At just 382g, the OM System M.Zuiko Digital ED 40-150mm F4.0 Pro is almost half the weight of the Olympus M.Zuiko Digital ED 40-150mm F2.8 Pro without its tripod foot. And even when extended to its maximum length of around 124mm from the camera, it’s over 35mm shorter. Naturally, its smaller maximum aperture means it’s narrower as well, in fact it has a maximum diameter of 68.9mm rather than 79.4mm (or around 94mm if you take the f/2.8 lens’s hood into account).
OM System has also given the M.Zuiko Digital ED 40-150mm F4.0 Pro a collapsible design which means it can be shrunk down to around just 115mm for transport. The lens is collapsed by turning the zoom ring beyond the 40mm widest point and you just rotate it back towards the 40-150mm zoom range to extend it again. There’s a click stop at the 40mm point to let you know when you’ve reached the right point.
Once the lens has extended for use, its length doesn’t change as you zoom from one focal length to another.
Consequently, the M.Zuiko Digital ED 40-150mm F4.0 Pro is more portable than the more expensive M.Zuiko Digital ED 40-150mm F2.8 Pro. In fact, when I was testing the OM System OM-1 I was able to slip it plus the OM System 8-25mm f/4 Pro, Olympus 12-45mm f/4 Pro and the 40-150mm F4.0 Pro in my carry-on bag for a skiing trip along with all the usual travel essentials. I was even able to take the whole kit out with me on the pistes in just a small backpack.
While the collapsible design is great for portability, on at least 50% of occasions that I powered up the OM System OM-1 withe the 40-150mm f/4 mounted, the camera had to remind me to extend the lens. It gets a little irritating, but I like to collapse the lens between shots because it makes a smaller target for knocks.
Overall, the 40-150mm F4.0 Pro feels well made but it lacks frills like a customisable lens function (L.Fn) button and a manual focus clutch. There’s also a little ‘chatter’ in the broad zoom ring if you rotate it quickly backwards and forwards, but to be fair, it works perfectly well.
The manual focus ring, which sits further towards the front element than the zoom ring, has a smoother, quieter movement that more befits a Pro lens.
Like the OM-1, the OM System M.Zuiko Digital ED 40-150mm F4.0 Pro has a weatherproof rating on IP53, which means it can withstand water spray. There’s also a thin rubber gasket around the metal lens mount to help prevent water getting inside the camera.