I’m currently without any second digital camera, so I borrowed one to get these shots. If a new Olympus Pen with built-in viewfinder should ever appear, it could be a nice second body for me ;)
Anyway, you can see how much bigger the OM Zuiko 200/4 is over its smaller brother, the 135/2.8 – well, none of them are really huge, anyway. And don’t forget the reach that the 200 gives on the E-M5 – on a 24x36mm camera, you’d need a 400mm lens to match it.
Note that most OM Zuikos have their aperture ring placed up front on the barrel, in contrast to almost any other legacy SLR glass. It’s actually very ergonomic this way, especially on a mirrorless body: You hold the camera with your right hand and balance the lens with the left. Now, the aperture ring up front is much more convenient when you focus with the lens fully open and then quickly grab the aperture ring to close it down one or two clicks. With a conventional rear-mounted aperture ring, you’d loose balance when you grab it between focusing and taking the shot.
On conventional SLR cameras, this is not a big deal, as the lenses then would work with automatic stop-down aperture.