29 August 2009

When 2mm Is Big Deal

Returning my Canon SX10 and smashing my piggy bank, I've ordered a refurbished Canon 40D. I think it will work well for me.

I have a couple of decent lenses for it, from my film gear, but nothing spectacular. I have two prime lenses that, like most primes, are far sharper that any zoom for the same money. But I'd like a good zoom, and good zooms are very expensive. By "good" I do not mean a six-pound f1.2 IS DO XYZ mega-super-zoom, but just zooms that take sharp photos with good contrast. My bigger zooms are poor, but I don't care about big zooms anyway. What I need is a good all-purpose lens, a standard zoom, meaning standard wide-angle to mild-telephoto.

The basic zoom lens most everyone uses is a "kit lens," the lens that comes with most consumer DSLRs. My new 40D, being mid-range and a refurb, comes without a lens (one reason I could afford it). Only entry-level cameras come with kit lenses.  But the quality of kit lenses is a big deal for consumers, since it the only lens most people will ever use.

I have a couple of older kit lenses, including Canon's first DSLR kit lens, the (non-IS) EF-S 18-55mm (not sure if it is the mk I or mk II, but both are optically identical). While it gives you a modest wide angle zoom (28mm equiv.) for your small-sensor DSLR, this is not a good lens. However, the latest Canon kit lens (EF-S 18-55mm IS), which I do not own, is rated quite a bit better.

I do own an EF 28-105mm USM from my film days that is a modest step up from the old kit lenses, but it is only sharp stopped down to at least f5.6 and offers no wide angle on small-sensor DSLRs. So it is not really a standard zoom anyway.

The one decent standard zoom I "have the use of" (from work) is an EF-S 17-85mm IS USM, which at its introduction was a good (and not cheap) step-up lens. It has a longer zoom range than the basic kit lens as well as USM (= faster, quieter, and full-time manual focus). Optically it is a bit better, too, but not a lot. If optical quality is important to you, you really have to move even further up the ladder.

For Canon users, that has traditionally meant pro-grade L-series lenses. These are very expensive, mostly well north of $1000, and none are EF-S, meaning designed for small-sensor DSLRs. This means their wide end is not wide at all for cameras like mine. To fill this gap, Canon introduced the EF-S 17-55mm f2.8 IS USM. This is great lens, sharp and with a fast constant aperture that is the hallmark of pro lenses. But it's also a $1000 (street).

But Tuesday Canon will introduce a new SLR and at least three new lenses, two of which are EF-S for small-sensor DSLRs like mine. Details are already leaked, as well as MTF (optical performance) charts.

One is an EF-S 18-135mm IS (roughly 28-200mm equiv.) that edges into "compact superzoom" territory. Its performance does not look to be especially good, but most superzooms are optically poor, and the more super the worse. It will be another so-so step-up lens priced somewhere below the only current EF-S superzoom, the EF-S 18-200mm ($550 street).  Canon has actually droped the pricing info on the 18-200mm from their website. Maybe this new lens will replace that lemon.

The other lens is an EF-S 15-85mm f/3.5-5.6 IS USM. Even though the wide end is only 2mm wider than that of the 17-85mm, that still makes it 24mm equiv. Very few lenses, prime or zoom, go that wide. The only other Canon lens that wide is the EF-S 10-22mm ultra-wide zoom. It is expensive ($750 street) and, only 22mm on the long end, is definitely wide angle only.

The photographic difference between 15mm and 17/18mm (24mm and 28mm equiv.) is really huge. The difference in field of view is only ca. 8 degrees, but it looks and feels like a lot. Part of the reason for that is at 24mm you start to get some pronounced distortion effects at the edges that are absent from 28mm. You also get significant perspective distortion when close to your subject (great for silly dog photos, bad for serious people photos). Any wider and distortion careens into the realm of special effects.

This new EF-S 15-85mm will be a bomb of a lens, the perfect standard zoom for me and a lot of other people. The MTF charts (if accurate) make it a good performer and it will be priced for the prosumer rather than the pro (maybe $600-700 street). Not sure I'm really a prosumer, but I can (dimly) see one in my future . . .

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