Wednesday, November 13, 2013

In praise of Pentax’s shake reduction system

Pentax recently released its high-end K-3 DSLR. I’m not immediately in the market for it, having recently purchased the K-5 II, but I want to take this opportunity to praise Pentax for the sensor-shift shake reduction system in their camera bodies.

The obvious benefit is reduced blur in handheld exposures, even with old lenses, but I’m instead focusing on the other benefits of the system. You see, once Pentax decided to implement shake reduction through sensor-shift technology, they made the extra effort to think about the other capabilities that such a system could bring to the camera. These include:

  • Dust removal. In the K10D and some other bodies, the sensor shift mechanism was used to reduce dust build-up on the sensors. (This has been superseded in more recent high-end bodies by an ultrasonic vibration of the antialiasing filter.)
  • Composition adjustment. When working on a tripod, the sensor can be moved manually within the range provided by the SR system, to tweak the composition. This is useful for macro work, and it also allows expanding the field of view slightly through panorama stitching, without parallax.
  • Automatic horizon leveling. On bodies with a rotational axis for SR, the camera can automatically level the horizon.
  • Astrotracer. With the O-GPS1 accessory, the camera can use the SR system to follow the motion of stars on the sky, allowing significantly longer exposures without star trailing.
  • User-selectable antialiasing. A marquee feature of the K-3, the camera can use the SR system to prevent aliasing artifacts without the use of a permanent optical low-pass filter. No more having to choose between a K-5 II and IIs, or Nikon D800 and D800E!

Kudos to the Pentax engineers for continually thinking about new applications of their SR system.

This post is dedicated to Bill Robb.

Monday, November 11, 2013

Pentax K-5 II and strong filters

I recently picked up a Sigma 10-20mm f/4-5.6 ultra-wide-angle lens for my Pentax K-5 II DSLR. On the first day that I took it out, I tried using a 1000x neutral density filter to blur water in a stream. The results were disappointing:


Even though the light was pretty dull, I attributed the bright horizontal streaks to lens flare from the cheap, uncoated filter, and I didn’t think much more about it.