DA* 50-135 loose focus ring

Hey folks, looks like my troubles with new gear continues...

I've just received brand new 50-135 and it has loose focus ring. This loosness feel is more noticable to the one end of infinity than another. When I rotate the focus ring and then rotate it to opposite direction, the inside ring in the focus window catches up in 0.25-0.30mm and in that zone when it's more noticable I can hear a clacking sound if I rotate it fast enough. Other than that, focusing works well both in MF and AF but it's somehow annoys me and forces me to think do I have to send it back?

Thanks

Send it back as you'll only regret it later if you don't.

If you can, compare it with another 50-135, although that might be difficult where you live?

What you describe sounds just like mine, and it works fine. I suspect what you're experiencing is the working and sound of Quick Shift mechanism.

Thanks guys for your attention.

John, unfortunately I can't compare it physically because no local shop here, but some people on other forums said exactly the same as you about quickshift mechanism. One of the most experienced user there told me that all of his star lenses behive that way. Only one user of DA* 300mm lens mentioned that his lens has no play in ring at all. I'm totally confused What I have discovered also is that other lenses from other manufacturers with some similarities in focus mechanism like quickshift also has this kind of behaviour.

John, did you get it new or user one?

Mine was new. I also have the 300, which I haven't checked. I actually checked my 50-135 before answering your post. As I said, no problems with it, other than the fact that it's slow to focus, which is a characteristic of this lens too!.

Personally, I'd just get on and enjoy making photos with it. It's a great lens!

I have at least one DC motor lens too. I'll check the 300 and the other lens and let you know what I find.

Thanks a lot John!

Now as you mentioned the DC motor, I've remembered that during testing I've immediately checked my 16-85 lens because it also has quickshift. It also has this thing but because its focus ring in tiny compared to 50-135 and located towards mounting, you barely notice it but it is there. Image quality out of the 50-135 is just unbeliavable...

John, here's video:

link

sorry for annoying background

That looks like backlash. link to Wikipedia link

bforbes, thanks, yes I know that this is backlash, I just wonder if it should exists in this lens

Morning Lev. Checked my 300. The backlash is not quite as pronounced as the 50-135, but then again it's a prime so doesn't have quite such a complex focussing mechanism as a zoom. There is also a discernible 'knock' if I use the Quick Shift past infinity.

I guess it's one of those things. If you think that there's a problem with the 50-135, and it's easy to do, then swap it for another. Don't be surprised, though, if the replacement exhibits exactly the same "issue".

As to whether backlash should exist in the lens, it is unavoidable for nearly all reversing mechanical couplings, although its effects can be negated or compensated for. In many applications, the theoretical ideal would be zero backlash, but in actual practice some backlash must be allowed to prevent jamming. Reasons for the presence of backlash include allowing for lubrication, manufacturing errors, deflection under load, and thermal expansion.

hi!!

Don't be surprised, though, if the replacement exhibits exactly the same "issue"

Well, that's what I'm afraid of!

Did you see my video? I wonder if that is look like yours? exactly like that or close to that.

thanks for your help I really appreciate!

I have the DA* 60-250 lens which is of the same era. It also has the "backlash" sound but you have to be listening out for it. It is also normal for the click you hear when you reach the extremes of focus. As long as the focus ring turns smoothly I would not worry.

On your video from 30 seconds onwards as you turn the ring towards infinity, it appears to become a bit stiff and doesn't turn smoothly ? Is this correct ?

pschlute, absolutely right!! It becomes stiff in either way and I think it's normal, I'm more worried about backlash, as long as I'm guessing, more free play you have, more loudly you'll hear the clacking sound. My main concern is how much this gap or dead zone should exist in good copy? in my case, it's about 0.30mm. I can operate it fully silent if I'll rotate the ring smoothly but if I'll do it fast enough (and in some conditions you'll have to do that way) then I can hear this clacking sound, probably gears engaging.

I would be more concerned with the fact that the focus ring is not smooth throughout it's travel. Your video appears to show it quite "notchy" turning towards infinity, and if that is indeed the case I would return the lens for a replacement.

no no, the focusing ring movement itself is very smooth (well it's bit loose until gears engage each other), not as stiff as zoom ring though but it's smooth.