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Pentax DA* 200mm f/2.8 Lens Review
by JerryJ -  3/21/2008

When Pentax recently released their updated flagship K20D and mid-range K200D, they also offered a series of new "DA" lenses designed specifically for Pentax DSLRs. One of the most impressive lenses from this latest release is the Pentax DA* 200mm ED (IF) SDM f/2.8 prime.

Pentax 200mm
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After a few years of criticism over the lack of modern telephoto primes and long zooms, Pentax has stepped up to the plate in 2008 with some excellent new high-quality lenses for DSLR users. Can Pentax re-establish its former popularity with its latest line of cameras and lenses? If this lens is any indicator, they may be on the right track.


ERGONOMICS

Lens Mount

The Pentax DA* 200mm ED (IF) SDM f/2.8 prime is offered only in the Pentax KAF2 lens mount, a modernization of the long-lasting Pentax K mount. With a crop factor of 1.5x on DSLR cameras, the lens has a 35mm equivalent range of 300mm.

What separates the KAF2 mount from earlier versions is the addition of a contact for new lenses with a built-in Supersonic Motor (SDM), which the DA* 200mm employs.

Design and Build Quality

The Pentax 200mm is a fast aperture, internal focus (IF) prime, designed to cover the moderate telephoto focal length range and deliver sharp, professional-level image quality in any type of lighting environment.

This isn't a $200 telephoto lens we're talking about. The DA* 200mm is a massive, heavy lens with rugged build quality that is second to none in its price range ($1,100). Fit and finish are first rate with a mix of metal alloy and polycarbonate. The broad ridged-surface rubber focus ring is perfectly placed with the perfect amount of dampening and no focus creep. The DA* 200mm also features a weather resistant and dust resistant body which makes it perfect for use and abuse in any environment. Markings (distance scale in both feet and meters) are clear and easy to read and include a basic depth of field scale.

One feature that's worth mentioning is that the DA* 200mm lens uses fully automatic diaphragm control: you can't manually select the aperture by turning the diaphragm collar on the lens because there is no diaphragm collar.

Optical construction is all-glass with 9 elements in 8 groups, with ED elements and Pentax's new Super Protect (SP) lens coating which protects the exposed lens elements. The filter diameter for this lens is 77mm.

Handling

As noted, APS-C style sensors in Pentax cameras have a 1.5x crop factor, so this 200mm lens performs like a 300mm lens. The telephoto focal length range makes this prime absolutely perfect for sports and wildlife photography. The 200mm focal length and f/2.8 aperture has also become quite popular for wedding photographers shooting indoor ceremonies with available light.


PERFORMANCE

Auto Focus

The Pentax 200mm lens is driven by Pentax's new Supersonic Motor (SDM) system which provides quieter auto focus and smoother focusing. Indeed, our tests showed that auto focus is impressively quick, quiet, and smooth - the lens finds the subject and locks focus in what is essentially real time, even in low light.

Pentax 200mm
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When the lens does have trouble locking focus on a low-contrast subject the lens travels from the minimum focusing distance of 3.9 feet to infinity and back. It would have been nice if Pentax engineers had included a focus limiter on the lens so that it doesn't have to travel the entire focus range, thus making autofocus faster.

Manual Focus

Focusing manually with the Pentax DA* 200mm ED (IF) SDM f/2.8 lens is much easier than with older Pentax lenses. As with all lenses in the DA family, there is no need to flip the MF/AF switch on the lens barrel or camera body because this lens features "quick-shift focus" (full-time autofocus override).

All you have to is point the camera at your subject and turn the MF ring until the subject snaps into focus. You never have to turn off autofocus again in order to adjust manual focus. The manual focusing provides just the right amount of resistance when turning. Unfortunately, to turn the focus ring from its closest focusing distance to infinity is roughly a 300-degree turn around the barrel. This makes manual focusing with the 200mm more than a little time consuming if you aren't already close to the correct focus distance.

Image Quality

The default "bright" color tone setting on the latest generation of Pentax DSLRs produces quite a bit of image contrast, but the DA* 200mm ED (IF) SDM f/2.8 takes contrast and sharpness to a whole new level. Knowledgeable photographers using SLR bodies realize that good lenses need to produce sharp images with good edge definition, smooth "bokeh" (out of focus areas), and accurate color.

Pentax 200mm
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At the widest aperture of f/2.8, the DA* 200mm is reasonably sharp from one edge of the frame to the other with just a little corner softness. When stopped down to f/4 or more, the corners are virtually as tack sharp as the center. The Pentax DA* 200mm renders colors that are hue accurate, bright, and nicely saturated. This glass should be more than capable of resolving any detail needed for high resolution digital image sensors such as the new CMOS image sensor in the Pentax K20D.

Pentax 200mm
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As expected, the Pentax DA* 200mm ED (IF) SDM f/2.8 shows no noticeable barrel or pincushion distortion. Flare and internal reflections are very well controlled, but the large front element is a little prone to flare in strong sunlight if you aren't using the included lens hood when shooting. Chromatic aberration (color fringe around high contrast lines) is also well controlled; we only found minor color fringing on high contrast edge demarcation areas when test images were viewed at 200 percent or greater magnification.

Pentax 200mm
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Vignetting (dark corners) was negligible to non-existent at all apertures with and without the hood. The nine-bladed diaphragm renders exceptional bokeh, and the f/2.8 aperture gives you genuine out-of-focus backgrounds worthy of a full-page spread in a fashion magazine.


CONCLUSIONS

Like many photographers who first started using cameras in the last century, I have a special place in my heart for prime lenses, and for Pentax. It's true that modern zoom lenses give casual shutterbugs the most flexibility when composing and shooting their images. But a high-quality prime lens, such as the Pentax DA* 200mm ED (IF) SDM f/2.8, is an experienced photographer's best friend in that primes "suggest" a composition or frame for a particular shot, making it easier for the photographer to see lines and options for framing the image.

In the hands of a good photographer, the new Pentax's focusing speed, quiet focus, edge-to-edge sharpness, smooth bokeh, and rugged durability are the perfect ingredients needed to craft stunning images that rival those from other manufacturers' pro-series lenses.

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