That was the big flaw of that video you linked to, the author didn't seem to understand the real problem that some 70Ds had.
The real AF problem that was experienced by some (primarily early production models sold in Germany) with the 70D was a difference in focus between the center AF point when using the center f/2.8 AF point, and the focus when using the surrounding f/5.6 AF points.
I thought the 70D problem was that (on the cams that have this problem and lenses with max aperture of f/2.8 and lower) with single point center focus the viewfinder focus was "off" when compared with the Live View AF.
NO!!! That is perfectly NORMAL. (see
"This lens is soft" and other myths)
It is if the f/2.8 AF point is giving you different focus than the other PDAF (viewfinder) AF points. That is not normal and is an issue.
Yes, I am familiar with the German video that identified the issue.
Rest assured I do plan to use the DotTune method for MFA.
I am very confused reading your responses. I understand the initial issue you mentioned. The one I have heard about and that many people are taking about is.. With fast lenses and single point auto focus (center), the images taken using the viewfinder are out of focus compared to if the same shot is taken with the LCD. If someone does a controlled test (tripod and shutter release/10 second timer) and they focus on the same spot very carefully..images take with viewfinder should be just as sharp as they are when taken using the LCD. Unless I missed something you posted I don't get how someone could disagree that that's an issue.
Because it is NORMAL as long as it is correctable using micro focus adjustment.
Please read this article to understand why:
"This lens is soft" and other myths
I understand and I just read that article..the 2 concerns I have are. I don't know about this so correct me if I am wrong. If you take 2 pics. The focus from the live view one is spot on and then the one from the view finder is soft or off...how is that normal?
Because they are using two different focus systems. When looking through the viewfinder the camera uses a separate phase detect AF sensor to determine the distance to the subject, and tells the lens to focus at that distance.
When using the LCD the focus is being done by the image sensor itself.
It is perfectly normal for the PDAF system to be slightly off. In the past the only way to correct this was to send the camera into Canon for calibration. But, with a camera that has micro focus adjustment, you can perform the calibration yourself.
By performing the calibration yourself variations from lens to lens can be adjusted for rather than sending every lens and the camera into Canon for calibration.
If you MFA is that not affecting the live view focus..which is already spot on
No MFA only affects the phase detect (viewfinder) auto focus system
The second thing. If there is something from above that I'm wrong about..and you do MFA...and the focus is still different between the view finder and live view then that's an issue.
If you do MFA adjustment properly there should no longer be a difference between the LCD (image sensor) focus, and the viewfinder focus.
That is what most people are referring to. People are doing controlled tests after MFA and getting the same results. Good focus with love view and bad with view finder.
Then they most likely didn't do the MFA properly.
Again, I highly recommend the DotTune method. And keep in mind that MFA should be done in the light you normally use the lens in, and at the distances you normally shoot at.
Thank you for the quick replies and you cleared up the MFA questions about live view vs LCD...but are you saying that every single person that tests this issue is doing something wrong?
No, but, I am saying that people who think that there is something wrong with the camera because you have to use MFA are wrong.
If someone with experience does MFA and still has the issue you still think it's them and there is no chance of it being the camera?
There is always a chance that it is the camera and not the person.
I don't believe that at all.
Sorry, that person didn't understand the actual issue, and as I recall after micro focus adjusting his lenses he eliminated the issue in most of the lenses. Any remaining issues with a lens or two were most likely contributed to the lenses and not the camera.
It's not that hard to take 2 pictures. If you MFA and still have bad focus with the view finder that is 100% not normal.
No, it is not normal. Done properly MFA should eliminate any variation between the LCD (DPAF sensor) AF and the viewfinder (PDAF) AF.
Just another random thought. You explained that the view finder and the LCD each use a different focus system....Ok so how come with everyones testing it's the view finder that has the issue.
Because the sensor AF uses a combination of the dual pixel AF on the image sensor to determine the distance, and then a final contrast detect (looking at the sharpness of the image on the image sensor) for focus.
It's never live view focus causing problems. You said that MFA is for the view finder but how can the live view focus not need it?
See above.
how can it be spot on with all lenses right from the factory but the view finder is not.
See above.
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All statements in my posts represent my interpretation of data, research opinion or viewpoints.
The opinions expressed are not representations of fact, and are subject to change without notice.
All images are used for educational purposes.
