Matt Bango Photography

As a photographer, whether it be nature, landscape, portrait, whatever, you always aspire for that “tack sharp” image. Sharpness is one of the image quality factors that can really make an image stand out and is one of the most closely related factors to the amount of detail captured and rendered in an image. In this article we’ll cover what sharpness is, how noise affects sharpness and some tried and true ways to make your images sharper, no matter what equipment you own.

If you talk to other photographers or on online photography forums, you’ll hear the term “sharpness” used a lot. You may be asking yourself, “Self, what exactly is sharpness?” Sharpness is basically how abrupt the boundaries are between different tones or colors. Let’s take a look at the following image. You can clearly see the difference between sharp and unsharp.

There are basically two factors that contribute to the perceived sharpness of an image, acutance and resolution. Acutance is illustrated in the image above. Acutance is all about the transition between edges. High acutance results in having clearly defined borders and nice sharp transitions and detail when an edge changes from one brightness level to another. This is why when “Unsharp Mask” is used inside Photoshop and the level is set to high, a “haloing” effect happens, in other words a white outline appears around certain parts in the image. Unsharp mask increases the acutance in an image. The other factor is resolution. Resolution describes the camera’s ability to distinguish between tightly spaced elements of detail. This is illustrated in the following image.

In the digital world, resolution is limited by your camera’s digital sensor. The level of acutance depends highly upon your lens and the type of post-processing you use. There are ways, in post-processing, that you can improve acutance. It can be enhanced digitally with the “Unsharp Mask” filter in Photoshop.

Now that we know resolution and acutance are the key players in sharpness, are there any other factors that play a role in the perceived sharpness of an image? Sure there are, a fairly big one that most people don’t understand is noise (or film grain). Typically most photographers think of noise as a factor that degrades an image. The truth is, small amounts of noise can actually increase the perceived appearance of sharpness. This is illustrated in the following image.

It is pretty clear to see how much sharper the image on the right looks rather than the image on the left. The only difference in the two images is the fact that the image on the left has almost no noise, and the image on the right has a small amount of noise. Noise is actually just tricking the eye into thinking sharp detail is in the image.

There is also another factor that I’ll briefly touch on. Viewing distance also plays a role in determining the perceived sharpness of an image. Large billboards or poster prints may be perceived to have the same sharpness as a 8×10 print of the same image, however they don’t actually have the same sharpness. This is because the resolution is different. The viewing distance of the billboard may be 100 feet away, so the resolution can be spread out, tricking your eye into looking exactly as sharp the 8×10 does at 2 feet away.

Now that we have a pretty good understanding of what image sharpness is and what affects it, how do you make your images sharper? There are many techniques and tricks you can do to improve your image sharpness. Any type of camera shake is going to degrade your image sharpness, so any reduction in vibrations or camera shake can increase the sharpness of an image substantially. More techniques and tricks are listed below.

• Use a Tripod. I cannot emphasize this enough. Proper camera support goes hand in hand with maximum sharpness and complete detail. A proper tripod is the best, but bean bags or any other type of support is better than nothing.
• If your camera has mirror lock-up, use it as much as possible. Using mirror-lockup will reduce the amount of vibrations that are created when making an image. Any reduction in vibration is always a good thing.
• Use manual focus. Believe it or not, even the latest greatest equipment can be off when auto focusing. Use manual focus to fine tune your auto focus and ensure your subject is at its maximum sharpness.
• Learn and know your equipment. If you have a zoom lens, learn the "sweet spot" in it. Learn which aperture of your lens produces the sharpest results.
• Use proper shutter speeds. If you are going to be hand holding your camera, make sure you have a fast enough shutter speed to eliminate camera shake and movements.

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