Canon 100-400mm MkII Manual Focus

[GeeJay57]

Hi, I've had an EF 100-400mm Mk II since March 2015 and so far it has performed flawlessly and still does in AF mode. However, yesterday I noticed that the manual focus adjustment seems to have excessive slip.

I was trying to get a rough focus on a light aircraft at high altitude and with a recently acquired 1.4x Mkiii attached, was restricted to the central focus point only. The target was too blurred for me to put the central focus point on it with confidence, so I tried to use manual focus to help things along. The ring itself moves freely but the focusing is very vague and looking the distance scale movement, it seems reluctant to move reliably when the ring is turned. I don't use manual focus often, so I've not been aware of this fault/feature before.

Has anyone else had this problem?

 

[Gaz J]

Don't know if it helps you in a comparison but the focus ring on mine moves from 12 o'clock to 7 o'clock when going from closest focus to infinity.

 

[GeeJay57]

Don't know if it helps you in a comparison but the focus ring on mine moves from 12 o'clock to 7 o'clock when going from closest focus to infinity.

Thanks for the input.

Mine can take several revolutions to 'drag' the focus from one end to the other, it doesn't feel connected to anything. Seems to be a problem. Planning to go to the store I got it from and see if they can get it serviced. Alternatively, I will probably call the Canon service centre in Stoke tomorrow morning and see what they have to say.

 

[GeeJay57]

Update - have taken it across to Lehman's in Stoke for a service/repair. Hopefully nothing major and with luck will have it back soon.

 

[GeeJay57]

Update - Manual focus mechanism needs replacing. Estimated cost of repair including parts, servicing and recalibration an eye watering £330. So much for the durability of an expensive professional lens! I've rarely used manual focus in the time I've had the lens (just over two years) and am not impressed that the mechanism has failed. The repairer says it's an unusual failure... Terrific!

 

[GeeJay57]

Update - got it back this morning. All seems well, wallet is a bit lighter but that's the way it goes I guess.