Well, I can guess that the 25/0.95 is easier to focus on the EP2 than is my Canon 50/0.95 on the EP2. And the Canon is much bigger, uses 72mm filters. I usually keep the LTM Nikkor 5cm F1.4 on the EP2, and it is not a problem for focus. I like using the Nikkor as it will get to 18" and it is small enough for the fitted leather case made for the 14~42 kit lens.