When I first received my 85mmL MkII, it was backfocusing on my then 1Ds MarkII and it was adjusted by Canon. After I sold the camera the buyer told me that the camera frontfocused. Not sure what happened back then. And it doesn't need any microfocus adjustment on both 1D MkIII and 1Ds MkIII now.
35L front focused to a greater or lesser degree with 300D, 400D and 5D
85L front focused with 5D
80-200 spot on with 300D, 400D and 5D
several 17-40's spot on
I think with the fast primes having such a thin dof wide open its more obvious when there are focus issues.
17-40/4L - very slight forward focus
70-200/2.8L IS - slight back focus
300/2.8L - moderate forward focus
All corrected with little difficulty. I should add that IMHO, it depends of the body you are using. ON my 10D the 300/2.8 exhibited moderate forward focus yet on my mate's 1D it did not. This is not due to the 1D body being out of calibration either. I reckon the pro bodies are more accommodating of lens errors.
gdsf2 wrote:
Interesting finding so far: The "no problems" outweigh the "problems" by a bunch but more folks with "problems" replied in writing.
Jerry
That's the whole issue with reading these kinds of posts where people supposedly have such a terrible time with L glass.
It might seem as thought "many" L lenses have problems, but you're only reading about those who have problems (or think they do). You're not reading threads from the guys like me who've never once had an issue.
I have had focus issues with all three of my L lenses. Do I give a toss? Not really. I regard it in the same way as a regular service issue and a somewhat minor inconvenience.
That is my point. I especialy love the posts "I just ordered a new lens - how do I tell if it is sharp?" I don't know - how about taking some pictures! I think folks buying their first high-end lenses are being scared to death by the tone of some of these posts.
Problems do happen - but don't go looking for them. Use and enjoy your new lens. If the results look bad (under normal situations) then test the lens out.
Probably over thirty L lenses I have bought new and 4-5 pre-owned, all for my own use and not for speculation.
Out of those, if I remember correctly, the following ones have had a focus calibration error: 35L, 28-80L, 200 f/1.8, 50 f/1.2.....four lenses in total, which is not bad as a percentage of the total.
In about twenty lenses I've yet to have any problems (real world, or brick wall). And I am (part-time) professional, so it's not like the results aren't hugely significant.
Most of my lenses are bought used - so I'd expect more issues, but not so far at least....
Oh no - let's not turn this into a "how do I test thread." Anything but that. There are a gazillion such threads already. Do a search and see what I mean.
DavidP wrote:
If you haven't had any with problems, you're either blind, don't know how to test, or just haven't tried enough of them yet.
I'm not blind and I know how to test. I guess I just haven't tried enough of them yet. For what it's worth, here are those I own now, owned in the past, or have tried in the past:
I have tried a few other L models, such as the 70-200/4L IS and the 300/4L IS, but not for a long enough time to determine conclusively whether they were front- or back-focusing. I will say that the images I made with them all looked in focus.
I'm a bit confused as to why the OP would only want to know about L lenses, though. Because I've had a boatload of non-L lenses, and only one of them suffered from focus issues. I won't bother listing them here, as there are lots of them and I'm likely to forget one or more.
I don't doubt there are particular lenses, bodies, or combos in the world that have front- and back-focusing issues. The reports here from photographers I trust to know how to conduct such tests are evidence enough. But the internet amplification effect is definitely to blame for the general 'feeling' one gets that the problem is rampant and widespread. If it were as prevalent as one is led to believe by the reports here, neither my experience nor the results of this poll would be what they are.
I thought I was having back focus issues with my lens, enough that I them in for calibration. Each time upon return, it was the same as before. I figured that maybe my 5D body was the problem. Lucky for me, I read somewhere that custom function 17 (expanded AF points) can sometimes cause misfocus for non-moving subjects. I checked and sure enough, when I bought the camera I set that function thinking the expanded AF points would improve things. Maybe its just me, maybe my 5D really has issues, but after changing back to the default setting... I am in focus heaven.
