7D focusing question

Poe wrote in post #10164155
If you've purchased the lens and camera within a year's time you can send it to canon and they can inspect and calibrate it at no charge to you except shipping.

Yep, you are right and thats what im doing.

apersson850 wrote in post #10166083
Live view focus works by adjusting the lens until the image looks sharp on the image sensor. Since that's the same sensor as registers your pictures, if one is sharp, the other is too.
The normal AF system works with a separate sensor, hence bad alignment of that sensor may cause out of focus images. The same can happen if the lens isn't properly calibrated.

Focusing works the same in P mode as in Av or M or whatever. Only preprogrammed modes, like the green box, are different.
All focusing is done with the aperture wide open, so live view focus differs only if the max opening is smaller than f/5.6. It usually is not, but may be, if you have extenders on slow lenses.

Microadjustment can only change one thing for a lens. A zoom lens calibrated at a repair center is adjusted at eight different points. Don't expect micro adjustment to solve your problem. If it does, it often solves it at a certain focal length, a certain distance to the subject and sometimes even under certain lighting conditions. In other conditions, it may even make things worse.
But if it does solve one problem, it will at least indicate if your lens/camera needs calibration.

I assume Canon should know what to do in these circumstances and what needs to be done to get it corrected, right??????????

tolyD wrote in post #10166973
I dont want to mess with it on my own and make things worse then they are.

You cannot mess anything up. Micro-adjust does NOTHING to the camera or lens, it is just a focus step offset. The camera says "hmmm, the AF sensor shows this to be in focus at this X AF position on the lens, but the user has told me to add or subtract Y amount from the focus position I tell the lens to go to, so I will honor that. Lens, go to position X plus/minus Y from the user, please...."

If you don't like the results, just set it back to 0.

UPDATE: So, I got my camera back from Canon. And what d you know, of course there was something wrong with the focusing as i suspected. So the lens needed some micro adjustment and it looks like they had to set it to -2. Now it seems a bit better but i still have to do some more testing to conform that it is good now.

Sucks that Canon doesn't adjusts these issues before they sell them. Cause of that you have to find it out on your own going threw all this trouble.

?

So there was something wrong with the camera or not? If so, what did they adjust?

And if it was the lens that needed -2 adjustment, that is very minor. You could've done that yourself easily. It's the reason why the camera allows you to go +/-20.

It is unrealistic for Canon to have 1 person sitting there at the assembly line, testing every single camera/lens made. If that was the case, every camera body + lens would be backordered, or they'll be even more expensive. They're built to within specific "tolerances". I'm just happy that they finally started adding MFA feature to the newer bodies so that we can make the minor tweaks ourselves, instead of settling for slightly soft photos and/or having to need to send it back in and be without a camera for days/weeks.

jwcdds wrote in post #10216299
?

So there was something wrong with the camera or not? If so, what did they adjust?

And if it was the lens that needed -2 adjustment, that is very minor. You could've done that yourself easily. It's the reason why the camera allows you to go +/-20.

It is unrealistic for Canon to have 1 person sitting there at the assembly line, testing every single camera/lens made. If that was the case, every camera body + lens would be backordered, or they'll be even more expensive. They're built to within specific "tolerances". I'm just happy that they finally started adding MFA feature to the newer bodies so that we can make the minor tweaks ourselves, instead of settling for slightly soft photos and/or having to need to send it back in and be without a camera for days/weeks.

lens needed some micro adjustments. there is a reason i have paid so much money for this camera. And YES i do expect it to work the way it should be even if its off by -1.

On the other hand, they specifically give us the ability, very easily, to make that adjustment. They explain how to do it in the owners manual. It's a quick easy process that allows you to get each lens just the way you want it.

I'd rather spend a couple minutes making the adjustment that spending the money to send it to canon to make a very simple adjustment.

To me that's sort of like bringing a car to the dealer to adjust the driver's seat. (cause we need another analogy right???)

tolyD wrote in post #10216391
lens needed some micro adjustments. there is a reason i have paid so much money for this camera. And YES i do expect it to work the way it should be even if its off by -1.

So it sounds like they did NOTHING physical to the body or lens, you send them the body and lens for them to go to a menu and set a -2 in the MFA CF screen?

You would have spent much less time doing a few test shots, setting a microadjustment value, etc than to send it in. The tools are included with your camera to allow you to make the most of your equipment, it just takes patience and a bit of reading/learning.

tolyD wrote in post #10216391
lens needed some micro adjustments. there is a reason i have paid so much money for this camera. And YES i do expect it to work the way it should be even if its off by -1.

There is a reason that they give you the ability to MA in the camera. If you want the best out of your equipment, you might have to put out some effort. It's just the way it goes. Won't be any different with any other brand.

timberlakephoto wrote in post #10216439
On the other hand, they specifically give us the ability, very easily, to make that adjustment. They explain how to do it in the owners manual. It's a quick easy process that allows you to get each lens just the way you want it.

I'd rather spend a couple minutes making the adjustment that spending the money to send it to canon to make a very simple adjustment.

To me that's sort of like bringing a car to the dealer to adjust the driver's seat. (cause we need another analogy right???)

i did try to adjust it myself reading the manual and it gotten worst so i sent it in. Who knows maybe there was something wrong with the body as well. they didnt tell me anything. all i got back is the camera with some paper that doesnt really says much what they did to it. I discovered the micro adjustments myself when i went to the cameras setting.

This is exactly why Canon needs to couple their Live View functionality to the micro-adjustment feature. I and others stated this over a year ago, and it still holds true. There is no reason now with the Live View contrast AF that the camera could not do a series of steps that would self-micro-adjust.

1) User sets up on tripod at a high contrast object parallel to lens
2) Camera AFs using center point
3) Camera switches to Liveview
4) Camera contrast AFs
5) Camera takes delta of focus settings between 2 and 4, and sets it for the lens
6) Repeat up to 3 times or until there is no difference between 2 and 4

Now the person has a great starting point for any tweaking of MFA.

TeamSpeed wrote in post #10216844
This is exactly why Canon needs to couple their Live View functionality to the micro-adjustment feature. I and others stated this over a year ago, and it still holds true. There is no reason now with the Live View contrast AF that the camera could not do a series of steps that would self-micro-adjust.

1) User sets up on tripod at a high contrast object parallel to lens
2) Camera AFs using center point
3) Camera switches to Liveview
4) Camera contrast AFs
5) Camera takes delta of focus settings between 2 and 4, and sets it for the lens
6) Repeat up to 3 times or until there is no difference between 2 and 4

Now the person has a great starting point for any tweaking of MFA.

this is exactly what people need and complains will stop about this issue. This focusing problem makes 7D look really bad. You should work for Canon and show them what's up.

Live View focus and regular AF each have their advantages and disadvantages. Live View uses edge contrast detection -- its advantage is that it is very accurate even in low light, but its disadvantage is that it is very very slow as Ken stated in his first post. Regular AF uses phase detection -- its advantage is that it is extremely fast, but its disadvantages are that it is not as accurate as the slow contrast detection and its accuracy is more affected by the amount of light on the subject.

In addition to the differences between contrast and phase detection of edges for focusing, sharpness can also be affected by a combination of lens and camera alignment. Despite all of the high drama and hyperventilation on camera forums, the usefulness of micro adjustability is primarily the result of ultra high resolution sensors like the one on the 7D that are actually able to detect minute lens focus error whereas cameras with 10 MP sensors simply do not have the resolution to show that there is a slight focus error in the lens. Also, with these ultra high resolution sensors, very small alignment position variations of the AF sensor can be detected. I think that it is a pretty clear indication of most of the focus error being in the lens when micro adjustment is performed for each of your lenses and they all have different amounts of compensation to produce optimum results. Some of my lenses require a bit of positive compensation, some require negative compensation, and some do not require any compensation. If they all required about the same amount of adjustment then it might be assumed that most of the alignment offset is in the AF sensor. Since there is no such thing as perfect parts, the ability to tune a system for optimum performance is a really great feature.

Bill Boehme wrote in post #10217700
Live View focus and regular AF each have their advantages and disadvantages. Live View uses edge contrast detection -- its advantage is that it is very accurate even in low light, but its disadvantage is that it is very very slow as Ken stated in his first post. Regular AF uses phase detection -- its advantage is that it is extremely fast, but its disadvantages are that it is not as accurate as the slow contrast detection and its accuracy is more affected by the amount of light on the subject.

In addition to the differences between contrast and phase detection of edges for focusing, sharpness can also be affected by a combination of lens and camera alignment. Despite all of the high drama and hyperventilation on camera forums, the usefulness of micro adjustability is primarily the result of ultra high resolution sensors like the one on the 7D that are actually able to detect minute lens focus error whereas cameras with 10 MP sensors simply do not have the resolution to show that there is a slight focus error in the lens. Also, with these ultra high resolution sensors, very small alignment position variations of the AF sensor can be detected. I think that it is a pretty clear indication of most of the focus error being in the lens when micro adjustment is performed for each of your lenses and they all have different amounts of compensation to produce optimum results. Some of my lenses require a bit of positive compensation, some require negative compensation, and some do not require any compensation. If they all required about the same amount of adjustment then it might be assumed that most of the alignment offset is in the AF sensor. Since there is no such thing as perfect parts, the ability to tune a system for optimum performance is a really great feature.

thanks it was very well explained