By Joseph Kashi, for the Redoubt Reporter
Mandatory consumer warning: The following article is probably more incoherent than usual — it was written while a sugar-fueled teen Halloween slumber party was in full cry, complete with four teen girls, two enthusiastic and noisy German shepherds and a dachshund under foot.
Today’s article focuses upon interchangeable lenses for dSLR cameras. Yes, the pun’s intentional, but first let’s veer off-topic. As Emerson noted, “A foolish consistency is the hobgoblin of little minds.” Regular readers will undoubtedly vouch that I do not suffer from smallness of mind, at least as defined by Emerson.
Camera donations needed: Please call Joe Kashi, 398-0480, if you have any unused recent digital cameras that you would be willing to donate for a digital photography project at some of the Kenai Peninsula Borough School District’s more rural schools. Such a donation could be a useful tax write-off for you as the end of the year approaches. Digital Single Lens Reflex cameras and lenses, particularly Pentax dSLR bodies, would be particularly appreciated. We have a number of Pentax lenses already available.
Free and good
I’ve previously discussed Adobe’s PhotoShop Lightroom program as probably the most intuitive and effective photo-processing program on the market. The public trial “beta” version of next-generation Lightroom 3 can now be downloaded without charge from Adobe’s Web site at labs.adobe.com/technologies/lightroom3. Because this is a beta program, Adobe does not guarantee that it will work perfectly, although I have experienced no problems to date when using the 64-bit version of Lightroom 3 on Windows XP x64.
Adobe will periodically update the beta program, which will work until April 30, 2010, by which time the final commercial product should be shipping. Educators can buy an original copy of Lightroom from the Oregon Consortium for about $100, with extra licenses costing only $29 each.
Lightroom is becoming the standard for professional and high-end amateur photo processing that does not require the elaborate layering, editing and effects possible in Adobe PhotoShop. I find Lightroom to be a very powerful yet easy to use program. It’s certainly my own preferred approach to working with photo image files. Adobe Lightroom includes an excellent database to organize, view and choose images. Lightroom works with both ordinary JPEG and directly with the RAW format image files from over 250 different high-end camera models. Lightroom’s edits are nondestructive changes, which means that you can always revert to the original file as it came out of your camera without losing anything.
I heartily recommend Lightroom as your basic photo-editing program. Getting a free public beta test version of next-generation Lightroom 3 is the proverbial deal that you just can’t refuse.
Pat on the back
As you may recall from last week’s Redoubt Reporter, our recommendation for the best image quality and greatest versatility within a tight budget is the new 12MP Pentax K-X compact dSLR camera. Its image quality is noticeably superior to the output from the best small-sensor cameras, even those costing nearly as much. The Pentax K-X is one of the best, if not the best, entry-level dSLR cameras now on the market and uses the same, high-end, 12-MP sensor as some Leica cameras costing nearly four times as much. Your only real trade-off is a larger, though more versatile, camera.
We also recommended buying the upgraded Pentax 18-55 mm AL II kit zoom lens (NOT the all-plastic DA L kit lens that ordinarily ships with the K-X body) and buying the Tamron 70-300 mm Di LD telephoto zoom lens in a Pentax lens mount version.
Since our last issue, some internationally prominent photo Web sites in the U.S. and Britain have made the same recommendations in their reviews of the K-X and these lenses. Britain’s respected Photography Blog, for example, concluded their review of the Pentax K-X by awarding the K-X an almost unprecedented five stars for image quality and overall value, and their highest possible recommendation as “Essential” equipment, while Imaging Resource found that Pentax’s 18-55 mm DA II kit lens provided exceptional image quality for its low price.
The best value, for those who are both quality and cost conscious, would be to separately purchase a black Pentax K-X body and the Pentax 18-55 mm DA AL II lens (total of $714, plus shipping from Amazon), or the K-X body and Pentax’s higher end 16-45 mm f 4 lens from Amazon (total of $925, plus shipping). The Pentax 16-45 mm zoom lens is sharper over a wider zoom and aperture range, but the difference may not be worth the extra $210 to you. Adding the Tamron 70-300 mm Di LD telephoto zoom lens would increase cost by $155, plus shipping.
At the moment, Amazon seems to have the best prices and overall selection. Oh, yes — the K-X also does high-definition video, can shoot nearly five frames per second and includes many high-end features introduced last May in Pentax’s semipro K7 dSLR. Overall, the K-X is an excellently featured, low-cost dSLR camera built upon well-proven technology.
Interchangeable lenses
Typically, lenses made by brand-name cameras manufacturers, such as Nikon, Sony, Pentax or Canon, fit only cameras made by that manufacturer. Each vendor’s lens mount differs mechanically and electronically from the lens mounts for every other camera brand. Olympus and Panasonic are an exception. Their lenses have limited interchangeability, but with reduced functionality. Because Samsung’s current dSLR cameras are basically rebranded Pentax models, Samsung and Pentax dSLR lenses are likewise interchangeable.
There are three high-quality independent manufacturers, Tamron, Sigma and Tokina, who make complete lens lines for several different camera brands. It’s not uncommon for their lenses to be less expensive but at least as good as comparable models from brand-name camera manufacturers. Savvy purchasers will seriously consider the equivalent Tamron, Sigma or Tokina when shopping for a new lens.
Until a few years ago, the sharpness and overall image quality of zoom lenses was noticeably inferior to images made with single-magnification lenses. That’s changing. Some of the top zoom lenses now equal the image quality of superior, single focal-length lenses, for a price, while retaining the convenience of a variable magnification zoom lens.
There are several important factors to consider when choosing any lens, particularly a zoom lens. High resolution (sharpness) over the full range of magnifications and apertures is the most important criterion, of course, and poor lens resolution cannot be corrected with later software processing. If the detail is not present in the original image file, then there’s nothing to enhance and sharpen later.
Reducing unwanted internal reflections inside the lens is just as important as a lens’ sharpness. These reflections result from light bouncing back and forth between the various internal air-glass surfaces, a problem usually termed “flare.” Flare not only causes ghost images of bright objects like the sun, but reduces overall sharpness and the natural rendition of color.
Flare can be a serious problem with zoom lenses, whose more complex optical designs incorporate between 10 and 17 individual internal lenses, each of which increases the likelihood and severity of flare. There are several effective ways to reduce lens flair. In the first instance, try to avoid shooting directly into very bright light sources or reflections of them.
Be sure that you use the plastic, flower-petal shaped lens hoods that ship with your lens. It’s designed to reduce flare by shading a lens from bright objects like the sun that may not be visible in your viewfinder but that may catch the front of a lens and produce objectionable reflection. Lens hoods are not interchangeable — they are specifically designed for specific lenses to provide the best possible shading without blocking the corners at wider magnifications.
Finally, optical coating on each air-glass surface of every lens element helps a great deal, particularly when an advanced multicoating process is used. Advanced multicoating can make a real difference. For example, the Pentax and Tokina jointly designed their 12-24 mm ultrawide-angle zoom lens, and each brand uses exactly the same optical formula. Pentax, though, uses a more effective multiple optical coating in its version and, as a result, the Pentax version is generally considered to be superior.
Typically, consumer zoom lenses are sharpest when you shoot with an aperture that is one or two stops smaller than the maximum lens opening, i.e., shooting at f 5.6 or f 8 when the maximum aperture of your lens is f 2.8 or f 4. In addition, consumer zoom lenses are usually least sharp at their longest magnification settings and sharpest between their widest through midrange magnifications.
For best results, use the lowest feasible ISO setting and a high enough shutter speed to stop action and minimize camera shake. When using a slow shutter speed with any lens, particularly a telephoto zoom, either use a tripod or be sure that your camera/lens combination is stabilized to reduce the degradation used by camera shake at slow shutter speeds.
Next week, we’ll start our discussion of specific lenses by looking at telephoto zoom lenses in the 60 mm to 300 mm magnification range. A telephoto zoom is the most common lens purchased by consumers after acquiring an interchangeable lens camera.
Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. He has published many articles about computer technology, law practice and digital photography in national media since 1990. Many of his technology and photography articles can be accessed through his Web site, www.kashilaw.com.
