I first noticed this with my Olympus M.Zuiko 12-40mm f/2.8 Pro. I’d knocked it off a table and, although it didn’t fall very far, I gave it a little shake to check nothing had come loose and there was a noticeable ‘clonk’ from inside. Not good!
I didn’t have another lens with me so I had to put it back on the camera to check it out and hope for the best. The shots were fine, which seemed weird, but then I noticed that with the lens on the camera and the camera powered up, the clonk was gone.
Its turns out this wasn’t a one-off. I now have a sample of the new version of this lens, the OM System M.Zuiko 12-40mm f/2.8 Pro II, and it’s exactly the same. This makes me think that there’s something else going on, and that there’s nothing broken at all. And the only explanation I can think of is that the lens doesn’t ‘park’ its focus group when it’s switched off, and that this focus group is left to ‘float’ until the lens is hooked up again.
I’m sure it’s perfectly harmless, but I don’t like it. Especially in a pro optic that’s one of the best MFT lenses on the market.
It’s not just this lens, either, as I found out when I reviewed the Fujinon XF23mmF1.4 R LM WR. This is a fabulous lens optically and handles really nicely too. Except that when it’s off the camera, this lens also makes a noticeable ‘clonking’ noise. There’s no optical stabilization in this lens so, again – so I can blame that.
I’m guessing it’s the focus group ‘floating’ while there’s no power going to the lens. The XF23mm is one of the best Fujifilm lenses. It’s a professional lens, so this is not a bit of cheap corner-cutting.
I’m sure Fujifilm’s engineers have thought of all this and there’s absolutely no harm being caused to the internal elements. There are probably very good engineering reasons why it’s not practical to lock down internal elements when the lens isn’t being used.
Not every lens does this. My Canon RF 24-105mm f/4-7.1 IS STM is probably not one of the best Canon RF lenses, but it is rattle-free, whether it’s on or off the camera, and this lens has an optical stabilization unit as well as a focus group. But then my Canon RF 85mm f/2 Macro IS STM DOES rattle when it’s powered off, so there doesn’t seem to be any real consistency about this.
This might seem like a terribly minor thing to complain about, but once you realize you’ve got a ‘clonking’ lens it’s quite difficult to get it out of your head. Nobody likes it when mechanical things rattle…
