Sierra Trekker wrote:
OK, so I got my copy today and quickly tried it out tonight on my desk at home focusing on a number of highly definable items at 1.2, 1.8 and 3.2 and it was dead on. Used the center focus point on a 1DsII at roughly 2 feet from the subject............
Glad to hear it. Mind sharing your date code/serial prefix?
Sam Bennett wrote:
I'm not really sure what it would show you. I've tried it with the center point and off-center points on the 1D MKII, the center point of the XT I recently sold, and at the camera store this afternoon with an XTi they had sitting in a case. The result is the same every time. And shooting with the 50/1.4 is identical settings yields "perfect" focusing. Every time I do this test I shoot multiple shots -- between 3 and 5. Focus, take the photo, de-focus and re-focus, take another, etc. With this problem, the lens will literally never focus accurately. It's not like, one photo is in focus, the next is not... they're all out of focus.
I'm no stranger to fast glass. I shoot primarily with primes, usually wide open. This is both with static subjects and fast moving sports subjects. I know how to pick good focus points and what will give AF systems the heebie jeebies. My lens is simply not working the way it should.
If you're trying your lens in similar conditions and you're unclear on whether it's happening or not, then I would guess that it is not. It is an extremely obvious issue. Consider yourself lucky. ...Show more →
Sam, I'm not doubting your skill as a photographer and I'm not questioning your integrity here. You've been very forthcoming with your assessments and have contributed immensly to this thread. But I have to wonder if some of these guys are truly experiencing a back-focuing problem or is it simply user error in some cases. I think it's a fair question to ask. Like I said, I'm giving the benefit of the doubt to the folks that are experiencing this problem, but would still like to see samples posted from those who have claimed to have this issue, but have not provided evidence to support it. I'm interested in hearing what Canon has to say about this, so I'm tracking this subject with keen interest.
Edited by lord_malone on Feb 08, 2007 at 10:15 PM GMT
I didn't shoot any of the test chart at 2.8 BUT my test shots show that the L lens isn't as sharp as the 50 f/1.4 b/w f/2.0 and f/4.0. After that... they are pretty even.
BUT, the f/1.2 in my opinion focuses faster and has overly superb color and contrast. I don't regret getting this at all even though the price tag is totally not justifiable. This should be a 800-1000 lens like the 35 f/1.4 or 24 f/1.4.
Honestly, it seems like this is suffering from shake more than anything. At 1/5th it could just be vibration from mirror slap.
In any case, it doesn't make any sense that the 50/1.2L should be softer than the 50/1.4 @ f/2.8. I cannot think of another consumer vs. L comparison where that's the case. It instantly sets off alarm bells for me, especially considering what I know from my own experience with two copies. Without assessing focus accuracy, there's no way to know whether you're experiencing a "soft lens" or a misfocusing lens.
lord_malone wrote:
Sam, I'm not doubting your skill as a photographer and I'm not questioning your integrity here. You've been very forthcoming with your assessments and have contributed immensly to this thread. But I have to wonder if some of these guys are truly experiencing a back-focuing problem or is it simply user error in some cases. I think it's a fair question to ask. Like I said, I'm giving the benefit of the doubt to the folks that are experiencing this problem, but would still like to see samples posted from those who have claimed to have this issue, but have not provided evidencet to support it. I'm interested in hearing what Canon has to say about this, so I'm tracking this subject with keen interest. ...Show more →
Sorry if that came off as overly defensive. You're right - it is quite easy for user error to creep into this, especially at these distances. I've found that to get really consistent, reliable results I not only have to shoot with flash and on a tripod, but I also shoot tethered (or on a timer) since even slight pressure with your hand on the camera while shooting can throw it out. This is also part of the reason why I shoot so many shots for each test.
But again, with a lens misfocusing as badly as this, the problem is so incredibly obvious that it should be clear even when tested under unideal conditions. Part of the reason I want to make that clear is that it seems like some people with good lenses may be psyching themselves out a bit on this one. No need to create a problem if there isn't one.
I am assuming those "fat free" shots are 100% crops. The 2.8 shot from the f1.2 lens is very poor. Having gotten that far in testing, though, I would next use manual focus to bracket AF in both directions by several very small steps. If you get a sharp image in the bunch, it would prove it's AF error, not an optical problem. If you go far enough, you could even overcome the theorized focus plane shift that might be occurring with stopping down.... If you're in the mood, I for one would love to see the results.
If you go far enough, you could even overcome the theorized focus plane shift that might be occurring with stopping down.... If you're in the mood, I for one would love to see the results.
For what it's worth, I think I've successfully established this is not the issue. I purchase an Ec-B split-prism focusing screen and tested focusing with the lens wide-open, and then focusing with the lens stopped down (by using DoF preview) - the result was the same. Focusing in either case with the split-screen results in a perfectly focused image. If focus shift was an issue, the wide-open shot would be out, while the stopped-down shot would be in focus.
Okay okay... poor testing practice on my part... I apologize. I have been too excited just getting this lens and got lazy. This was shot with the lens as perfectly perpendicular to the target as possible (I only have a ballhead though and this would work better with a pan and tilt). Mirror lock up activated / remote release and ISO bumped to get a bit more speed in. They look pretty close (maybe even a slight edge to the f/1.2). I deleted my original misleading post... again... apologize for providing misleading information.
In testing, this lens is one hard cookie to test. Everything has to be perfectly perpendicular for the results to look sharp. I think in real world shooting, this will be less of a problem.
1/15 f/2.8 (one on left is f/1.2 and one on right is f/2.8)
Part of the reason I want to make that clear is that it seems like some people with good lenses may be psyching themselves out a bit on this one. No need to create a problem if there isn't one.
No worries. I didn't think you were being defensive. Even if you were, I can totally understand as this can be very frustrating. Especially for those who have already had multiple copies. For all we know it may not even be the lens at all. It could be that there's a communication problem between certain bodies and the lens, and a simple firmware update may address this. Only time will tell for sure.
And then there's the question about whether or not there is some sort of "mass-hysteria-buyers-remorse" thing going on as well. Absolutely. People paid a high premium for this lens in spite of naysayers saying that the idea of a $1600 "normal" lens is utterly ridiculous. Now that these problems are surfacing, maybe there's a certain degree of panic? The realization that they could've had a fast 50mm that performed realiably for a fraction of the cost? Maybe convincing themselves that their lens is backfocusing and getting their money back before it's too late? Here's what I wrote in response to posts in another forum...
Well, the 50L had a lot of haters from the very beginning. I think we all saw that coming. Even before it was released, the proposed price point doomed the lens from the start. Many had already dismissed it based soley on the fact that it was priced out of reach for those who may have considered it. You must understand that there are people who are taking great satisfaction in seeing this overpriced lens fail. That is if you consider the BF issue in some copies "failing". When there isn't a back-focusing issue, the 50L is every bit as good as any Canon L prime in the mid-range out there. This lens definitely isn't for everybody. But those who own it and use it will appreciate and value the lens for what it offers. And as long as they're getting the shot, and the tool is doing what it is designed to do, who cares if the general public likes the lens or not? Is this a popularity contest or photography?...Show more →
So how do we weed out those who legitimately have a BF issue from those who aren't sure, but think they are?
I handled it a couple weeks ago and found its size offsets the half-stop wider opening when compared to the smaller 50/1.4 ... unless you plan to use it on a tripod...
I guess what I'm saying is that the smaller, lighter lens can be handled much more steadily at slower shutter speeds in low light situations...sorry but that's how I see it...
lord_malone wrote:
So how do we weed out those who legitimately have a BF issue from those who aren't sure, but think they are?
That's a tough one, unfortunately. As I said before, I think the issue is obvious enough that ultra-rigid testing isn't absolutely necessary. If you can shoot five 3/4 view headshots of someone (one eye closer to the camera) and the eye you focussed on is reasonably in focus for most of the shots, then the lens is probably fine. But the majority of the shots are focused on the wrong eye, you have a problem. Seems pretty basic to me, but as usual the variables involved in that sort of shot apply - make sure your subject is still, make sure you're still and that you don't recompose after focusing, etc.
The important thing is that any sort of test that doesn't give an indication of front/back focus should be avoided. Shooting a brick wall straight on isn't going to show the issue.
lord_malone wrote:
Especially for those who have already had multiple copies. For all we know it may not even be the lens at all. It could be that there's a communication problem between certain bodies and the lens, and a simple firmware update may address this. Only time will tell for sure.
i've talked to people with a 1DsII, 1D2N, an 5D who have had focusing issues with this lens. originally i thought that my 1Ds was the cause of the issue but the three aforementioned bodies are all newer and have had equal results. the three lenses i bought were UU1000 and UU1200 date codes, somewhat (unscientifically) ruling out any early copy issues. the last test i plan to run is to buy one with a newer date code (UV01+) now that another shipment has arrived from japan. the only thing is that PMA is close and i'm itching for a new body more than i am a 50L right now -- so, i might wait a bit longer.
So how do we weed out those who legitimately have a BF issue from those who aren't sure, but think they are?
i believe we have enough capable testers on this forum who have shown multiple time over that the 50L has AF issues or, at least, that a good number of copies have issues on various bodies under relatively controlled conditions.
Aaron, the problem we keep talking about is only noticeable when stopped down. My lens focuses very well at f/1.2. Try the 3/4 view shot I was referring to at f/2.8.
Hmm... I went back and read a bunch of your posts... help me recreate what you did. So I took these shots at f/2.8, handheld and fired off 3 shots consecutevely... is that right? Focus was on "Wipes"... looks a tad to the left but not too bad. Let me know if that is not the methodology. Was at about a 45 degree angle from the box.
All this testing is making me go blind... I'll have to continue this tomorrow
Canon should seriously look into this issue. It could be due to spherical abberation and field curvature problem. Might not be due to manufacturing defect, more like design problem. If it's a zoom lens, it still can be forgiven, but it's a luxury prime L lens...
hoping to get a second batch lens.
