Lenses tested

There were well documented problems of lens blurring at certain shutter speeds with the lens set at 42mm with early models of the lens that have been well documented on forums (e.g., dpreview). Panasonic was reported to acknowledge the problem and to indicate that the problem was fixed through hardware and firmware improvements.
The first lens I tested was purchased new in June, 2012 (serial number HN2AN030956) and was used for the main MTF50, light drop off, and parking garage test target. I did not detect shutter speed related problems in my intial tests with the lens, although few exposures were taken in the range from 1/100th to 1/200th second where shutter speed associated lens blurring had been reported.
I ran additional tests on a second new lens ( serial number HN2BE001844) received in July, 2012. I ran tests at 42mm using USAF1951 resolution targets while hand holding the camera and on a tripod at varying shutter speeds from 1/20th to 1/320 with image stabilization turned on or off. I repeated the tests on a tripod with a GX1 (starting serial number FT2BA702xxx) at 1/5, 1/10, 1/20, 1/60, 1/100, 1/160, 1/200, 1/400 and 1/640 with image stabilization on and off using a SFRplus chart and Imatest Master to calculate differences in MTF50. I found a shutter related effect. However, this initial test (below) had aperture and ISO variation that might be influencing the results in an uncontrolled manner.

I obtained a third new lens (serial number HN2BE001831) and reran the MTF50 and shutter speed tests at 42mm and 20mm on July 30, 2012. The tests were all run at f/5.6 and ISO 1600 and illumination of the SFRplus chart was varied with modeling lamps. Two exceptions were at shutter speeds of 1/10 and 1/5 where ISO was set at 800 and 400, respectively. Other methods used are HERE. Three cameras were tested with the third lens at 42mm: Panasonic GX1, Olympus OM-D EM-5 and Olympus E-P3.