Focusing ring issue with Cfi lens...

[Thomas73]

Hi all,

I recently checked a nice used Cfi 250mm lens. But, an issue with the focusing ring stroke me : it is like there are some grains of sand within the focusing mechanism. Unlike my other Cfi/Cfe lenses, it is not smooth...

So, I left it...

According to you, what is wrong : are there really grains of dust or a lack of lubricant?

Thanks for your feedback.

 

[polypal]

With used equipment you never know what this gear has been through.
There are many possible reasons for the problem you described.

Could be sand or other foreign matter found its way to the helicoid.
If this is the only problem and the lens does suit you maybe suggest to the owner
to have the lens serviced and buy it if it turns out ok.

Uneven movement or heavy points with a helicoid are more serious.
Those indicate damage from dropping the lens.
To correct that kind of damage is expensive.