Pentax smc DA 200mm f/2.8 ED (IF) SDM Lens

In order to augment my Pentax DA*50-135 f2.8 with more reach, I had been interested in the Tamron 70-200 f2.8 but decided to go with the Pentax DA*200 f2.8 - I really wanted the SDM focus motor of the Pentax lens. Online professional lab tests indicated typical prime lens performance in near zero distortion and across-the-frame level sharpness over a wide range of apertures. But the caution here is the surprisingly high level of purple fringing they experienced at open apertures.

The construction, feel and appearance of this lens is nothing short of the best offered by Canon and Nikkor. Unless I'm mistaken, the DA* 200 has a metal body and the only detectible plastic is the huge impressive lens hood edged in rubber. In comparison, the DA*50-135 is quality plastic with focus ring action that isn't quite as butter-smooth as the DA*200 and has internal rattles that the 200 doesn't (zoom mechanism?). The pictures taken with the DA* 200 I found to be outstanding. While the lab numbers for sharpness are a tad lower than the DA* 50-135, the resultant images are every bit as good and actually better in across-the-frame sharpness and contrast. I've been very impressed with the several hundred pictures I've taken so far with this lens. However, there is a down side to consider.

When I first mounted this lens on my K10D, the AF system would jam near infinity. I had to switch to manual mode to free it. This happened a few times and then never happened again. The next thing I noticed was that the lens had a significant back-focus problem. On my K20D, however, it was fine and only needed a small amount of AF adjustment provided only by the K20D. But I soon learned that the problem was the K10 camera and not the lens; some K10Ds apparently have been experiencing a back focus problem, but one that is now correctable via a software program from Russia that let's one hack into the K10D's firmware (v1.3) and bring up the Debug Mode menu. This allows for focus adjustment much like the K20D but not for individual lenses. Problem fixed. The DA*200 and my DA*50-135 now focus perfectly on my K10. So the only remaining issue here is the harsh purple fringing on edges of medium to high contrast objects and features shot at anything under f4.0. The fringing can be quite pronounced and annoying. It also appeared that the lens was noticeably less sharp at f2.8, but I found that softness to be more a product of the fringing. However, purple fringing can be greatly reduced, if not eliminated, with various software photo editing tools available.

I had hoped that the DA*200 f2.8 would be a perfect lens given the price and the fact that it is a prime and not a zoom. But few lenses are perfect, so it becomes a matter of the buyer deciding whether the overall performance relative to the price meets your expectations. For me the fringing issue gave serious pause, but the exceptional look and feel of this lens in combination with the overall quality of the shots I've taken have convinced me to keep and treasure it. Next consideration: how much would the image be degraded and fringing increased with a 1.4x teleconverter to produce a 280mm f4.0?

Update (11/11/08): I discovered that it is important to ensure that the auto focus adjustment in the camera (K10 or K20) is properly set for this lens and balanced across all apertures. It appears that apertures of f2.8 through f3.5 tend to shift toward back-focus - at least on my copy. This means that if you are boarderline back-focusing at f4 and higher, but still sharp, you may slide into a back-focus situation under f4 without knowing it, as I was, and images will be slightly fuzzy. This in combination with purple fringing, when it occurs, could result in a foggy-halo effect that I had been seeing in many of my pictures taken in brighter light. Once I curred my slight back-focus, images shot at or near f2.8 are now just about as sharp as those taken at f4 and higher. In resolving the AF adjustment issue with this lens and comparing results between the K10 and K20, I was reminded of what a nice improvement in resolution and noise reduction the K20 is over the K10. But regardless of what Pentax D-SLR you use, this lens will get you truly impressive results.

Update (11/22/08): I tried the Tamron AF 1.4x tele-converter on this lens and was surprised by the quality of the images - no noticeable reduction in sharpness, contrast or color. Purple fringing, when it occurs, is no worse with this TC. I was also pleasantly surprised when I found that the SDM focus system still works, although it tends to hunt for focus just a bit more under lower light conditions. The Tamron AF 1.4x essentially turns this lens into an impressive 280mm f4. So good are the images with the Tamron TC on the DA* 200mm that I no longer have an interest in either the Pentax DA* 300mm f4 or the Sigma 100-300mm f4. While this TC looks to be a perfect match with the DA* 200, interestingly, quick tests with the DA* 50-135 did reveal some degradation in sharpness, contrast and increase in aberrations.

The Pentax DA* 200MM f/2.8 ED IF SDM Lens was quite an upgrade to my relatively small stock of lens. I shoot different photographic seens most of which are sport events in low light conditions. This fast lens excells in those environments in combination with my K20D DSLR. AF speed is remarkable. Clarity is brilliant. I have mostly "keepers" in fast action such as high school football games. The value for dollar makes the Pentax DA* f/2.8 200MM ED IF SDM Lens an outstanding investment in your photography. This lens has taken my game to a new level. The first sport event photo competition I entered I won 1st place with this incredible lens. I currently use this lens for approximately 70% of my shots. If you have the photo bug this lens is a must for you.

I've gone sort of nuts buying Pentax lenses for my k5 and kx. I have the 10-17 Fisheye, 15mm Limited, 21mm Limited, 35 mm Macro Limited, 40 mm Limited, 70 mm Limited, 200mm DA*, 50mm Takumar m42 and just bought the 50mm f1.2 SMCA. I take a lot of events/street, flowers and nature shots. I don't use this lens a lot partly because I don't need a long lens often. This is a big lens with a lot of glass. It's an amazing work of art to hold. When taking pictures, what I like most about this lens is the ability to create a nice bokeh and compress the depth of field. Compared to the shorter length lenses I find this one to have a lot less contrast and somewhat less sharpness. Maybe that is to be expected with a longer lens. On the positive side, I don't find that the sharpness and contrast vary as much with different apertures compared to shorter focal length Limiteds. It's quite usable wide open.