What Does It Mean for a Photo to be “Sharp?”

Author: Harry Guinness / Source: How-To Geek

In photography, we strive to take “sharp” photos. Generally, this means that you want the subject to be in focus with clear lines, crisp details, and no (unintended) blurring. It’s a combination of accurate focus, a static camera, and the properties of the lens you’re using.

One thing to note is that there are two kinds of sharpness: there’s an official optical measure (it’s called acutance) that gets all kinds of complicated fast, and there’s perceived sharpness, which is what photographers mostly want. We’re tackling the latter one today, although there is some overlap with optical sharpness.

So, let’s dig in.

What is Sharpness Anyway?

As defined above, a sharp image is one where the subject of the image—or the bits of the subject you want—are in perfect focus with every detail crisp and clean. Below, is one of my favorite examples of this.

The main “subject” of the photo is Kat’s eyes; they’re so sharp you can see the individual eyelashes even though the focus fades off across her face. Just compare the sharpness of her eyes to the slight blur of her ears and the indistinct background. I know I’m tooting my own horn, but it’s a pretty great example of the classic “portrait look.”

Let’s look at another example, this time from landscapes.

Here the image is sharp throughout the frame, from the rocks in the foreground to the lighthouse in the background. The motion blur in the rocks is just an element of long exposure photography.

In both examples above, the sharpness is a result of accurate focus, a static camera, and the lens and its settings.

Let’s take them one by one.