Originally Posted by Jon Ruyle
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You should adjust focus with the widest aperture possible, not the narrowest.
Great catch, Jon - I read that and translated it to 'smallest aperture number possible' (= widest aperture). Ifmatrixman45054 was testing at f/32, the enormous DoF with that narrow aperture would make AF microadjustment practically impossible!
Ah ya good catch guys. I shot the test images at 2.8. As for the other images, some of the others from the same shoot have gotten slightly sharper, but nothing close to that of the rebels IQ (never thought I would say that). I did bump up the camera's "in-camera" sharpening to +7. The default was at +3, but I figured that a little boost couldn't hurt. And by 100%, I mean that the pixels are seen at 100% size.
The test images seemed to be fairly sharp. The problem is that I could never find a adjustment point that was tack sharp. I tried every adjustment from +9 to -9 and everything in between there. At the moment, I have it set to front focus at +5. That seems to be about as good as it will get
The fact that some images are getting sharper than others makes me think that it is an autofocus issue and not necessarily just a calibration issue. Sometimes the AF will hunt for no apparent reason....it can even be in decent lighting and have a clearly defined subject. Granted, both of those shoots were done with all AF points activated. Since then, I also did a shoot where I only activated the center AF point. Those seem to be slightly sharper so far, but I want to take a closer look and see what is going on.
For calibrating again, should I just try it using the center AF point instead of having all points activated? I never thought it would be a problem before because the paper was flat against a wall, but perhaps that could make a difference.
Usually not a good idea, IMO. The camera is going use the AF point on the closest subject (or part of subject, or foreground element). Usually, that's not what you want. I prefer to choose for myself what the actual subject is (generally for portraits, that's the eyes).
Yes, calibration should always be performed with the center AF point. This is especially true for f/2.8 and faster lenses, since the center AF point is a high-precision point with f/2.8 and faster lenses.
On a 5DII at 200mm f/2.8, the DoF should be ~3.5". Instead of a flat sheet of text, have you tried shooting a ruler or focus target at a 45° angle? You can use a chart like this linked one, taped to a door so it's easy to get the angle.
Usually not a good idea, IMO. The camera is going use the AF point on the closest subject (or part of subject, or foreground element). Usually, that's not what you want. I prefer to choose for myself what the actual subject is (generally for portraits, that's the eyes).
Yes, calibration should always be performed with the center AF point. This is especially true for f/2.8 and faster lenses, since the center AF point is a high-precision point with f/2.8 and faster lenses.
On a 5DII at 200mm f/2.8, the DoF should be ~3.5". Instead of a flat sheet of text, have you tried shooting a ruler or focus target at a 45° angle? You can use a chart like [url="http://focustestchart.com/focus21.pdf]this linked one[/url], taped to a door so it's easy to get the angle.
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He beat me to it by a minute. Use center point for focus calibration on a test sheet that is angled at 45 degrees. Also, it's best to calibrate at the focal length you'll be using most.
When I tried my hand at testing my lenses a few weeks back, I used a level and square to square the camera with the wall on which I taped the chart. I wasn't super careful, but I did try. Even so, when I focused on the corner, the center was out of focus and vice versa.
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