By Joe Kashi, for the Redoubt Reporter
It’s nearly axiomatic that the resolution of photographic tools constantly increases, with some cellphone cameras claiming an astonishing 41 megapixels, but it’s not a free ride. As photo resolution increases, so do potential pitfalls.
With some knowledge and discipline, these problems are readily avoidable. This week, we’ll consider a few basic practices whose importance becomes more evident as resolution increases. These tips are just as useful for users of cellphone and basic cameras as for persons using more advanced photographic tools, perhaps more so because cellphones and basic cameras don’t have as much technical leeway to compensate for sloppy technique.
It’s worth remembering that digital photography generally provides a higher level of image quality with less hassle than traditional film photography. During the film era, it was difficult to produce an excellent quality, 11-by-14-inch color print from 35-mm film or a technically excellent print larger than 16-by-20-inches with a large-format view camera.
Now, even consumer-grade, interchangeable-lens digital cameras are quite adequate for most professional requirements, easily exceeding the quality of film photography and early digital photography. These technical advances encourage modern users to make much larger prints than prior practice and to project their images onto giant TV screens.
So, in a sense, our expectations have risen. The question is no longer whether midlevel photo gear can handle most challenges. Rather, how can most photographers best use current photo gear to benefit from higher resolution. That’s where a bit of personal knowledge and discipline enter.
Luckily, digital photography makes experimenting and learning far less expensive and much more immediate. Unlike chemical film processing and printing, electrons are virtually free and there’s immediate feedback on the camera’s LCD screen about whether your shots work, not the several-day turnaround expected when developing and printing film.
As resolutions increase on the same-sized sensors, though, several problems often become more evident. Lenses that previously seemed good enough optically start showing their limitations. Blurring due to imperfect focus, reduced depth of field and camera shake becomes more common. Shadow and highlight areas exhibit less detail and lower tonal quality due to reduced dynamic range. Noise increases while high-ISO situations require more careful attention.
I’m sure that other problems occur, as well, but these are the ones I’ve experienced most often as I moved to increasingly higher-resolution cameras. I’ve even noticed concerns when I moved from the 16-megapixel Pentax K-5 dSLR to its successor, Pentax’s 24-megapixel K-3, a top-rated prograde model that also uses well-proven Sony sensors.
The sole exception to this doleful progression occurred when I upgraded my Micro Four-Thirds camera to the then-new Olympus OM-D E-M5. The OM-D’s new 16-megapixel Sony sensor was a major improvement over earlier 12-megapixel sensors, providing better high-ISO operation, lower noise, better sharpness and faster shutter speeds. That new Sony sensor incorporated enough new technology that it solved many former limitations. So, perhaps one frugal solution is to wait a few years for the next technical leap. That doesn’t help you take pictures of family, wildlife, sports or landscapes in the meantime.
Inevitably, if you want to benefit from buying those extra megapixels, then you’ll need to be more careful about balancing and trading off competing technical issues. As our example this week, let’s consider how blurring due to camera shake might be adversely affected. In some ways, camera shake due to too-slow shutter speeds was one of the easiest problems to avoid.
Previously, we’d compensate for camera shake by simply using a faster shutter speed appropriate to the magnification of the lens in use. Doing so required either increasing the ISO sensitivity setting or using a brighter lens aperture. Image-stabilization hardware certainly helped avoid camera-shake blurring but my sense is that the pixel-level effectiveness of image-stabilization hardware is adversely affected by smaller pixels.
Higher-megapixel resolutions are achieved by packing more, but smaller, pixels into the same sensor area. Unless a particular sensor also includes major technical improvements, smaller pixels and higher pixel density means degraded high-ISO performance and increased digital noise that may limit any theoretical resolution gain. Dynamic range also decreases.
If we instead use a wider, brighter lens aperture, then optical imperfections become more evident at those wider apertures, even among better lenses. Depth of field is greatly reduced, complicating focus. And unless the sharpness of your lenses exceeded the capabilities of your old, lower-resolution sensor, you’ll not see any increased sharpness by using those same lenses with a higher-megapixel sensor. Indeed, you might even see a decrease in sharpness with middling-quality lenses that now smear image details over a width of several pixels.
Although increasing ISO sensitivity and using a brighter lens opening may be needed in many solutions, neither is a complete solution to camera shake and blurring.
Using a tripod and the delayed shutter release timer is the best option with relatively static subjects that require the great sharpness and depth of field achievable by using a relatively small lens aperture and a low ISO sensitivity setting. The only effective solution here is a very long shutter opening time, beyond the ability of most people to hand-hold the camera without a great deal of shake and blur.
When photographing fast-moving sports, like football or hockey, or perhaps wildlife in the field, a tripod is often too bulky and slow. Here, a good monopod is usually the camera support of choice among knowledgeable sports and wildlife photographers. A monopod often provides enough additional stability to allow the use of the slower shutter speed or smaller lens opening when needed.
Using a camera that includes an eye-level viewfinder is another useful approach to reducing camera shake and blur, especially when using telephoto lenses that further magnify any shake and blur. The eye-level viewfinder provides a more stable point of contact with your forehead and thus a steadier support than merely holding a camera in front of you with two hands while viewing the rear LCD screen. You’ll also significantly improve the steadiness of your shots by bracing yourself against something solid when shooting at slower shutter speeds.
Next week, we’ll consider how to get the most out of your existing lenses, when to upgrade your optics and where to find important information about your lenses. However, unless you first avoid camera shake and blur, the best lenses in the world will perform no better than the least-expensive kit lens.
Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. Many of his technology and photography articles can be accessed through his website, http://www.kashilaw.com.