Another pattern common to the stratozooms is that their wide-angle extreme is uniformly 18mm. The effect of this 18mm itself is not uniform, some of the DSLR bodies having a slightly different cropping factor than others. Olympus lenses have a 2x factor-a "normal lens" with a "50mm equivalency" is 25mm by FourThirds specs. Other cameras introduce smaller factors, usually under 1.5. In other words, an 18mm zoom setting on a FourThirds camera will have an "equivalency" of a 36mm zoom setting on a 35mm camera. An 18mm zoom setting on other DSLR bodies will come to an "equivalency" in the realm of 28mm or so.
A wide-angle extreme of 28mm or so is healthy, plenty for most of the settings of ordinary life. But of course, it's the extraordinary settings of life that Joe Foto photographs, and happily a "28mm equivalency" is far from being the sole choice before him.
THE SHORT VIEW
Canon and Nikon both produce wide-angle zooms that reach down to what used to be called "fisheye"-before it became approximately rectilinear. Canon's widest zoom is a 16-35mm, Nikon's is a 12-24mm (DX format) and 14-24mm (full-frame). Sony chimes-in with an 11-18mm.
Pentax has a distinctive piece in their 10-17mm, technically a fisheye but capable of pictures that look almost rectilinear. The next-widest Pentax, with more of a standard perspective, is their 12-24mm.
Yet in sheer volume of lenses with an angle-of-view wider than the once-very-wide 24mm, the trophy goes to FourThirds, mostly Olympus. Their widest is a 7-14mm, a spectacular performer as we recall it, followed by an 11-22mm. Intriguingly, their next-widest is the 12-60mm that was introduced along with the E-3 as that camera's de facto "standard." That's a 24-120mm "equivalent" "standard." with an f/2.8 maximum aperture-barely a 5x range, but pretty good as a "universal" lens might go.
Only one other of the manufacturers mentioned provides as many ultrawide zooms as Olympus does, and that's Sigma again-with a 10-20mm, a 12-24mm, and a 15-30mm (which we are told is being phased out). However, since the 10-20mm is available in a FourThirds mount, it gives cameras using that standard (Panasonic Lumix L-1 and L-10, and Leica Digilux 3 in addition to Olympus DSLRs) the largest collection of superwide zooms to choose from.
THE FAST VIEW
When it comes to low-light shooting capability, however, the champ is who you'd expect it to be -Canon. The company lists two lenses that open-up to f/1.2 (both non-zooms, a 50mm and an 85mm).
The numbers are so close that you wouldn't think an f/1.2 lens lets-in half-again as much light as an f/1.4. The aforementioned Canon lenses appear to be the fastest lenses currently available for use on DSLRs (APS and full-frame sensor models), followed-up by an f/1.4 at 50mm.
The f/1.4 specification is where we find more of the industry awakening to the needs of low-light photographers. Nikon's fastest current offering appears to be an 85mm f/1.4. Pentax produces a 50mm f/1.4. Sigma recently announced a 50mm f/1.4, perhaps as a companion to their existing 30mm f/1.4.
The line with the largest selection of f/1.4 lenses appears to be the Zeiss models in Sony (Minolta) mounts, of which there are three: 35mm, 50mm, and 85mm.
It is, of course, easier to make a superfast non-zoom lens than a superfast zoom, and a superfast wide-angle than a superfast tele (making Canon's f/1.2 85mm remarkable in the field). When we get to zooms, the fastest appears to be f/2-and here the honors go to Olympus again, for their new 14-35mm (a 28-70mm "equivalent," still very wide-anglish) and 35-100mm lenses. Nikon is the runner-up with one f/2 zoom on their list, a 200-400mm.
THE long VIEW
When it comes to telezooms, the longest seems to be a Sigma again, their f/2.8 300-800mm. A maximum aperture of f/2.8 is very impressive for this tele range, and the price of the lens is barely over one-third of the 200-500 we opened with.
After that Sigma, the telezooms generally top-off at 500mm. Tamron produces a 200-500mm f/5.6-6.3, and the Olympus 70-300mm (whose telephoto extreme has an "equivalency" of 600mm, or about as long a zoom lens as you'll find on today's market). The Sigma 300-800mm comes in a FourThirds mount, giving compatible cameras perhaps the longs telezoom yet-a 1600mm "equivalent." Next comes the aforementioned Nikon 400mm, followed by several models that cap at 300mm-the Canon 28-300mm, and a Tamron 28-300.
Everyone provides a Stratozoom lens with a 10x range or higher, but it should be obvious that these aren't quite the "universal" lenses they might at first be thought. And if your Joe Foto has particular needs, he might be surprised by the brands that answer them best.
Low-light shooting? Canon takes the trophy there, with their f/1.2 lenses. But when it comes to f/1.4, Sony seems to have the broadest selection of non-zooms. Olympus has the fastest zoom at f/2, and the most expansive range of focal lengths you can get-from 7mm (14mm "equivalent") on the wide-angle end to 800 (1600mm "equivalent") through a Sigma zoom (and 300mm under the Olympus brand).
In the examples cited, we've given a few indications of how one make of cameras or another might be preferred by your friendly, neighborhood Joe Foto, depending on whether he faces extra-demanding conditions (such as very low light, or very distant subjects). We could say more about lenses, and undoubtedly will in future issues, that less clearly define a camera brand as "best" at any one activity, but which distinguish the line anyway.
We're thinking of the recently introduced Pentax f/2.8 50-135mm zoom. It's pretty fast, and has a good medium-telephoto range. There aren't too many lenses like it on the present market (Nikon's AF-S D 55-200mm could be considered generally comparable in focal-length range, but with an f/4-5.6 maximum aperture it needs much more light. It has greater need for the Nikon VR image-stabilization system that it comes with, whereas the Pentax lens, even though faster, is automatically image-stabilized because all Pentax DSLR bodies now have the feature built-in.
Ultimately, the most satisfactory camera system for a given user involves a combination of optical and mechanical features built into the lenses and the bodies both. But there are times when the optical specs alone will make the clincher, and you and the customer will have to dig-into all the numbers that come attached to them. It's hardly a new principle, but the optics for digital SLRs are becoming diverse enough that purchasing decisions are legitimately based on lenses for a change.
Don Sutherland has sold cameras across the counter, shot with them as a pro, and written about them for more than 30 years. Don is a photo historian as well as a futurist, and is the author of the immortal slogan, "If you have one foot in the future and one in the past, you understand the present perfectly." Email Don at firstname.lastname@example.org. Go to www.don-sutherland.com for a ton of digital photos.