5D2 + 135 f/2 questions

[cuthbert]

well i went out with my canon ef 135 f2 for the first time in a while and noticed that pretty much every one of my photographs was a bit soft. AI servo tracking was even poorer, just not good at all.

i have noticed it before, but put it down to bad technique/subject movement but when i look back i think that the lens has perhaps always had a tendency to front focus and closer examination of the shots i took at the weekend confirmed this.

for instance, on one shot where i the top focus point squarely on the eye/face, the face was a bit soft but the tips of the subjects shoes were perfectly in focus (i was far enough away to get an entire persons body in the frame at 135mm)

i'm going do to some more tests with camera/tripod etc just to confirm as these were handheld, but it is happening consistently and i get more keepers with my sigma 85 1.4 wide open, so i whilst i am prepared to put some missed focus shots down to either subject/camera movement/user error, in some of the shots the point of focus was so far away than there would be more than enough dof (10cm or more).


anyway, i gave the canon service centre a call on 0844 369 0100 who logged my call and then gave me the number to Colchester Camera Repair.

I then called them and they quoted me £95 + vat + shipping for a calibration which seems a bit excessive. sadly the lens is out of warranty by about 3 weeks (though will check)

is this normal? i thought canon had their own repair centre too ? why did they divert me to a 3rd party repair centre?

i am going to see if i can fix the problem myself with a micro focus adjustment, but ive heard of people on this board sending their kit straight to canon elstree. just a bit confused!

 

[arad85]

Yes - option 2 on the canon phoneline - not 1. At a guess, they suggested there as it will be more local to you.

Try microadjusting the lens. As it's a prime, it should microadjust well (zooms tend to be a bit of a compromise as you have multiple zoom lengths).

Canon Elstree quoted me £60 all in the other day for one of my lenses.

 

[cuthbert]

Thanks Andy, the telephone menu system is a bit misleading - it's worded as though it's for existing problems not reporting a new one.

I did go through option 2 and they quoted me the same price, so that's a bit easier to stomach.

I've done some tests this evening and my initial findings are that using the centre point, the lens is spot on. after 10 or so tripod mounted shots, the difference between quick focus af and live view af was either non-existent or minimal - certainly with tolerance.

but with the outer focus points, things are different. i'd say it consistently front focuses about 5-6 micro focus adjust increments maybe 50% of the time. the other times it's what i'd describe as being within tolerance. not quite as spot on as the centre point, but not far off.

so, i'm guessing that i'm probably just expecting too much of my 5D2's outer focus points?

Does anybody else have a 5D2 and 135 f2 and notice the same behaviour?

Any feedback greatly appreciated.

 

[cuthbert]

Shameless bump... anybody?

 

[grum]

I don't have this lens or 5D II but I have a 5D MK I (which I believe has pretty much the same AF system) and I don't find the outer points very reliable in terms of focus accuracy.

 

[seriousrikk]

I recommend you discuss it with the shop where you purchased the lens.

Just because it is three weeks out of warranty does not mean you have to foot the bill. Sale of goods act is you friend there.

 

[cuthbert]

Thanks all.

Reading this thread here: http://www.flickr.com/groups/canondslr/discuss/72157626102027496/

seems to suggest that this is perhaps to be expected, it's interesting that the poster "adr!@n" also mentioned that the outer focus points were out by +5 MFA increments with his 50L - just the same number as mine seem to be out by.

I guess fast primes with narrow DOF really does push the limits of the outer focus points and as i've been using my 2.8 zooms a lot recently i guess the sightly less accurate focussing of the outer focus points is cancelled out by the wider dof - as you note, it isn't out by much, but enough to be noticeable with a fast prime.

i always noticed that with the lower contrast subjects the outer focus points struggled more, but i hadn't really done that much testing to see how less precise they were.