A7C not playing nice with 90mm f2.8 Macro?

[DustyBin]

I recently bought a secondhand 90mm f2.8 Macro that seems to 'rattle' a little bit when I put it into manual focus. More of a 'clunk' really as something inside shifts. More noticeable when at the short end of the focus ring. There might be some movement when in AF (it's not not the AF motor whine before you ask), but its more noticeable in MF. When I switch off OIS on the side of the lens, the clunk disappears (whether AF or MF).

Now... I was trying this out on my A7C. Here's a short video...

https://youtu.be/WWiZ9BX1DWI

Today, I mounted it on my A9 and there is no 'clunk'. Got me wondering... has anyone else experienced a bit more noise when pairing an A7C with an OIS lens, particularly one, such as the 90mm, with floating elements.  Perhaps the smaller IBIS isn't co-ordinating quite as well with OIS in such a lens.

A7C works fine with every lens I have (and I have a few!). IBIS works fine. Sensor does 'clunk' a bit when switched off (as does my A9), as would be expected . This combination of body and lens is the only one with the clunk.

[HannahEd01]

Hey DustyBin, does the camera do the same thing with other lenses?

[DustyBin]

It doesn’t… all the others act ‘normally’.

I tried the lens on my A9 and that doesn’t make a noise.  So, I don’t think it’s the lens or the A7C that’s causing the noise, but the combination.  I wonder if the 90mm is made somewhat differently to everything else I own due to it being a macro and that difference is causing this quirk.  Perhaps A7C and 90 macro is a fairly rare combination?  And, the smaller IBIS unit on the A7C just reacts a little differently.

Given the lens plays nicely on my A9, I’m not too bothered now, but it would be interesting if there were any potential insights.

[HannahEd01]

Hey DustyBin, could you upload a video where we can hear the noise?