24-105 front focusing, or ?

[shutterdown]

I sent my lens to Canon, for adjustment. They said that the AF focusing mechanism was not functioning properly (don't remember this being a problem, and I've never mishandled this lens).

They sent it back. I did a family photo shot, and the back row of people was out of focus.

The shot was taken in manual mode, using a couple of speedlights. f/8, 45 mm, 1/200 sec. I used a 5DII. Distance from the front row was 11 feet. I used the center focus point, and focused on the person's face, sitting in the center of the front row. (disconnected the shutter button and used the back AF button for this purpose). Everyone was in a straight line in both rows.

The second row of people were about 1ft to 18 inches (max) further back from the front row.

The image showed the back row out of focus. I didn't notice this on the LCD, of course.

Based on the depth of field, both rows should have been in sharp focus.

A year earlier, I did a similar shot, and everyone was in very sharp focus (13 ft from the lens).

Also, I redid a test with two people, using my 24-70, under the same conditions, and both people were in sharp focus.

Canon supposedly adjusted the lens, but it's worse than when I sent it in.

Is this a calibration error on their part? Or, do I need to do an adjustment myself? Or, should I just send it back to them for correction?

[andnowimbroke]

Your right. You shouldn't have had any problems with things out of focus. Was the camera and the lens sent in, or just the lens. The only thing I could have thought of is it messed up the settings used for AFMA, and it would need to be redone. But even at that, F8 should have had most everything in focus.

[neuroanatomist]

Did you send the body in, too? When they calibrate, they do it using an 'ideal' body - your lens and body may have both been off before, two wrongs making a right.

Have you done an AFMA?

[shutterdown]

I sent just the lens.

Do you think that the AFMA will solve the problem?

Before I sent it in, I didn't have a problem with the focus. As I mentioned, I did a similar shot a year before, and it was spot on.

[shutterdown]

What puzzles me is why I would need to send the body in, too, since when I bought this lens, it worked perfectly on my 5DII. I had tried an AFMA on it, previously, but it didn't give me satisfactory results, being a zoom lens. I wasn't sure which end I should do the adjustment, so I left it as is. But, that wasn't a negative, since the lens was quite sharp without any adjustment.

So, now, I've got a lens that isn't what it was when I bought it, and all I would like Canon to do, is bring it back up to the specs that existed when I bought it, originally.

[HDNitehawk]

It wouldn't hurt. The Camera and Lens could be the culprit in a problem. Good idea to do it.

But just because it misses one set of shots doesn't necessarily mean it is off. AF systems are only so accurate. To have been completely OOF it would have to have missed by over 2' in front with the settings you gave.

If this has been happening often I would do the AFMA. Actually I do the AFMA on all my lenses regardless just so I know how they perform.

[HDNitehawk]

What puzzles me is why I would need to send the body in, too, since when I bought this lens, it worked perfectly on my 5DII. I had tried an AFMA on it, previously, but it didn't give me satisfactory results, being a zoom lens. I wasn't sure which end I should do the adjustment, so I left it as is. But, that wasn't a negative, since the lens was quite sharp without any adjustment.

So, now, I've got a lens that isn't what it was when I bought it, and all I would like Canon to do, is bring it back up to the specs that existed when I bought it, originally.

The components inside the camera are very sensitive. If there off a bit they will send the wrong information to the lens. You could have bumped it or shaken it, or just general wear and tear changed things. If you compare the lens all the way through all of the settings then you can decide what is appropriate. There is nothing wrong with switching settings in the field if a subject is closer or further. Or you could do an average of the two ends. I prefer to set to the long end since the DOF is narrower there.

It my understanding that there is variance in the mfg process, notice the latest release of the 24-70 II. So it is best to send camera and body in that way Canon can make sure it matches manufactures specs in performance.

[shutterdown]

The components inside the camera are very sensitive. If there off a bit they will send the wrong information to the lens. You could have bumped it or shaken it, or just general wear and tear changed things. If you compare the lens all the way through all of the settings then you can decide what is appropriate. There is nothing wrong with switching settings in the field if a subject is closer or further. Or you could do an average of the two ends. I prefer to set to the long end since the DOF is narrower there.

It my understanding that there is variance in the mfg process, notice the latest release of the 24-70 II. So it is best to send camera and body in that way Canon can make sure it matches manufactures specs in performance.

Rick, when you say "bumped it" do you mean the camera? If so, I guess it's possible that I could have bumped it.

This OOF issue is severe, though. I should have gotten at least 7 feet of focus BEHIND the subject, and I didn't. I did get sharp focus with my 24-70 (version I).

Something changed with the lens, and I have a hard time believing it's my camera/lens combo with the 24-105. When Canon sells a lens, they might do it on an ideal body, true. But, they just sell the lens, and people put it on their cameras, and none of those cameras have been calibrated with the lens they bought. That means, something funky happened when they "fixed" my lens.

I do AFMA on my primes, but I've not had good luck with the zooms.

[HDNitehawk]

If they took the thing apart when you sent it in, and replaced or fixed something really you do not have the same lens. It may need a substantial adjustment to work now. You could always send it back to Canon and I am sure they would retest it.

The thing about on the 24mm end I have always found it tough on wide lenses to get a good accurate adjustment. But at 45mm you shouldn't have a problem. Zooms are a little tougher than the primes, there not as accurate and the vary over the range but you can get an idea.

[shutterdown]

That's what I'm planning on doing, first of all.

By the way, I see that you bought the v2 of the 24-70. With Bryan finding variations in it, how is yours working?