Thursday, June 29, 2006

The Pentax SMC-P DA J 16-45mm And The Sigma 17-70mm DC Macro

Zoom lenses designed for the APS-C are the fashion accessory for the beach this summer, especially those that are light and not so soft on the outside. Of two popular hot picks, one's fun and willing to go fast and far, and the other is slim, sharp and consistent. The Lovin' Spoonful:"Did you ever have to make up your mind?"

When the Sigma 17-70mm F/2.8-F/4.5 DC Macro zoom lens was announced back in January, a few whisperers were worried that it was possible that the new lens might suffer from some of the softness, distortion and vignetting issues found in its siblings, the Sigma 18mm-125mm and the 18-50mm DC EX F/2.8. Would it even be worthy to compete with the Pentax DA 16-45mm ED AL F/4, as both would be in a similar price range? The Sigma boasts a farther reach, faster wide angle aperture and a macro close-focusing distance, while the Pentax is renown for its SMC coating, lustrous contrast, minimal distortion, and constant aperture. If you've got close to $400 US to spend on multi-purpose lens for your Pentax DSLR, these are the two main competitors for summer 2006.

The Sigma lens has more features, but if macro or zoom reach don't tickle your fancy that much, it has some minor detractions that let the Pentax keep it's good reputation intact. The Pentax lens is presently sold with a rebate (until July 6th, 2006), and will cost less than the Sigma if you act really soon. If you're thinking about making a jump onto the bandwagon for one of these lenses, here's a quick breakdown of the qualities of each.



Sigma 17-70mm DC Macro

Zoom Range Equivalent: It has a 35mm zoom range of 25.5mm to 105mm.

Size and Weight: 72mm filter ring, 82.5mm long, 455g (16oz)

Image Quality: The good news is that it isn't as soft as the 18-125mm, and that there are definite sweet spots (namely F5.6 and F/8, between 40 and 70mm). It exhibits some slight vignetting and barrel distortion at the wide end, but as Photozone says, "still not worse than the direct competition." It's particularly good at low-contrast detail. CA is average for a mid-range lens, mostly towards the wide angle end and usually not more than a pixel or two of color shadow in high-contrast backlighting situations. Good flare resistance, but a rather small lens hood.

Bokeh: 7 aperture blades, not exactly creamy, and harsh with bright contrasts, but good.

Manual Focus: There's no damping on the focus ring, so it's not easy to fall in love with in manual. But there is a focus lock at 17mm to avoid creep if you're at the wide end. IF (internal focusing), but reverse to the typical Pentax direction.

Auto Focus: Its focus ring will rotate in AF mode, but the filter ring stays put for circular polarizers. No Quick Shift for manual focusing while in AF mode. Also in AF, there's a mico-motor that's a little bit loud, but it speeds up the AF considerably, making it one of the fastest on a Pentax DSLR body. Good at fast low-light hunting.

Macro: You can get pretty close, under 8". 1:23 magnification is possible.



Pentax SMC-P DA J 16-45mm ED AL

Zoom Range Equivalent: It has a 35mm zoom range of 24mm to 67.5mm.

Size and Weight: 67mm filter ring, 92mm long, 350g (13.5oz).

Image Quality: SMC coating kills flares dead. This lens has some of the most distinctive contrast ever found in a Pentax lens, comparable to a Canon L glass twice as expensive. And it's fairly sharp (although don't expect prime or Limited results), capable of delivering crisp detail wide open and consistent contrast until stopped way down. The minor CA is limited mostly towards the wide angle end in high contrast areas, but it's usually less than a pixel of shadow. Like the Sigma, watch out for flash vignetting if your flash can't handle the 16mm end (I'm talking to you, AF-360 FGZ). Barrel and pincushion distortion are amazingly tame. A lot of Pentax users swear by this lens as their standard DSLR choice.

Bokeh: 8 aperture blades, silky smooth for a zoom lens, but a little jumbled in high contrast areas.

Manual Focus: There's nice damping and it's Quick Shift capable, meaning that you can keep it in AF and make manual adjustments. IF makes it fun. The petal shaped lens hood sports a panel for polarizer adjustments.

Auto Focus: Not the fastest, but it's quiet. Decent in low-light.

Macro: Not really meant to have any macro attributes.

Links: Sigma 17-70mm DC Macro, Sigma 17-70mm Review Links, Pentax SMC-P DA J 16-45mm ED AL, Pentax Summer 2006 Rebates, Sigma 17-55mm Announcement, Photozone review of Sigma 17-70mm DC Macro, Boris's Pentax DA 16-45mm Page

2 comments:

gestaltungswille said...

Thank you for your usefull information.
Just a little correction: The Pentax SMC DA 16-45 ist not a "J"-lens. Pentax states that "
The PENTAX FA-J series is a line of affordable autofocus lenses without an aperture ring"
The DA-lenses are designed only for digital cameras.

OK-1K said...

I don't think of it as a typical "J" lens either (the first ones weren't that remarkable), but that's what Pentax calls it:

"The smc P-DA J 16-45mm F4.0 ED/AL is well-suited for advanced amateurs and professionals." - Pentax's website here.

The J designation indicates that the lens is designed for both SLRs (with limitations) and DSLRs. You'll want to keep in mind that on regular SLRs as there's vignetting under 24mm.

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