canon 70-200 f4l focus problem!!

placeonthecorner · Sep 11, 2007

hello folks.
So i picked up a 70-200mm f4l off ebay and it came today.. i was super excited.. but as soon as i tried it out i noticed that the auto focus was terrible.. it doesent seem to focus on anything.. the only way it works is if you keep pressing and releasing the trigger halfway and eventually it finds the focus... am i doing summit wrong?... what factors would effect this lens auto focusing?-- manual focus works fine.

Frequent Traveler · Sep 11, 2007

Here is the problem - it's spelled C-A-N-O-N...

OK - just kidding there. I gotta make it real clear to all the Canonites i'm just kidding along or ELSE (i'll get spammed to vitual death!!!).

Maybe check the obvious things like fully charged battery, the lens has a good connection in the mount, clean contacts, etc.

From all reports, this lens, if i'm seeing it properly as the L model, has an outstanding reputation with some of my Canon shooting friends.

fm

Alex_B · Sep 11, 2007

with my Canon L lenses I made the experience that AF speed and behaviour depend on how well the lens is adjusted. the same lens would behave totally different.

Maybe your lens needs to see the Canon doctor ... just an idea.

placeonthecorner · Sep 11, 2007

well the guy now says he has never used it on auto focus (?!).. ive also read that these lenses have a rep for faulty autofocus.. im screwed i think...

Frequent Traveler · Sep 11, 2007

Maybe he/she will be honorable and offer full refund - it never hurts to ask. Did the auction mention the lens' functioning performance? If he/she said it worked, well maybe that will leverage his/her conscience.

That simply stinks...

Alex_B · Sep 11, 2007

placeonthecorner said:
well the guy now says he has never used it on auto focus (?!)

this sounds like the standard excuse for not telling about a faulty auto-focus he knew about.

placeonthecorner · Sep 11, 2007

yea it defo said it was only 10 months old and only used twice... it should be still under warranty, but i think he got it from the states because it has a U.S. warranty card, and it came with the hood which i dont think it did over here in the uk.. worse case scenario, how much will cost to fix?.. i feel weeks of hastle commencing right.....now.

Alex_B · Sep 11, 2007

placeonthecorner said:
worse case scenario, how much will cost to fix?..

if it just has to be adjusted, then I would guess well below 100 pounds.

if parts have to be replaced, not sure ...

placeonthecorner · Sep 11, 2007

jesus, it took me months to save for this... ive asked for a refund, but im not confident.. il let you know.. and thanx for the info & advice.

Big Mike · Sep 11, 2007

Does that lens have a focus limiter switch?

placeonthecorner · Sep 11, 2007

you can switch from 1.2- infinity and 3.? to infinity...

Alex_B · Sep 11, 2007

Big Mike said:
Does that lens have a focus limiter switch?

good point! I think it has.

if that would be set to short distance focusing, then any long distance focusing could be slow/quirky

placeonthecorner · Sep 11, 2007

yea ive adjusted that.. both settings are slow/quirky.. i just tried it again and it wouldnt focus still.. it just hunts constantly..

Big Mike · Sep 11, 2007

if that would be set to short distance focusing, then any long distance focusing could be slow/quirky

Isn't it the other way around? You can always focus on far away things...but if the switch is set to ignore the close range...then anything within 3.?m can not be focused on.

So make sure that you have it in the full range setting. Another stupid question...but are you focusing on something that is relatively close...maybe even closer than 1.2m? Because it will never focus that close.

Go outside and give it a try.