Why aren't your photos sharp enough?

For novice photographers, we are always worried that the photos we take are not "sharp". For Mr. Liu, there are always a lot of problems when looking at other people's photos, and one of the problems that will definitely be raised is not "sharp". For all people with obsessive-compulsive disorder in the later stage, they always keep sharpening in the later stage, just hoping that their photos look sharp enough.

But what is "sharp"? Why do we always feel that our photos are not sharp enough? How can I take sharp photos?

You think your photos are not "sharp" enough, probably because you made the following mistakes.

1, focusing is not allowed.

Don't laugh, this is really the most common mistake, especially now that we have given the camera the initiative to focus, the camera's autofocus system does not always meet our needs perfectly, and "out of focus" is also common when taking pictures.

Many times, the shooting effect we see on the LCD seems to be quite good, but once magnified, it feels not sharp enough. It still depends on what your needs are. If you really need to print oversized photos, the pursuit of detail is definitely essential. But if you just look at the photos on the screen or print small-sized photos, you don't need to enlarge them infinitely. It's actually ok to look at them.

2. The aperture is too big

Aperture will affect the depth of field. If the aperture is too large, the depth of field will be too shallow and the focus will be too small. The farther away from the focal plane, the more blurred the elements are. And if your subject is in a wide area, too large aperture will definitely make some parts of the subject out of focus.

Just like the cat below, because the aperture is too large, only the left eye is in focus and the right face is out of focus, which leads to blur. Look at the blur of the right ear.

However, it should be noted that the depth of field is not necessarily too large, because the control of depth of field is not determined by one factor of aperture, but also by distance and focal length. That is to say, if the distance and focal length are appropriate, even if the aperture is larger, it is possible to surround the whole subject in focus.

3. The aperture is too small

A large aperture will lead to a shallow depth of field. Is the aperture as small as possible? No, I said in an article before that every lens has its best imaging aperture. Above or below this aperture, the image quality will be degraded. However, too small aperture (different lenses will be different, generally below f/ 16) will produce diffractive optical phenomena. The direct consequence of this optical phenomenon is that the image quality will decline, the surface will begin to blur, and the sharp focus can not be found.

Although you don't need to deliberately take pictures according to the best aperture, you should try to avoid diffraction scenes when shooting landscape photography, which is why landscape photographers add ND filters in front of the camera instead of narrowing the aperture to extend the exposure time.

4, unnecessary shaking

When taking pictures, we always think of the safety shutter. Generally speaking, the reciprocal of the focal length of a lens is the safe shutter value of this lens, which means that we can avoid hand shock as much as possible above this shutter. For example, if we use a 50mm lens, the safety shutter should be above 1/50s, and if we use a 200mm lens, the shutter speed must be higher than 1/200s.

However, the safety shutter is only a theoretical value, and the specific use situation still varies from person to person. Some people may have iron hands and won't shake with a low-speed shutter, while some people are born with bad nerves and always shake. This involuntary hand shake will cause unnecessary jitter at the moment when the shutter is pressed, and it will also make the picture appear dynamic blur.

In addition, not only the safety shutter, but also the slight shaking of the subject will cause dynamic blur, so try not to use a low-speed shutter when shooting moving objects, such as portraits or animals.

5. The quality of lens or filter is too poor.

It makes sense that those high-end lenses are so expensive. Their optical design and the quality of lens materials must have been tested and polished countless times. In order to control the cost, of course, there will be less exquisite lenses, so those entry-level lenses or some cheap lenses may not produce such high quality, especially when the aperture is large, and the quality of focusing on the edge of the subject may be unacceptable. We say that some cheap lenses are good, most of which are relative to the cost performance. It is very good that this price can achieve such an effect.

Of course, I still want to say that the so-called high image quality still varies from person to person. Some people pursue high, thinking that it can't meet their own requirements, but it may be enough for most people.

It's not just the lens. We may sometimes use filters to protect the lens, but some cheap filters will definitely affect the image quality. If you use a cheap filter and feel that the lens effect is not good, you may wish to take off the filter and have a look. Maybe the problem really lies in the filter.