85mm 1.8 just returned from Canon WTF!

Yeah tell me about it wouldn't be so bad if I hadn't just got it BACK from Canon for the same exact thing.

Burnaby wrote in post #8118053
Is it me or what? I don't think this image is properly focused on the Center Line. The rear 2mm distance is more focused than the CL, which would explain why there is the appearance of back-focusing. I blew up the image to make sure, and that CL is off... The OP needs to re-do this calibration check/test. The text is certainly NOT perfectly in focus.

Well, that's kind of the point - isn't it? He focused on that line but the camera focused beyond it - hence the issue!

You are aware that the actual area covered by the AF sensor is quite a bit bigger than the "square" in the viewfinder? So although the red square was over the first battery, I'm pretty sure the sensor extends out to the second battery and the AF system just happened to find a spot of high contrast on the second battery.

I haven't followed the rest of your testing close enough to comment on your other results. Good luck in getting it all sorted out, my 85 is one of my favorite lenses!

BigAlz1 wrote in post #8117112
Yeah I would never want anything as small as a battery to be in focus anyway. Never an eyes ball or a watch, heck who needs 1.8? I'll stop it down to f8.0 and make pretend I got 1.8 ability.

JK, just taking a poke at the Idiocracy displayed in some of these posts ima calling Canon tomorrow. Thanks everyone this was interesting at best.

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I had a Canon prime with exactly the same problem; I sent it to Canon twice and they couldn't get it right.

Send it to Canon with the body.

BigAlz1 wrote in post #8117112
Yeah I would never want anything as small as a battery to be in focus anyway. Never an eyes ball or a watch, heck who needs 1.8? I'll stop it down to f8.0 and make pretend I got 1.8 ability.

JK, just taking a poke at the Idiocracy displayed in some of these posts ima calling Canon tomorrow. Thanks everyone this was interesting at best.

no, there are pretty much only four opinions that people are suggesting to you:

1. it has a problem, send it in for a recalibration.
2. it has a problem, but your supposedly controlled tests are inconsistent and you're exaggerating the issue whether it's intentional or not.
3. it has a problem, but it's not a big deal. just go out and enjoy the lens.
4. it has a problem, but since you're stressing so much over it, you're probably never going to be happy with it. just return it and save yourself the headache.

they're all pretty reasonable. i think you're trying to poke fun at suggestion 3, which i find strange. they're just saying as long as you get at least 4mm or so of DOF, you'll be fine. with your 40D, that's not very hard to achieve. if you deal with MFD all the time and NEED that 2mm of accuracy, send it in. it's not that big a deal and you sound like a drama queen when you try to manipulate reasonable solutions into outlandish statements like your f/8 one.

ps: by idiocracy, did you mean idiocy?

The MFD for the 85mm f/1.8 is 2.8ft (about 33inches). At 35 inches, was that from the front of the lens? Or, from the camera body? Either way, its still pushing it for a descent test. I would try this shot at about 5ft away and see if its the same.

BigAlz1 wrote in post #8111196
Same image lol,
Here is a "real" world shot to show how I can't take sharp pictures like I need too.
This is a tripod mounted shot. The knee I focused on is the furthest point toward me. The other knee, crouch and hand that are in focus are 1 and 1/2 inches away from my focus point! The subject is about 35 inches away from the camera.

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5Dmaniac wrote in post #8118111
Well, that's kind of the point - isn't it? He focused on that line but the camera focused beyond it - hence the issue!

Thanks for pointing that out. I'm looking at this lens, thus the interest...

BigAlz1 wrote in post #8117023
User error WOW...... This thread has took on a whole new life of it's own. I just love how you ask for advise and get called stupid....
I am well aware of what MFD is and I was outside that range, you don't get focus confirmation, and can't take the shot in Auto Focus if your not!
Ok back to the point, yes it does back focus that bad, thanks for the real input from the people that have been there and done that. Thanks all except the ones thumping my forehead collecting post counts.
.....

Whether the lens backfocuses or not your original examples points that you have a lot to learn. The photos you posted are so inconsistent that can confuse anyone. You smartly substituted the images since then making the comments to that image looking irrelevant ( how ethical is that ? ). Anyway I am sorry that I spent my time trying to help you. Good luck with your Canon service request.

How did you perform that battery test? From the position of the batteries and the angle of the camera it doesn't look like a tripod shot. It HAS to be a tripod shot. Nobody is capable of handholding completely still... a very slight movement will throw your focus off especially if you are close to MFD and shooting wide open. Also, your batteries are clustered so close together that it's almost impossible for the camera to know which battery to focus on.

Put your camera on a tripod, put ONE battery out for your camera to focus on. Make sure there is NOTHING with contrast in the background. Let it focus and take the shot. Then add a couple more batteries (NOT touching the first one) some in front some behind, and then take another shot WITHOUT refocusing. Then analyze the shots.

Though this isn't a great test either. But the 45 degree chart test is about the worst thing around. That stupid chart has put me through much agony over nothing.

This thing is getting weirder by the minute...

picturecrazy wrote in post #8120302
How did you perform that battery test? From the position of the batteries and the angle of the camera it doesn't look like a tripod shot. It HAS to be a tripod shot. Nobody is capable of handholding completely still... a very slight movement will throw your focus off especially if you are close to MFD and shooting wide open. Also, your batteries are clustered so close together that it's almost impossible for the camera to know which battery to focus on.

Put your camera on a tripod, put ONE battery out for your camera to focus on. Make sure there is NOTHING with contrast in the background. Let it focus and take the shot. Then add a couple more batteries (NOT touching the first one) some in front some behind, and then take another shot WITHOUT refocusing. Then analyze the shots.

Though this isn't a great test either. But the 45 degree chart test is about the worst thing around. That stupid chart has put me through much agony over nothing.

I noticed this as well. The upwards, slanted angle suggests handholding. If you really feel like being anal about it, use MLU and/ or timer. When you're trying to analyze a DoF of a few millimeters, you can't take shortcuts.