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Categorized | Articles, Paul Burwell

Digital Chat — Insatiable Desire for Sharpness (full story)

Sharp images. It’s one of those things that many photographers crave and are almost addicted to. When I encounter photographers obsessing about sharpness, I’m reminded of this quote from legendary photojournalist Henri Cartier-Bresson: “I am constantly amused by the notion that some people have about photographic technique–a notion which reveals itself in an insatiable craving for sharpness of images. Is this the passion of an obsession? Or do these people hope, by this trompe l’oeil technique, to get to closer grips with reality?” So in an attempt to get a closer grip on reality, I’ll talk about what sharpness in digital photography is really all about and a new tool that can help those of you craving more of it.

©Paul Burwell Image illustrating the effect of sharpening (a.k.a increase in acutance)

©Paul Burwell
Image illustrating the effect of sharpening (a.k.a increase in acutance)

When we talk about sharpness, what we’re usually talking about are two different things that affect our perception of sharpness. The first factor that affects our perception of sharpness is resolution, or the ability to distinguish fine detail in an image. The resolution of your images is determined at the instant the photo is made and is influenced by your camera’s sensor and the quality of lens you used. Unlike what some popular television crime scene shows will try to tell you, if the camera didn’t capture detail in the first place, no amount of massaging the image by a computer can render detail that was never recorded in the first place.

The second factor that affects our perception of sharpness, and perhaps your brand new word for the day, is something called acutance. This is a term that describes how quickly tones transition at an edge. High acutance results in sharper appearing transitions and detail with clearly defined borders. So when you bring your photo into software (Photoshop, Lightroom, iPhoto, Aperture, etc.) and ask it to sharpen your image, what you’re really doing is asking it to increase the acutance of the image. Of course, many different programs and techniques have been developed for sharpening images over time, but at their essence, what they all really do is enhance the acutance. I’ve created a simple graphic to illustrate what sharpening really does when it enhances acutance. It looks for tones that are next to each other and slightly darkens the darker tone and brightens the brighter tone, thereby making it appear that the transition happens more suddenly.

Enhancing acutance is the one aspect of sharpness that you have control of after you’ve made the image. Technique and equipment both impact how much acutance your images have. Technique you can master with practise, but equipment is another matter. Some lenses just don’t give great results at some settings or are just poor copies to start with. That’s why when I came across a piece of software called Piccure+ that promises to help the sharpness of images affected by technique or the lens itself, I was intrigued.

You can run Piccure+ as either a plug-in for Photoshop or Lightroom, or as a stand-alone program. When you run it as a stand-alone program, you can send it batches of images in RAW, TIFF or JPEG format. When it starts you’re presented with a nice, clean interface, whether you run it as a stand-alone program or as a plug-in. You have controls to modify the magnification of the image you’re viewing, the ability to preview before/after versions and controls for the sharpening itself.

The first decision is whether you’re correcting for lens sharpness issues or motion sharpness issues. If it’s a lens issue, by using the Speed vs. Quality slider you decide if it’s important that the image be sharpened quickly or well or somewhere in between. If the image is exhibiting signs of chromatic aberration (a type of lens distortion causing shapes to exhibit a fringe of colour), you can correct for that with the Optical Aberrations slider. The Sharpness slider lets you choose between Smooth on the low end and Sharp on the high end. A De-Noise option allows for some noise reduction to be applied to the image because as you sharpen an image you’ll introduce and or increase the amount of noise in the image.

Once those sliders are adjusted to your liking, you can choose to Preview the results (to save processing time). If you like what you see you can choose to process and then save the results. Otherwise, work with the sliders to get the results you’re looking for. It should be noted though that you can’t take something that’s completely blurry and make it totally sharp looking. If those are your expectations you’ll have to be more realistic. The image of the tree swallow suffers from a lack of sharpness due to my use of the lens with the aperture wide open at f5.6, and the particular lens I used not performing well at that setting. You’ll see that Piccure+ did a great job of adding back some sharpness.

©Paul Burwell Tree swallow Gear/Settings: Original Canon Digital Rebel, Canon 100-400 f/4.5-5.6L IS shot at 400mm, ƒ5.6@1/640 sec., ISO 100

©Paul Burwell
Tree swallow
Gear/Settings: Original Canon Digital Rebel, Canon 100-400 f/4.5-5.6L IS shot at 400mm, ƒ5.6@1/640 sec., ISO 100

If, on the other hand, it’s motion that’s affecting the sharpness of your image, change the mode selector from Lens+ to Motion+. This will cause the Optical Aberration slider to be replaced with a Camera Shake Intensity slider and you’ll be able to choose between Micro, Medium or Large motions (or somewhere in between). Again, if your shutter speed was just way too slow and you’ve ended up with a blurry mess, nothing, including Piccure+, will help you. But, as you can see in the photo of the Grizzly, the Piccure+ has managed to recover some important detail on the bear’s face that was previously blurry due to a slow shutter speed and the bear moving its head.

©Paul Burwell Grizzly bear Gear/Settings: Canon 1Ds Mark II, Canon 100-400 f/4.5-5.6L IS shot at 400mm, ƒ5.6@1/200 sec., ISO 800

©Paul Burwell
Grizzly bear
Gear/Settings: Canon 1Ds Mark II, Canon 100-400 f/4.5-5.6L IS shot at 400mm, ƒ5.6@1/200 sec., ISO 800

Overall, I found Piccure+ an excellent tool for those of you craving “a greater grip on reality.”  It was able to enhance a number of images in my collection that I’d abandoned because the results I could obtain through Photoshop or Lightroom just didn’t live up to my expectations. You can download a free 14-day trial from their website at piccureplus.com and if you decide to purchase it (through their website as well), it will cost you $119. It’s a bit expensive in my opinion, but if you have some images in need of sharpening, it just might be the tool for you. I rate it four stars out of five.

To read more of Paul Burwell’s columns and other great how-to articles please pick up the Winter 2015 issue of OPC today, or subscribe!

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