backfocussing on 70-200 f4

[loebas]

After borrowing this lens this weekend, i got very impressed by the photos i/the lens took.
Think of buying one, but the backfocus problems mentioned on this and other forums make me doubt.
Following questions:
How is d300 working with this lens ? (D10 seems notorious)
Can someone post normal photos were you can see backfocussing (please no lines with number photos.

Looking forward to hear from you

[lmelendez]

After borrowing this lens this weekend, i got very impressed by the photos i/the lens took.
Think of buying one, but the backfocus problems mentioned on this and other forums make me doubt.
Following questions:
How is d300 working with this lens ? (D10 seems notorious)
Can someone post normal photos were you can see backfocussing (please no lines with number photos.

Looking forward to hear from you

Hi loebas,
- The backfocus problem is a camera issue and as far as I know, it can be fixed (recalibrated by Canon).
- 70 - 200 f4 L is a great lense. I have the 2.8 version and it works great with my 300D.
- What do you mean by "please no lines with number photos"??

Leo.

[loebas]

Hi loebas,
- The backfocus problem is a camera issue and as far as I know, it can be fixed (recalibrated by Canon).
- 70 - 200 f4 L is a great lense. I have the 2.8 version and it works great with my 300D.
- What do you mean by "please no lines with number photos"??

Leo.
Lines and numbers, I mean you often see white paper with small black lines on it and below these small lines you see numbers.
They use this chart to see if you camera/lens has backfocus.
I think this are very created circumstances which will prove yes or no.
But I wonder if you see the yes proval back in real photos.
Hope its clear for you

[lmelendez]

Lines and numbers, I mean you often see white paper with small black lines on it and below these small lines you see numbers.
They use this chart to see if you camera/lens has backfocus.
I think this are very created circumstances which will prove yes or no.
But I wonder if you see the yes proval back in real photos.
Hope its clear for you

Well, when I first got my 300D, I tried taking some pictures at f1.8 with the 50mm lense and noticed that the sharpest area of the picture was always behind to the point where I think it was focusing.

When I got the 70-200 f2.8, did similar tests and the 300D was still giving me pictures where the sharpest area of the picture was behind the point where I think it was focusing.

It doesn't mean it has the problem, but I suspect it might. I want to repeat the test with the "lines and numbers" as you call it and then decide if I want to send the camera to Canon so it can be calibrated.

Now, please note that I don't know a lot of stuff about this. Let's better wait for the experts to give their opinion :)

Leo.

[Jon]

Lines and numbers, I mean you often see white paper with small black lines on it and below these small lines you see numbers.
They use this chart to see if you camera/lens has backfocus.
I think this are very created circumstances which will prove yes or no.
But I wonder if you see the yes proval back in real photos.
Hope its clear for you

You'll see these because, as you say, they prove that your camera/lens combo has this problem. Live photos "in the field" are less satisfactory because you can't be sure if the problem's with the camera or with how it was used (was the camera actually focussing on what you thought it was? will we recognize what you were focussing on?). So I might have some photos displaying back-focus, but you wouldn't recognize it as such because you were looking at the subject differently.

[Citizensmith]

And as ususal the my X has a problem with X comes from a small but vocal minority. People don't complain when things work perfectly. So chances are you'll get a lens with absolutely no issues, and if there are any they can be fixed.

I know my 70-200 f/4L on my 300D is just fine.

[loebas]

You'll see these because, as you say, they prove that your camera/lens combo has this problem. Live photos "in the field" are less satisfactory because you can't be sure if the problem's with the camera or with how it was used (was the camera actually focussing on what you thought it was? will we recognize what you were focussing on?). So I might have some photos displaying back-focus, but you wouldn't recognize it as such because you were looking at the subject differently.

Thank for this explanation.
Where I wonder about is that you never read about backfocus problems with the kit lens 18-55.
Means L lens that you get backfocus or ...?

[Jon]

Thank for this explanation.
Where I wonder about is that you never read about backfocus problems with the kit lens 18-55.
Means L lens that you get backfocus or ...?

. . . people with the kit lens may not be looking as hard at their images. Not a slam - but if you're pouring $700 into a lens, you're going to look harder at what you get than if you get one thrown in for $90-100 more than the camera. Sort of like a pre-delivery inspection of a Cadillac vs. a Chevy. They may be the same car under the skin, but the Caddy driver's going to be fussier.

[loebas]

. . . people with the kit lens may not be looking as hard at their images. Not a slam - but if you're pouring $700 into a lens, you're going to look harder at what you get than if you get one thrown in for $90-100 more than the camera. Sort of like a pre-delivery inspection of a Cadillac vs. a Chevy. They may be the same car under the skin, but the Caddy driver's going to be fussier.

Maybe youre right but, although the 18-55 is a "lower" quality lens, i took great photos with them, if you have any kind of backfocus, you must also notice this with this lens.
Or am I wrong

[Jon]

What I was trying to say was that until people moved up to the range of L glass, they probably weren't looking at their pictures as closely. Of course, the 18-55, by virtue of its shorter focal length and smaller maximum apertures will have greater depth of field at any given distance, so a backfocus or frontfocus problem won't be as obvious even if you do have a problem.