One more unrelated technique to reduce motion blur in a shot is to completely illuminate the scene using a flash. Most flashes have a relatively little duration, stopping the motion of even very rapid subjects like hummingbirds. However, you can’t fully illuminate every topic with flash, so this is far from an ideal solution.
Out-of-Focus Blur
Out-of-focus blur is the other primary cause of blur in photography. This one is available in a few various sizes and configurations.
On the one hand, just missing focus is the most straightforward instance of out-of-focus blur. Your subject isn’t absolutely sharp since you either focused a little too close or a little too far. In the worst circumstances, because your autofocus system was unable to latch onto anything, your subject may be drastically out of focus.
Take your time in the field and check that you have the proper subject in focus if you want to prevent this kind of blur. If you have time, enlarge live view to make sure your focus is spot-on. For example, focus on your subject’s eyes rather than their nose. The most important thing when capturing fast-moving objects, like sports, is practice. Learn exactly how your autofocus system operates, its advantages and disadvantages, and how to consistently lock onto your subject.
When your depth of field is insufficient, you can also get out-of-focus blur. Perhaps you are taking a picture of a group of individuals, and some are standing closer together than others. You can’t pay attention to both nearby and distant persons at once. Therefore, you must decide between the two, or if there is a suitable object for your autofocus mechanism to lock onto, try to focus at a distance between them. Even so, there will undoubtedly be some areas of your image that aren’t perfectly crisp.
This is a particular issue in landscape and macro photography, when you want the greatest depth of field possible to get your subject sharp throughout. In similar circumstances, you should usually accept a little blur in the background of the shot while focusing on the most crucial aspect of your subject. Additionally, you must utilize a narrower aperture to get a sufficient amount of depth of field.
This explains why f/8, f/11, and f/16 are commonly used by landscape photographers, and f/22 or smaller is occasionally used by macro photographers. It all depends on having adequate depth of field.
Even though it gives you more depth of field, you can’t always use a very small aperture, like f/22. On the one hand, apertures like this significantly darken your photographs; without a tripod or a flash, they become unusable. Beyond that, however, diffractional blur becomes increasingly apparent at small apertures.
Diffraction
Diffraction-related blur is less well-known than the other two types, yet it nevertheless has a significant impact on photography. A fundamental characteristic of all waves, including light, is diffraction. Light starts to interfere with itself as it passes through a wall or a hole, like the aperture in your lens. A pinpoint of light gets hazy as a result of the interference’s signal being stretched out. And a photo clearly captures that fuzz.
Although the physics of diffraction are outside the scope of this page, we do have a separate article on the topic. It’s crucial to understand that there is no getting around the fact that lower apertures result in more diffraction-induced blur.
Technically, diffraction occurs whenever light passes through an aperture, regardless of how big it is. However, unless the diffraction blur spans across several pixels, it doesn’t really matter. At apertures wider than roughly f/5.6 on today’s high-resolution DSLRs and mirrorless cameras, diffraction is difficult to see (though it still exists). Up until at least f/8, if not f/11, there is no impact. And diffraction doesn’t really start to affect image quality until you get beyond f/16 to particularly narrow apertures. To demonstrate how diffraction affects crops, consider the following comparison of 100 percent of the crops:
For the record, despite the diffraction-induced blur, I continue to frequently photograph at f/11 and f/16. They are two of my go-to apertures for landscape photography since the gain in depth of field frequently outweighs the trade-off in diffraction. But at high apertures, diffraction blur is apparent, therefore I like to shoot at or near f/8 when I can.
We have a sophisticated essay that demonstrates the aperture that, for any photograph, precisely balances depth of field and diffraction. But if you don’t want to get into it, the following advice ought to suffice:
- Don’t bother about diffraction at apertures wider than f/5.6.
- When you zoom in, diffraction is noticeable at apertures between f/6.3 and f/10, however it’s not horrifying.
- Diffraction is plainly noticeable at apertures between f/11 and f/16, but it won’t destroy a photo.
- If you don’t have a very specific need to, as for some types of macro photography, don’t utilize apertures from f/22 or higher.
Keep in mind that these numbers presuppose a full-frame camera sensor. To determine the corresponding range on your particular camera, divide by your crop factor. Large format 45 or 810 photographers use “crazy” apertures like f/64 for a reason.
What if, in the end, you find that you need an aperture as narrow as f/22 or even smaller to get adequate depth of field? Is it worthwhile to deal with the significant amounts of diffraction? Even while it might be important in some circumstances, try focusing stacking instead. Use a sharper aperture, such as f/8, and then shoot a sequence of pictures with the focus shifting from front to back, overlapping the depth of field in each picture. To create the sharpest image possible, combine the photos during post-processing. Only when your subject is stationary will this work.
Lens Aberrations
Lens aberrations, or blur merely because your lens isn’t sharp, are last on this list.
This one attracts a lot of attention in the field of photography, mainly because it is the only reason of blur that can be easily fixed by purchasing new tools. It is rarely the main reason for a fuzzy picture, though. Many times, people mistakenly believe that their lens is blurry when out-of-focus blur is actually the problem. In a landscape photograph, for instance, the front corners are frequently blurrier than the rest of the picture, but that is typically because they are out of focus.
Aberrations in the lenses still exist, though, and they can be important when using some lenses as opposed to others. Large apertures, such as f/1.4 to f/2.8, make them more noticeable, especially in the corners of the image. Lens aberrations (not only those influencing sharpness, but also things like vignetting) start to become extremely evident when shooting a particularly demanding subject, like Milky Way photography, where you’re at a high aperture but you want your corners to be crisp. Or, if your lens is especially fuzzy, you might detect substantial aberrations even at more common apertures like f/5.6 and f/8, with again more problems in the corners than the center.
Take a look at the two pictures below as an illustration. The Samyang 14mm f/2.8, a popular astrophotography lens with modest lens aberrations, is used in the first image. The second image was taken with the Nikon 14-24mm f/2.8 lens, which has less aberration and produces stars that are crisper and more pinpoint-like.
The good news is that since camera equipment alone causes lens aberrations, a wealth of information comparing lenses can be found online. Don’t get carried away here; a lens with low aberrations can only do so much to increase the overall sharpness of a picture. In all except the most extreme circumstances, like the one above, the differences won’t be noticeable unless you crop the image greatly.
However, it should now be clear why most lenses’ sharpest f-stops are typically in the region of f/4 to f/8. These apertures balance diffraction with lens aberrations, which are worse at wide apertures (worse at small apertures). Naturally, there are valid arguments for shooting outside that range in order to get the required depth of field. But these are the apertures you use if you’re taking pictures of brick walls, which are always in style.
Other Causes of Blurry Photos
Although the four elements mentioned above are the most significant ones, there are a few others that merit mentioning.
First, provided everything else is done correctly, a low-resolution photo will by default have less detail than one with many pixels. That isn’t precisely “blurry”; it’s more like “blocky,” but when you upsample the image to a bigger size, it can start to resemble blur. Most of the time, this is not a huge concern with today’s high-resolution cameras. The important fix is to avoid over-cropping your images because doing so could result in significant resolution loss. In a similar vein, avoid using JPEG as your file type (instead of RAW), particularly compressed JPEG, which removes data from a shot, including minute features.
Additionally, the ISO value you use affects the level of image detail. There will be a lot of noticeable noise in your photos taken in low-light conditions with a high ISO, especially in the shadows. This greatly obscures details; it’s not quite blur, but it’s clearly graininess. And further noise reduction during post-processing can result in a fuzzy or plasticky image.
Additionally, atmospheric distortion can cause blur when using supertelephoto lenses, especially when focusing farther away. This is particularly relevant to some distant wildlife photography and astrophotography of the night sky. It’s also one of the blur types that is hardest to correct. The best course of action is to either snap multiple shots in a sequence in the hopes of capturing one that is crisper or to wait till the atmospheric distortion lessens.
Last but not least, there are simpler ways to take blurry pictures, such using a dirty front lens element or piling a lot of cheap filters on top of each other. The same is true for lenses that purposefully produce fuzzy results, such as decentered lenses or soft-focus lenses. These instances might still be considered to be lens aberrations, but they stand out enough to be mentioned separately.
Conclusion
As you can see, there are numerous techniques to take fuzzy pictures. Nothing prevents you from breathing on your lens to make it foggy or intentionally adding blur in Photoshop if that floats your boat. However, if you want to prevent taking fuzzy pictures, you need focus on the following four major sources of blur: motion blur, missing focus, diffraction, and lens aberrations.
It’s impossible to totally eradicate all of these blur sources, let alone to a level that you would deem “acceptably sharp” in every situation. Often, eliminating one source of blur causes another to become permanently worse. As you progress to more technically difficult forms of photography, such as astrophotography or macro photography, this becomes increasingly difficult, and eventually even picture blending won’t be able to save the day.
That merely makes it even more crucial that you comprehend how to prevent these blur-causing factors and take the most precise pictures you possibly can. There is something you can do to take crisper images in practically any circumstance. Knowing the root causes of blur and how to reduce each of them is the first step in resolving the issue.
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