I just received a refurbished EM1 and will be using it for the first time tomorrow at an indoor track meet. I'm planning to use a P42.5/1.7 and an O25/1.8. Using the non OIS Oly lens on the Oly body is a no-brainer. But the Panny has OIS, and, unlike some Panny lenses, it has no switch to turn it off. The cameralabs.com review states some uncertainty about the effects of OIS active concurrently with the IBIS on the EM1, but, as one would expect, the conclusions about IS in the review concentrate on slow shutter speeds. For the meet, I intend to shoot at faster speeds to avoid motion blur, and was wondering if there are any adverse effects with having the EM1 IBIS on while the OIS (which is presumably always on in the P42.5/1.7) is "competing" with the body. Does anyone who has used this combo at faster shutter speeds have any thoughts on the matter?