IBIS E-PM2, E-M5 vs Pentax K-30

tjdean01 wrote:

I have troubles with my pm2 and often keep ibis off. I have the 1/8 delay activated. Is 0s delay different than delay off?

Yes, 0-second AS is different from AS off as well as regular AS (1/8 s or longer). A shutter on a mirrorless camera normally goes through four phases when it operates: 1) first curtain closes (to prepare the sensor for exposure), 2) first curtain opens (to start exposure), 3) second curtain closes (to end exposure and read the sensor), and 4) second curtain opens (to resume live view). Regular AS introduces a pause between phase 1 and 2. 0-second AS instead introduces a short pause (about 1/40 s) after phase 2 and then resets the sensor and starts exposure electronically. This is known as an electronic first curtain shutter (EFCS). The important difference compared to regular antishock is that it not only eliminates the blur to phase 1 but also that due to phase 2 (which as a rule is the more serious problem).

On the E-M5 II (and in all likelihood all forthcoming Oly bodies), the first curtain does not move at all when the EFCS is used (0-second AS on). Consequently, no delay is required.

Also, based on your tests, electronic shutter is much better than mechanical. Is this only at slower shutter speeds?

The electronic shutter will be better with regard to shutter shock whenever there is blur due to the latter. The peak of the shutter-shock problem usually occurs at about 1/125 s (give or take 1/3 EV). It gradually disappears as you switch to faster as well as slower shutter speeds.

Finally, based on what you know, would a GM1 or a PL7 be a better performer than a PM2?

With regard to shutter shock: Yes certainly. The GM1 always uses EFCS with its mechanical shutter (it has no mechanical first curtain) and has a fully electronic shutter as well. The E-PL7 has the 0-second AS feature.

Thanks!