How to Get Pin-Sharp Photos: Advanced Techniques for Sharper Photos

Most commonly, blurry images are caused by either poor focus or the wrong shutter speed. Here is why that is so and what you can do about it.

In the last article, we discussed some factors that can make your photo blurry. Although all the issues mentioned there can and do cause blurry photos, most usually it is focusing incorrectly or selecting the wrong shutter speed that causes unsharp images.

Use the Correct Autofocus Mode

Most cameras come with different focusing modes. First is single autofocus (on most cameras, S-AF or AF-S. On Canons, it’s strangely called “One Shot”). It locks focus at a single distance when you half-press the shutter. That is perfect for landscapes.

Continuous Autofocus (usually C-AF or AF-C. But equally strangely on Canons, it’s called AI Servo) will continue moving the focus as the subject gets nearer or farther from the camera. It is great for, say, flying birds, toddling children, or even when the photographer is moving.

Clearly, if single autofocus is in use and either the subject or the photographer is moving, the focus can be lost during the interval between acquiring focus and releasing the shutter.

On the other hand, continuous autofocus on many cameras is rubbish for focusing on stationary subjects. The lens continuously hunts for focus, especially on most entry and mid-level cameras. Consequently, when you fully press the shutter button, there is a good chance you have missed the right focus distance. That said, cameras are getting better. With my cameras, for example, I can get away with shooting stationary objects in C-AF mode most of the time.

Some cameras have an automatic switching between single and continuous autofocus called AF-A (or AI Focus on Canon). However, this is less than ideal, and far more consistent results are obtained by selecting the correct focus mode for the circumstances.

Choose the Focal Points

Modern cameras can adjust the number of focus points they can engage, from one to all of them. My first DSLR had just three, quite close to the centre of the frame. My newest mirrorless camera has 1053, covering the entire frame. That makes accurate focusing far easier.

By default, most cameras will have all focus points selected. It will then focus on whatever is closest to the camera. That has its uses. When photographing flying birds, they are usually the nearest object. Therefore, selecting all points makes sense, especially when combined with focus tracking that follows the selected subject around the frame.

With a human portrait, a single focus point can be accurately aligned with the model’s eyeball. However, the camera may still misfocus and fix on the eyelashes instead. In that case, a small manual focus adjustment may be necessary.

Meanwhile, keeping a single autofocus point on a fast-moving animal is nigh-on impossible. Furthermore, there may be obstructions such as foliage in the shot closer to the camera. So, selecting all focus points won’t work either. In that case, a group of points may be more suitable.

A lot of that information goes out of the window if the camera has subject detection. In that case, the camera will recognise a face and either the left or right eye, and focus accurately on it. Alternatively, it can be set to detect birds, animals, planes, trains, and automobiles, and then focus on and track them as they move around the screen.

Focusing on the Wrong Place

The major cause of an unwanted blurry area in an image is the photographer focusing at the wrong distance. Many novice photographers are unaware that the depth of field varies depending on where they focus. Consequently, they are tempted to aim at the most obvious subject in the frame, such as a tree, an island, or a mountain.

The rule of thumb often touted for landscape photographers is to focus at a third of the way into the shot. However, that is just an approximation of the correct place to focus.

A far better approach is to use the hyperfocal distance (HFD). That is the point you focus on to achieve the maximum depth of field. It is affected by a range of factors. But, happily, there are apps to do the math for you. Probably the most well-known being PhotoPills. You enter the camera model, the lens focal length, and the aperture into the app. It will then tell you how close you can focus and still keep both the foreground and the infinity in focus, too. That is the HFD.

If you focus closer than the HFD, then infinity will fall out of focus. If you focus beyond it, then more of the foreground will be blurry.

Ignore the Math

How is the HFD calculated? It is a formula. You square the lens’s focal length. You then divide that by the f-number multiplied by the wonderfully named circle of confusion. You then add the focal length to it. The circle of confusion is the smallest blur spot a lens produces on a sensor or film when imaging what should be a single point. Pixel density, sensor size, display size, viewing distance, and human vision. Calculating the depth of field is even more complex.

But don’t get hung up on that. Just use the app to approximate the distance at which you should focus. I don’t know any photographers who carry a tape measure.

Choosing the Incorrect Depth of Field

Choosing the right focal point and the appropriate depth of field is important in other types of photography. Wildlife photographers often want the entire subject in focus while keeping the background blurred. Portrait photographers invariably want the subjects’ eyes to be pin-sharp. Then, subjectively, will decide how far back behind the face is also in focus. Do they want the ears sharp too?

The photo’s depth of field is governed by the aperture and, more importantly, the proximity to the subject. That is either the physical or optical closeness to the subject. The more you zoom in, the more the background will blur. Therefore, careful control of those factors is needed to achieve the right balance between in- and out-of-focus areas in the photo. For example, in the following shot, I wanted the entire gull that was closest to me to be in focus. However, I wanted to blur the background just enough so the other gulls were discernible, thus adding context to the image.

Shutter Speed and Sharpness

There are circumstances in which the camera can move during an exposure, not least because we are constantly moving and are not completely stable.

Historically, there was a rule of thumb that suggested that, if shooting handheld, your shutter speed should be faster than the reciprocal of the focal length. So, with a 50mm lens on my old 35mm film SLR, I would need 1/60th second or faster. Likewise, a 200mm lens would require 1/250th of a second or faster. Clearly, some people were more stable than others, and other factors, such as a strong wind, could also affect the minimum shutter speed necessary to take a photo without camera movement.

With modern cameras, things have changed. Over the last 10 years, two-thirds of interchangeable-lens cameras sold have been crop-frame, either APS-C or Micro Four Thirds. That is hard to believe, given that more marketing attention is given to full-frame cameras, but part of the reason is that they have higher profit margins. Full-frame pricing is based on what the market will bear, and professionals and high-spending enthusiasts are targeted.

Nevertheless, most readers are likely using a camera with a sensor smaller than 35mm. That changes the balance between focal length and stability, because the smaller frame exaggerates movement. For example, a 50mm lens may require more than 1/100th of a second on a Micro Four Thirds camera to keep the shot steady.

However, image stabilisation (IS) comes into play. My camera, for example, gives a whopping 8.5 stops of IS. That means, in theory, I can handhold a 50mm lens for 2.5 seconds. I have achieved that. Again, it is important to remember that some people are physically more stable than others.

It’s not just the camera that can move; the subject can, too. Everything travels at different speeds. Furthermore, subjects moving close to the camera will need a faster shutter speed to stop motion than those farther away. There is also the choice of whether to show movement or stop it entirely. You may want the rotating wheels of a car or the wings of a bird suggested by the photo’s blur, but have their forward motion stopped entirely.

In Conclusion

As you have seen from this and my previous article, there is much to consider if you want sharp images. That said, there’s no reason why you cannot celebrate blur too.