Pentax 50-200/4-5.6 Lens Review

by Josh Root; created July 2007

The Pentax SMC 50-200mm f/4-5.6 DA ED is a well-built midrange zoom lens with an attractive sticker price of $249 (August 2007).

In a typical two or three lens DSLR kit, the idea is to have a lens to cover the wide-to-mid zoom range, and a lens to cover the mid-to-telephoto zoom range. The Pentax SMC 50-200mm f/4-5.6 DA ED covers the mid-to-telephoto range very nicely. It is a lightweight, compact and user-friendly lens. The DA designation signifies that the lens is specifically designed for Pentax's digital SLR bodies. The size and weight of this lens makes it a natural choice for travel photography and it fits easily in the smallest of camera bags. The main limiting feature of this lens for an advanced photographer is the fact that it is not a 2.8 lens. Due to the 4-5.6 maximum aperture, a sunny or bright overcast day is needed to get the most out of the Pentax 50-200. Photographing indoors using available light is very difficult and photographing in a dimly lit location, such as a bar or club, is virtually impossible at any reasonable shutter speed. That said, there is no lens in the world that combines a large maximum aperture, high quality images, compact size, and reasonable price.

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Josh Root

Josh Root

Josh Root

The Pentax 50-200's image circle covers the 23.5mm x 15.7mm APS-C sized CCD in Pentax (and Samsung) DSLR bodies and will not work properly on Pentax 35mm film cameras. The lens has an angle of view from 31.5 degrees to 8.1 degrees which is equivalent in focal length from 76.5mm to 306mm in the 35mm format. 75mm is a nice group portrait length and 300mm will allow you to fill the frame when shooting a single person from a distance.

One of the features that helps keep this lens's size and weight down is the aforementioned 4-5.6 maximum aperture. As stated above, this limits its usefulness in low light situations and makes it harder to isolate the subject from the background using a shallow depth of field. The 75-300mm effective focal length makes it a good choice for photos of kids playing sports. However, due to the slow AF speed, capturing fast-moving action is somewhat challenging. Autofocus is driven by the old Nikon-style "screwdriver blade" body motor and is slow by the standards of any USM style lens (Canon's USM or Nikon's AF-S for example). If it isn't quick, it is at least accurate. The 4-5.6 maximum aperture does seem to sometimes cause problems acquiring focus in low light situations.

Optics

The Pentax 50-200 is a medium complex design, with 11 elements in 10 groups including ED elements (Extra-low Dispersion). There is a very small amount of pincussion distortion throughout the range, but it is not noticeable in everyday use. No evidence of barrel distortion was found, though we did not photograph a test chart series. Sharpness is quite good for a lens of this price and zoom range. Even more impressive is the consistency from center to edge and from wide to tele. This lens performs quite well in all regards.

Construction

Josh Root

While the compact size of the Pentax 50-200 encourages its use as a travel lens, it should be noted that it is not weather sealed. Care should be taken when using it in wet or dusty environments. If you need a weather and dust sealed lens in this focal length range, you should look at the Pentax DA* 50-135mm f/2.8 ED IF SDM, $719.

The included lens hood for the Pentax 50-200 bayonets onto the exterior of the lens, leaving the 52mm filter and lens cap threads free. The lens hood can also be reverse-mounted on the lens for storage. The drawback is that the hood will now be blocking access to the manual focus and zoom ring. Pentax has included a feature on this lens they call the Quick-Shift Focus System, which is something like the "full-time manual focus" on some Canon lenses. This is nice for making fine adjustments or manually focusing in difficult situations. Or at least it would be if the Pentax 50-200 had a useful manual focus ring. As it is, the ring is small, hard to find quickly without looking, and rotates during AF. Despite all of this, it has a high quality feel that is nicer to turn than the manual focus rings on many other AF lenses and it does have distance markings, which are both bonuses for MF users. In addition, it is nice to see that Pentax is staying dedicated to manual focus and continuing to include MF rings on their lenses. While the ring could have been designed better, it is nice that it is there at all.

Weight is 9.2oz (261 grams), which balances reasonably well with the Pentax K10D body. A smaller Pentax DSLR body like the older Pentax *istDL, 18-55mm kit, $580, or the Pentax K110D, $432, would also be a wonderful fit for this lens. The lens's dimensions are a compact 2.6in x 3.1in.

Alternatives

Here are some other lens options to consider:

• Pentax DA* 50-135mm f/2.8 ED IF SDM, $719, Pentax's soon-to-be-released constant 2.8 internal-motor lens; said to be very well built.
• Sigma 55-200mm f/4-5.6 for Pentax and Samsung, $146, cheap and light, but image quality can drop in this price range

Conclusion

Overall, this is a fine lens and would make a good addition to a Pentax DSLR user's camera bag. It has a large and useful focal length range, while not losing much in the way of image quality in exchange. In fact, when comparing its low $240 price to its high image quality, this lens can be considered one of the best bargains in photography today. If low light photography is more important than price or lens size, you might consider other lenses in this focal range. For the average photographer, pairing this lens with a few telephoto prime lenses, aperture of 2.8 or faster, should overcome any low-light limitations of the Pentax 50-200.

Where to Buy

You can get this lens overnight from amazon.com. Their prices are fair and you help to support photo.net.

Specifications

More

• Photo.net Pentax forum
• photo.net street photography tutorial
• Pentax web site

Examples

Josh Root

50mm, f/4.5, 1/180th, ISO 400. The 50-200 isn't weather sealed, but it held up just fine in this wedding rainstorm.

Josh Root

80mm, f/4.5, 1/125th, ISO 400. With the large telephoto zoom range of this lens, I was able to capture a number of different compositions of the subject without moving from one stationary location.

Josh Root

200mm, f10, 1/350, ISO 200. The 200mm (equivalent to a full frame 300mm perspective) long end allowed me to photograph these children watching a juggler without being noticed. Their expressions of confusion, neutrality, appreciation, and excitement remained natural.

Josh Root

50mm, f10, 1/250, ISO 200. While the AF is not blazingly fast, the lens did respond quickly enough to allow me to take some wedding images.

Josh Root

160mm, f/6.7, 1/350, ISO 400. I had plenty of zoom range to photograph through the chain-link safety fence surrounding this logging show.

Josh Root

50mm, f/4, 1/500, ISO 400. This guy is surprised at the 50-200's quality considering that it only costs $240. Or maybe he was making faces at Hannah who was photographing next to me.

Josh Root

88mm, f/4.5, 1/60, ISO 400. Here is a situation where a larger maximum aperture would have been preferable. It was a dim cloudy evening, and I would have like to have kept my shutter speed up slightly higher to eliminate motion blur from the child and her mother's hand tickling her.